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Miscellaneous Small Engine and Garden Tractor Pulling Tips & Tricks
(Information that don't fit in any other category.)

Serving the Small Engine and Garden Tractor Pulling Community Since 1996. Where Science and Common Sense Come Together for Safety and Better Engine/Tractor Performance
A-1 Miller's Performance Enterprises - Parts & Services Online Catalog

FOR SALE - Professionally Built Self-Propelled Pulling Sled for ATVs/UTVs, Garden Tractors & 1,500 lb. Small Wheel Mini Rods w/26-12.00x12 tires. Go here for information, YouTube videos and more pictures of this sled: HRGTPA.com. $10,000.00 firm. If interested, contact Brian Miller at 573-881-7229 (cell; text or voice mail) or email: pullingtractor@aol.com. We're planning to move up to a more popular and high-in-demand pulling entertainment.

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The Importance and Safety of Having Wheelie Bars on a Pulling Tractor (Updated 11/4/05) [Top of Page]

If a pulling tractor is going to run a 13" drawbar height with 26x12.00-12 tires, it must have wheelie bars properly installed, even if a club or pull site doesn't require them. Because a pulling tractor can flip back so quickly, without warning. The rear tires are rotating in one direction, which forces the tractor to want to rotate in the opposite direction. ("For every action, there's an equal and opposite reaction." - Newton's third law of motion.) So for safety sake, it's best to have wheelie bars installed for pulling regardless of the height of the drawbar or tire size. Wheelie bars are sometimes referred to as a "no-tip device." Wheelie bars are one of the easiest things to install on a pulling tractor. Only an idiot or someone with a death wish would pull a tractor without wheelie bars!

The pads or wheels for the ground contact needs to be of adequate size too, to prevent from sinking into soft earth. The pads need to be a minimum of 3" square x 1/8" thickness and wheels need to be a minimum of 4" diameter x 1" wide. Most pullers prefer to use wheels on the wheelie bars. They allow the tractor to gain an inch or two because they "roll." The pads on the other hand scrape on the ground and doesn't allow the tractor to get much further. And it's a good idea for stock tractors to run a 10" drawbar height anyway to prevent breaking a stock rear end.

For best stability of the tractor when the front end raises upward, most club's rules state that the bottom of the wheelie bar wheels or skid plates are supposed to a maximum of 5" from the ground. And the rear of the wheelie bar wheels or skid plates are supposed to be a minimum of 5" from the tread of the rear tires. Scroll down to see drawing for a better explanation. Check out this YouTube link: When it's important to have wheelie bars on a pulling tractor!

For safety reasons, make your wheelie bar bracket material rigid and not spring-loaded. They must be made of heavy wall (minimum 1/8" thickness) tubing and reinforced for strength. Also, bolt on the wheelie bar brackets and don't weld them to the frame. So they can be adjusted if necessary. See the pictures below Ê for what typical wheelie bar brackets look like:


NOTE: The wheelie bar brackets shown above were fabricated by the individual who owns each tractor.

IMPORTANT! And be aware when using flat aluminum wheelie bar braces. If the tractor were to stop suddenly on the track, and the sled bumps the rear of the tractor, the braces may bend to the side from the impact. And straightening them so they'll look original again is almost impossible. Therefore, we think it's better to use 1-1/2" x 1-1/2" x 1/8" wall square tubing as wheelie bars. When the sled bumps wheelie bars made of heavy wall square tubing, the whole rear of the tractor will move sideways slightly, and the wheelie bars won't suffer any damage.

Advertisement:
If you would like to purchase any of the parts or services listed in this website, please contact A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's shop to personally drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

Heavy Duty Plastic Wheelie Bar Wheels with smooth tread surface. Weighs less than 10 ounces each. Lighter in weight than all-aluminum wheels or steel wheels w/rubber tread, but just as strong. Dimensions: 5" tall x 1-3/8" wide x 1/2" center hole w/metal bushing. Our part # 84-1061.

  • $8.00 per pair, plus shipping & handling.

How to set the wheelie bars for proper height so the front end won't be too high or too low when the front tires comes off the ground:

  1. Install the front and rear tires that you're going to use at the pulls on the tractor.
  2. Raise the front of the tractor (using a hoist or ramps) until the bottom of the front tires are about 16" off the ground.
  3. Set the wheelie bars w/wheels or skid pads on the ground.
  4. Mark and drill holes in the frame or transaxle to fasten the wheelie bar brackets.
  5. Use 3/8" diameter grade 8 bolts to fasten the wheelie bars!


Rear Safety BumperIMPORTANT! About Rear Safety Bumpers -

When a high speed garden tractor gets going down the track really good, and all of a sudden it's engine stalls and the tractor comes to a complete stop, what's going to happen? Chances are the sled will bump the rear of the tractor. Most sled operators can't put the brakes on in time or react fast enough because this can happen so quickly. Therefore, it's a good idea to install a couple of heavy-duty rear "bumpers" mounted on or incorporated into the wheelie bar brackets located a minimum of 6" above the wheels or pads. (Most club's rules and regulations will or should specify the location.) These bumpers will keep the sled from possibly getting up on top of the rear tires, causing damage to the tractor and/or injury to the driver. And the bumpers will prevent the pull chain from getting "wrapped" around one of the rear tires should the tractor go sideways to the extreme.


IMPORTANT! Safety of Pulling -

All tractor pullers, despite their age, needs to be educated on safety requirements and proper operation of a pulling tractor. Because many of them, when the tractor they're sitting on is hooked to the sled, will rev it up and give it all it's got, and they'll do whatever it takes to win. Some even get injured by doing so. They think it's a "no-holds-barred" contest.

We've seen a few garden tractor pullers would launch the sled (not our sled) at the sting line, when all of a sudden their tractor would flip backwards and sometimes the puller will hit the back of their head dirt shield that's on the front of the skid pan because no wheelie bars were installed on their tractor. They weren't seriously injured. But it's scary to actually witness something like that in person! It's not a funny thing to happen and certainly not part of the show!

We were at a pull several years ago [with a now defunct pulling club that was based in central Missouri], when an inexperienced adult person on a stock garden tractor was pulling the sled [not our sled] down the track when all of a sudden the front of the tractor reared up and stood on end, then it caught on fire. What caused this is the tractor had 26-12.00x12 lug tires, about a 16" drawbar height and no wheelie bars. It also had a loose-fitting gas cap with a full tank of gas, which was positioned on top of the engine, and the battery, which was positioned between the gas tank and steering column, wasn't fastened down. When the tractor stood on end, the gas cap fell off, gas spilled out onto the battery and on the driver. Then the battery tipped back, shorting out the posts against the metal steering column support, which ignited the fuel. It was a horrible sight! The flames were immediately extinguished and the puller had to be air-lifted to the nearest hospital with a burn unit. He recovered from his injuries, but he now has scars on his chest and groin area to remind him of that horrible day at a tractor pull when he was just trying to have some fun with his friends. Not to mention the mental scars it left, too. An official of this particular pull should have inspected that tractor and all other tractors for safety, and not allow the puller to participate if the tractor wasn't safe or legal, or if an adjustment wasn't made.

Tell your friends and family about this story. And tell them to definitely install sturdy wheelie bars with skid plates or wheels, whether if they feel they need them or not, or if the rules require them or not. Remember - friends don't let friends pull without wheelie bars (and other safety equipment). And NEVER allow a young person to participate in a pulling event without wheelie bars (and of course, other safety equipment) properly installed and maintained.

IMPORTANT! We've been to a lot of garden tractor pulls over the years and noticed that some tractors leak fuel in places where a fuel leak shouldn't be. Therefore, we think that safety inspections needs to include checking the fuel lines for dry-rotting, cracks, fuel leaks, loose fittings, etc. (The tractors should have sturdy wheelie bars, too.) The inspectors needs to grab hold of the fuel line(s) with their hand and wiggle it around and slightly jerk on it to check for durability. This is important. Especially in a kid's class. Don't wait until an issue becomes a problem, and then turn into a catastrophe. If pullers would build their tractors right to begin with and maintain them properly, there wouldn't be any injuries, fires, or fear of a fire.


Useful Formulas, Conversion Charts, etc. [Top of Page]

It's best to use a handy calculator here, have pencil and paper available, or have JavaScript enabled in your web browser.


To calculate the cubic inch displacement (CID) of an engine:
Bore x Bore x .7854 x Stroke x Number of Cylinders = Cubic Inch Displacement.
Example: (for a 4.3L Chevrolet V6 engine) 4.000 (bore size) x 4.000 (bore size again) x .7854 x 3.48 (stroke) x 6 (number of cylinders) = 262.37 CID.

Calculate Engine Cubic Inch Displacement

Enter Cylinder Bore:
Enter Crankshaft Stroke:
Enter Number of Cylinders:
= Engine Cubic Inches:


To convert CID into Cubic Centimeters (CC): (1 Cubic inch = 16.3870641 Cubic centimeters)
Multiply the CID by 16.39 = Cubic Centimeters.
Example: 262.37 (CID) x 16.39 = 4300 CC.
To convert CC back into CID: 1 Cubic centimeter = 0.0610237 Cubic inches.

1 Cubic Inch = 16.39 Cubic Centimeter

Enter Cubic Inches: = CCs:


To calculate engine cubic centimeters (CC) for the approximate horsepower, first convert the CC's into the cubic inch displacement (CID) by dividing the CC's by 16.4, which will show the approximate CID. Then for a flathead engine, divide the CID by 2.45, which will show the approximate HP of the engine @ 3,600 RPM. And for an OHV engine, divide the CID by 1.45, which will show the approximate HP of the engine @ 3,600 RPM.



To convert CC's into Liters: (1 Cubic centimeter = 0.001 Liter)
Divide the Cubic Centimeters by 1000 = Engine Liter Size.
Example: 4300 ÷ 1000 = 4.3L.


231 cubic inches = 1 US gallon

Enter Cubic Inches: = Gallon:


Finding the Correct Piston Compression Height -
(Piston Compression Height is the distance from the wrist pin centerline to the top of the piston.)

Enter Deck Height: (From main bearing centerline to top of block. The deck height on the OEM Kohler 10hp through 16hp engine blocks is 8.625")
Enter Crankshaft Stroke: (OEM Kohler is 10hp = 2.875", 12hp, 14hp & 16hp = 3.25")
Enter Rod Length: (from wrist pin hole centerline to rod bearing hole centerline. OEM Kohler is 10hp is 5.558. 12hp, 14hp & 16hp = 5.3")
Enter Piston Compression Height: (OEM Kohler is 10hp is 1.63", 12hp, 14hp & 16hp is 1.7")
= Deck Clearance: (0 meaning flush w/cylinder)


Rod Length divided by Stroke = Rod Stroke/Ratio

Enter Rod Length:
Enter Stroke:
= Rod Stroke Ratio:


1cc = .061 cubic inches

Enter CCs: = Cubic Inches:


How to Calculate the Compression Ratio of a Flathead or OHV Engine -

  1. Acquire a flat piece of Plexiglas slightly larger than the cylinder head, and drill a small hole in it where the combustion chamber of the head is.
  2. Acquire a large test tube with cubic centimeter increments.
  3. Fill the test tube with brake fluid.
  4. Make a note of how much brake fluid is in the test tube.
  5. Seal the Plexiglas over the cylinder head with the head gasket that's going to be used on the engine. (Use silicone sealer)
  6. Fill the combustion chamber with the brake fluid through the drilled hole.
  7. Make a note of how many cubic centimeters of brake fluid it took to fill the combustion chamber.
  8. Now calculate the cubic inches of the cylinder in the engine. Convert that figure into cubic centimeters.
  9. Finally, divide the cubic centimeters of the cylinder by the cubic centimeters in the combustion chamber. This should give the exact compression ratio.


1 cubic foot = 7.48 US gallons

Enter Cubic feet: = Gallons:


- Identification of and Torque Specifications for the Most Commonly Used Grades of Bolts -
NOTE: Use Standard Torque Settings When Specific Values Are Not Specified. (C) = Coarse thread, (F) = Fine thread
Hardness è No lines = Grade 3

No lines = Grade 3 bolt

3 lines = Grade 5

3 lines = Grade 5 bolt

6 lines = Grade 8

6 lines = Grade 8 bolt

Stainless Steel /
Special Alloy

Stainless Steel / Special Alloy bolts
Bolt/Thread
Size

â
Material: Low Carbon Steel. Tensile Strength: 85,000 p.s.i. (Low Strength) Material: Medium Carbon Steel, Tempered. Tensile Strength: 120,000 p.s.i. (Medium Strength) Material: Medium Carbon Alloy Steel, Quenched and Tempered. Tensile Strength: 150,000 p.s.i. (High Strength) 18-8 [304] Stainless Steel
 1/4-20 (C)
 1/4-28 (F)
5/16-18 (C)
5/16-24 (F)
 3/8-16 (C)
 3/8-24 (F)
7/16-14 (C)
7/16-20 (F)
 1/2-13 (C)
 1/2-20 (F)
9/16-12 (C)
9/16-18 (F)
 5/8-11 (C)
 5/8-18 (F)
 3/4-10 (C)
 3/4-16 (F)
 70 in. lb./ 6 ft. lb.
 85 in. lb./ 7 ft. lb.
150 in. lb./13 ft. lb.
165 in. lb./14 ft. lb.
260 in. lb./22 ft. lb.
300 in. lb./25 ft. lb.
 35 ft. lb.
 45 ft. lb.
 50 ft. lb.
 70 ft. lb.
 75 ft. lb.
100 ft. lb.
110 ft. lb.
140 ft. lb.
150 ft. lb.
200 ft. lb.
115 in. lb./10 ft. lb.
140 in. lb./12 ft. lb.
250 in. lb./21 ft. lb.
270 in. lb./23 ft. lb.
 35 ft. lb.
 40 ft. lb.
 55 ft. lb.
 75 ft. lb.
 80 ft. lb.
105 ft. lb.
125 ft. lb.
165 ft. lb.
180 ft. lb.
230 ft. lb.
245 ft. lb.
325 ft. lb.
165 in. lb./14 ft. lb.
200 in. lb./17 ft. lb.
350 in. lb./29 ft. lb.
 30 ft. lb.
 50 ft. lb.
 60 ft. lb.
 80 ft. lb.
105 ft. lb.
115 ft. lb.
165 ft. lb.
175 ft. lb.
230 ft. lb.
260 ft. lb.
330 ft. lb.
350 ft. lb.
470 ft. lb.
 14 ft. lb.
 17 ft. lb.
 29 ft. lb.
 35 ft. lb.
 58 ft. lb.
 69 ft. lb.
 98 ft. lb.
110 ft. lb.
145 ft. lb.
160 ft. lb.
200 ft. lb.
220 ft. lb.
280 ft. lb.
310 ft. lb.
490 ft. lb.
530 ft. lb.


How To Cut New Threads, the Correct and Professional Way | [Top of Page]

When cutting new threads in a drilled hole for a bolt, stud or screw, to prevent breaking off a [plug] tap in the hole (this can be a nightmare!), it's best to start the thread cutting process with a (preferably new) TAPER hand tap, then the threads can be cut deeper with a (preferably new) PLUG hand tap. If it's a blind hole (a hole that is blocked-off or not open at one end, such for mounting an exhaust header flange), the threads will go deeper with a plug tap for installation of the mounting bolt. (A through-hole is a hole that is open at either end, such as in plate steel.) And a BOTTOM hand tap is useful when the threads needs to go deeper than the plug tap can provide.

Refer to the Tap and Drill Chart below to find the correct size drill bit to use for any particular hole to be threaded. After drilling the hole, start the thread cutting process with a (preferably new) TAPER tap. For best thread cutting results, use WD-40 when cutting threads in aluminum, and use thread cutting oil, automatic transmission fluid (ATF) or power steering fluid (10 weight hydraulic oil) when cutting threads in cast iron or steel.

  1. To professionally create new threads, start the [taper] tap perpendicular, and not crooked (over to one side), with the hole. If a taper tap is mistakenly started crooked in the hole, in most cases, it'll straighten itself out with the hole as the cutting process continues. A plug tap may not do this.
  2. For a blind hole with right-hand threads, gently rotate the tap clockwise about 1/2 turn to cut the threads, then back it off counterclockwise about 1/4 turn. This will loosen and somewhat dislodge the metal cuttings from the flutes in the tap (open spaces between the cutting teeth). If the tap is difficult to back off, DO NOT FORCE IT, especially a small tap! Instead, with the tap in the hole, use (150± psi) compressed air to clear out the majority of the metal cuttings from the hole (wear safety glasses!), then GENTLY rotate the tap counterclockwise until it rotates freely and comes out of the hole. Again, use compressed air to clear out the metal cuttings from the hole.
  3. Gently and carefully cut the remaining threads until the tap bottoms out in the [blind] hole. Repeat step #2 several times for better results with a bigger tap, and less chance of breaking off a smaller tap in the hole. Use less muscle and more patience when working with smaller taps!
  4. Use caution and be aware of the depth of a blind hole when the tap bottoms out! If it's a shallow blind hole, judge by the hole's depth to determine where the tap will bottom out.
  5. Then use a (preferably new) PLUG hand tap, and repeat the 1/2 turn clockwise and 1/4 turn counterclockwise until the new threads are cut all the way in or through the hole. Return To Previous Paragraph or Website

Removing a Broken-Off Tap From a Hole - A threading tap that has broken off in an engine block or metal casting can be very difficult to remove. About all I can tell you is to either take your block to a reputable machine shop to have the tap removed, or go here and try to do it yourself: https://www.google.com/?gws_rd=ssl#q=removing+broken+tap+from+hole. Actually, before cutting new threads, it's ALWAYS best to use a TAPER hand tap, and clean out existing threads as the tapping process progresses. If used correctly, a TAPER tap is less likely to break off in the hole.


Tap and Drill Chart - Inch Sizes Only

To Tap These Size Threads Use This Size Drill Bit Closest Fractional or Number Size Decimal Inches
3-48 UNC #47 5/64" .0785"
3-56 UNF #45 - .0820"
4-40 UNC #43 3/32" .0890"
4-48 UNF #42 3/32" .0935"
5-40 UNC #38 - .1015"
5-44 UNF #37 - .1040"
6-32 UNC #35 7/64" .1100"
6-40 UNF #33 - .1130"
8-32 UNC #29 - .1360"
8-36 UNF #29 9/64" .1360"
10-24 UNC #25 5/32" .1495"
10-32 UNF #21 11/64" .1590"
12-24 UNC #16 11/64" .1770"
12-28 UNF #14 3/16" .1820"
1/4-20 UNC #7 13/64" .2010"
1/4-28 UNF #3 7/32" .2130"
5/16-18 UNC F 17/64" .2570"
5/16-24 UNF I - .2720"
3/8-16 UNC 5/16" 5/16" .3125"
3/8-24 UNF Q 21/64" .3320"
7/16-14 UNC U 23/64" .3680"
To Tap These Size Threads Use This Size Drill Bit Closest Fractional or Number Size Decimal Inches
7/16-20 UNF 25/64" 25/64" .3906"
1/2-13 UNC 27/64" 27/64" .4219
1/2-20 UNF 29/64" 29/64" .4531"
9/16-12 UNC 31/64" 31/64" .4844"
9/16-18 UNF 33/64" 33/64" .5156"
5/8-11 UNC 17/32" 17/32" .5312"
5/8-18 UNF 37/64" 37/64" .5781"
3/4-10 UNC 21/32" 21/32" .6562"
3/4-16 UNF 11/16" 11/16" .6875"
7/8-9 UNC 49/64" 49/64" .7656"
7/8-14 UNF 13/16" 13/16" .8125"
1.8 UNC 7/8" 7/8" .8750"
1.12 UNF 59/64" 59/64" .9219"
1-1/8-7 UNC 63/64" 63/64" .9844"
1-1/8-12 UNF 1-3/64" 1-3/64" 1.0469"
1-1/4-7 UNC 1-7/64" 1-7/64" 1.1094"
1-1/4-12 UNF 1 -11/64" 1-11/64" 1.1719"
1-3/8-6 UNC 1-7/32" 1-7/32" 1.2188"
1-3/8-12 UNF 1-19/64" 1-19/64" 1.2969"
1-1/2-6 UNC 1 -11/32" 1-11/32" 1.3438"
1-1/2"-12 UNF 1-27/64" 1-27/64" 1.4219"


Tap and Drill Bit Chart - Inch, Special Inch and Metric Sizes

To Tap These Size Threads Use This Size Metric, Letter, Number, Fractional or Decimal Size Drill Bit
0-80 UNF 3/64" / .0469"
1-64 UNC #53 / .0595"
1-72 UNF #53 / 1/16" / .0595"
2-56 UNC #50 / .0700"
2-64 UNF #50 / .0700"
3-48 UNC #47 / 5/64" / .0785"
3-56 UNF #45 / .0820"
4-36 NS (Special Size) #44 / .0860"
4-40 UNC #43 / 3/32" / .0890"
4-48 UNF #42 / 3/32" / .0935"
3-.060mm 2.5mm / .0984"
1/8-40 NS (Special Size) #38 / .1015"
5-40 UNC #38 / .1015"
5-44 UNF #37 / .1040"
6-32 UNC #35 / 7/64" / .1100"
6-36 NS (Special Size) #34 / .1110"
6-40 UNF #33 / .1130"
6-48 NS (Special Size) #31 / .1200"
4-0.70mm 3.4mm / #29 / .1338"
4-.075mm 3.4mm / #29 / .1338"
8-32 UNC #29 / .1360"
8-36 UNF #29 / 9/64" / .1360"
8-40 NS (Special Size) #28 / .1405"
3/16-24 NS (Special Size) #26 / .1470"
10-24 UNC #25 / 5/32" / .1495"
3/16-32 NS (Special Size) #22 / .1570"
10-32 UNF #21 / 11/64" / .1590"
5-.090mm (fine) 4.2mm / .1653"
5-.080mm (coarse) #16 / 4.3mm / .1693"
12-24 UNC 11/64" / .1770"
12-28 UNF #14 / 3/16" / .1820"
12-32 NEF #13 / .1850"
14-20 NS (Special Size) #10 / .1935"
1/4-24 UNC #7 / 13/64" / .2010"
14-20 NS (Special Size) #7 / .2010"
6-1.00mm (coarse) 5.2mm / #5 / .2047"
1/4-20 NS (Special Size) #4 / .2090"
1/4-28 UNF #3 / 7/32" / .2130"
1/4-32 NEF 7/32" / .2188"
1/4-40 NS (Special Size) #1 / .2280"
7-1.00mm (coarse) 6.1mm / 15/64" / .2401"
5/16-18 UNC F / 17/64" / .2570"
8-1.25mm (coarse) 6.9mm / 17/64" / .2716
5/16-24 UNF I / .2720"
8-1.00mm (fine) 7.1mm / .2795"
5/16-32 NEF 9/32" / .2812"
9-1.25mm (coarse) 7.9mm / 5/16" / .3110"
3/8-16 UNC 5/16" / .3125"
9-1.00mm (extra fine) 8.1mm / .3189"
9-0.75mm (fine) 8.3mm / 21/64" / .3268"
To Tap These Size Threads Use This Size Metric, Letter, Number, Fractional or Decimal Size Drill Bit
3/8-24 UNF Q / 21/64" / .3320"
10-1.50mm (fine) 8.7mm / 11/32" / .3425"
10-1.25mm (coarse) 8.9mm / 11/32" / .3503"
10-1.00mm (Spark Plug Tap) 9.1mm / .3583"
7/16-14 UNC U / 23/64" / .3680"
11-1.50mm (coarse) 9.7mm / .3818"
7/16-20 UNF 25/64" / .3906"
12-1.75mm (fine) 10.5mm / .4133"
12-1.50mm (coarse) 10.7mm / 27/64" / .4212"
1/2-13 UNC 27/64" / .4219
12-1.25mm (Spark Plug Tap) 10.9mm / 27/64" / .4291"
1/2-20 UNF 29/64" / .4531"
1/2-24 NS (Special Size) 29/64" / .4531"
14-2.00mm (coarse) 12.2mm / .4803"
9/16-12 UNC 31/64" / .4844"
14-1.50mm (fine) 12.7mm / 1/2" / .4999"
14-1.25mm (Spark Plug Tap) 12.8mm / 1/2" / .5039"
9/16-18 UNF 33/64" / .5156"
5/8-11 UNC 17/32" / .5312"
16-2.00mm (coarse) 14.2mm / 35/64" / .5590"
5/8-18 UNF 37/64" / .5781"
16-1.50mm (fine) 14.7mm / .5787"
11/16-11 NS (Special Size) 19/32" / .5938"
18-2.50mm (coarse) 15.8mm / 39/64" / .5220"
11/16-16 NS (Special Size) 5/8" / .6250"
3/4-10 UNC 21/32" / .6562"
18-1.50mm (Spark Plug Tap) 16.8mm / .6614"
3/4-16 UNF 11/16" / .6875"
20-2.50mm (coarse) 17.8mm / 11/16" / .7008"
7/8-9 UNC 49/64" / .7656"
7/8-14 UNF 13/16" / .8125"
22-1.50mm 20.9mm / .8228"
7/8-18 NS (Special Size)
(Spark Plug Tap)
53/64" / .8281"
24-3.00mm 21.4mm / 53/64" / .8425"
1.8 UNC 7/8" / .8750"
24-2.00mm 22.3mm / .8779"
1.12 UNF 59/64" / .9219"
1-14 NS (Special Size) 15/16" / .9375"
1-1/8-7 UNC 63/64" / .9844"
1-1/8-12 UNF 1-3/64" / 1.0469"
1-1/4-7 UNC 1-7/64" / 1.1094"
1-1/4-12 UNF 1-11/64" / 1.1719"
1-3/8-6 UNC 1-7/32" / 1.2188"
1-3/8-12 UNF 1-19/64" / 1.2969"
1-1/2-6 UNC 1-11/32" / 1.3438"
1-1/2"-12 UNF 1-27/64" / 1.4219"


National Pipe Tapered Tap Chart (Recommended tap drill to use for 75% thread depth.)
To Cut This Size Pipe Threads Use This Size Drill Bit / Closest Fractional / Decimal Inches Outside Diameter of Pipe
1/16-27 NPT D / 1/4" / .246" 0.313" (5/16")
1/8-27 NPT R / 11/32" / .339" 0.405" (13/32")
1/4-18 NPT 7/16" / .4375" 0.540" (35/64")
3/8-18 NPT 37/64" / .5781" 0.675" (43/64")
1/2-14 NPT 45/64" / .7031" 0.840" (27/32")
3/4-14 NPT 59/64" / .9219" 1.050" (1-3/64")
1-11 1/2 NPT 1-5/32" / 1.1562" 1.315" (1-5/16")
1-1/4-11 1/2 NPT 1-1/2" / 1.500" 1.660" (1-21/32")
1-1/2-11 1/2 NPT 1-47/64" / 1.7344" 1.900" (1-57/64")
2-11 1/2 NPT 2-7/32" / 2.2188" 2.375" (2-3/8")


Tap Chart for Metric Threads

Tap Size Basic Major Millimeter Diameter Basic Major Inch Diameter Millimeters Per Thread Millimeter Drill Bit Size Inch Drill Bit Size
M1.6 x 0.35 1.6mm .063" .35 1.25mm #55
M2 x 0.4 2mm .0787" .4 1.6mm #52
M2.5 x 0.45 2.5mm .0984" .45 2.05mm #46
M3 x 0.5 3mm .1181" .5 2.5mm #39
M3.5 x 0.6 3.5mm .1378" .6 2.9mm #32
M4 x 0.7 4mm .1575" .7 3.3mm #30
M5 x 0.8 5mm .1969" .8 4.2mm #19
M6 x 1 6mm .2362" 1 5mm #8
M8 x 1.25 8mm .315" 1.25 6.8mm H
M8 x 1 8mm .315" 1 7mm J
M10 x 1.5 10mm .3937" 1.5 8.5mm R
M10 x 1.25 10mm .3937" 1.25 8.8mm 11/32"
M11 x 1.5 11mm .433" 1.5 9.5mm 3/8"
M11 x 1.25 11mm .433" 1.25 9.75mm U
M12 x 1.75 12mm .4724" 1.75 10.2mm 13/32"
M12 x 1.25 12mm .4724" 1.25 10.8mm 27/64"
M14 x 2 14mm .5512" 2 12mm 15/32"
M14 x 1.5 14mm .5512" 1.5 12.5mm 1/2"
M16 x 2 16mm .6299" 2 14mm 35/64"
M16 x 1.5 16mm .6299" 1.5 14.5mm 37/64"
M18 x 2.5 18mm .7087" 2.5 15.5mm 39/64"
M18 x 1.5 18mm .7087" 1.5 16.5mm 21/32"
M20 x 2.5 20mm .7874" 2.5 17.5mm 11/16"
M20 x 1.5 20mm .7874" 1.5 18.5mm 47/64"
M22 x 2.5 22mm .8661" 2.5 19.5mm 49/64"
M22 x 1.5 22mm .8661" 1.5 20.5mm 13/16"
M24 x 3 24mm .9449" 3 21mm 53/64"
M24 x 2 24mm .9449" 2 22mm 7/8"
M27 x 3 27mm 1.063" 3 24mm 15/16"
M27 x 2 27mm 1.063" 2 25mm 1"


- Fractions, Numbers, Letters, Decimals and Metric Equivalents -
NOTE: There's three different type of drill bits - fraction, number and letter. Actually, there's four, including metric. Use the one that's closest to the size of hole that needs to drilled.

Fraction/|         |        | Fraction/|         |       | Fraction/|         |
 Number/ | Decimal |   MM   |  Number/ | Decimal |  MM   |  Number/ | Decimal |  MM
 Letter  |         |        |  Letter  |         |       |  Letter  |         |
----------------------------+----------------------------+----------------------------
  1/64"  =  .0156" =   .396 |  #20    =  .161"  =  4.089 |  T      =  .358"  =  9.093
  1/32"  =  .0312" =   .795 |  #19    =  .166"  =  4.216 | 23/64"  =  .3594" =  9.129
  #60    =  .040"  =  1.016 |  #18    =  .1659" =  4.214 |  U      =  .368"  =  9.347
  #59    =  .041"  =  1.041 | 11/64"  =  .1718" =  4.366 |  3/8"   =  .375"  =  9.525
  #58    =  .042"  =  1.067 |  #17    =  .173"  =  4.394 |  V      =  .377"  =  9.576
  #57    =  .043"  =  1.092 |  #16    =  .177"  =  4.496 |  W      =  .386"  =  9.804
  #56    =  .043"  =  1.092 |  #15    =  .180"  =  4.572 | 25/64"  =  .3906" =  9.921
  #55    =  .0465" =  1.181 |  #14    =  .182"  =  4.623 |  X      =  .397"  = 10.084
  3/64"  =  .0468" =  1.191 |  #13    =  .185"  =  4.699 |  Y      =  .404"  = 10.262
  #55    =  .052"  =  1.321 |  3/16"  =  .1875" =  4.763 | 13/32"  =  .4063" = 10.320
  #54    =  .055"  =  1.397 |  #12    =  .189"  =  4.801 |  Z      =  .413"  = 10.49
  #53    =  .0595" =  1.511 |  #11    =  .191"  =  4.851 | 27/64"  =  .4219" = 10.716
  1/16"  =  .0625" =  1.588 |  #10    =  .1935" =  4.915 |  7/16"  =  .4375" = 11.113
  #52    =  .0635" =  1.613 |  #9     =  .196"  =  4.978 | 29/64"  =  .4531" = 11.509
  #51    =  .067"  =  1.701 |  #8     =  .199"  =  5.055 | 15/32"  =  .4688" = 11.908
  #50    =  .070"  =  1.778 |  #7     =  .201"  =  5.105 | 31/64"  =  .4844" = 12.304
  #49    =  .073"  =  1.854 | 13/64"  =  .2031" =  5.159 |  1/2"   =  .500"  = 12.700
  #48    =  .076"  =  1.930 |  #6     =  .204"  =  5.182 | 33/64"  =  .5156" = 13.096
  5/64"  =  .0781" =  1.984 |  #5     =  .2055" =  5.22  | 17/32"  =  .5312" = 13.495
  #47    =  .0785" =  1.994 |  #4     =  .209"  =  5.309 | 35/64"  =  .5469" = 13.891
  #46    =  .081"  =  2.06  |  #3     =  .213"  =  5.41  |  9/16"  =  .5625" = 14.288
  #45    =  .082"  =  2.083 |  7/32"  =  .2188" =  5.558 | 37/64"  =  .5781" = 14.684
  #44    =  .086"  =  2.184 |  #2     =  .221"  =  5.613 | 19/32"  =  .5938" = 15.083
  #43    =  .089"  =  2.26  |  #1     =  .228"  =  5.791 | 39/64"  =  .6094" = 15.479
  #42    =  .0935" =  2.375 |  A      =  .234"  =  5.943 |  5/8"   =  .625"  = 15.875
  3/32"  =  .0937" =  2.383 | 15/64"  =  .2344" =  5.954 | 41/64"  =  .6406" = 16.271
  #41    =  .096"  =  2.438 |  B      =  .238"  =  6.045 | 21/32"  =  .6563" = 16.67
  #40    =  .098"  =  2.489 |  C      =  .242"  =  6.147 | 43/64"  =  .6719" = 17.066
  #39    =  .0995" =  2.527 |  D      =  .246"  =  6.248 | 11/16"  =  .6875" = 17.463
  #38    =  .1015" =  2.578 |  1/4"   =  .250"  =  6.35  | 45/64"  =  .7031" = 17.859
  #37    =  .104"  =  2.642 |  E      =  .250"  =  6.35  | 23/32"  =  .7188" = 18.254
  #36    =  .1065  =  2.705 |  F      =  .257"  =  6.528 | 47/64"  =  .7344" = 18.654
  7/64"  =  .1094" =  2.779 |  G      =  .261"  =  6.629 |  3/4"   =  .750"  = 19.05
  #35    =  .110"  =  2.794 | 17/64"  =  .2656" =  6.746 | 49/64"  =  .7656" = 19.446
  #34    =  .111"  =  2.819 |  H      =  .266"  =  6.756 | 25/32"  =  .7813" = 19.845
  #33    =  .113"  =  2.87  |  I      =  .272"  =  6.909 | 51/64"  =  .7969" = 20.241
  #32    =  .116"  =  2.946 |  J      =  .277"  =  7.036 | 13/16"  =  .8125" = 20.638
  #31    =  .120"  =  3.048 |  K      =  .281"  =  7.137 | 53/64"  =  .8282" = 21.034
  1/8"   =  .125"  =  3.175 |  9/32"  =  .2813" =  7.145 | 27/32"  =  .8438" = 21.433
  #30    =  .1285" =  3.195 |  L      =  .290"  =  7.366 | 55/64"  =  .8594" = 21.821
  #29    =  .136"  =  3.454 |  M      =  .295"  =  7.493 |  7/8"   =  .875"  = 22.225
  #28    =  .1405" =  3.569 | 19/64"  =  .2969" =  7.541 | 57/64"  =  .8906" = 22.621
  9/64"  =  .1406" =  3.571 |  N      =  .302"  =  7.671 | 29/32"  =  .9063" = 23.020
  #27    =  .144"  =  3.658 |  5/16"  =  .3125" =  7.938 | 59/64"  =  .9219" = 23.416
  #26    =  .147"  =  3.734 |  O      =  .316"  =  8.026 | 15/16"  =  .9375" = 23.813
  #25    =  .1495" =  3.797 |  P      =  .323"  =  8.204 | 61/64"  =  .9532" = 24.209
  #24    =  .152"  =  3.861 | 21/64"  =  .3281" =  8.334 | 31/32"  =  .9688" = 24.608
  #23    =  .154"  =  3.912 |  Q      =  .332"  =  8.433 | 63/64"  =  .9844" = 25.004
  5/32"  =  .1563" =  3.970 |  R      =  .339"  =  8.611 |     1"  = 1.000"  = 25.400
  #22    =  .157"  =  3.988 | 11/32"  =  .3438" =  8.733 |
  #21    =  .159"  =  4.039 |  S      =  .348"  =  8.839 |


Small Screw Size and Maximum Diameter of Threads

Thread Size

Maximum Screw Diameter

Actual O.D. Thread Diameter Closest Drill Bit Size Closest Millimeter Size
2-56 .086" #44 / 3/32"

2.184mm

3-48 .099" #39 / 7/64" 2.5mm
4-40 .112" #33 or #34 2.84mm
5-40 .125" 1/8" 3.175mm
6-32 .138" 9/64" 3.5mm
8-32 .164" 11/64" 4.17mm
10-24 .190" 3/16" 4.8mm
10-32 .190" 3/16" 4.8mm
12-24 .216" 7/32" 5.5mm


- Metric Equivalents to Decimals of an Inch -

      Decimals of |        Decimals of   |       Decimals of
 MM     an inch   | MM       an inch     | MM      an inch
------------------+----------------------+--------------------
  .1 =  .00394"   |  1.  =  .03937"      | 15.  =  .59055"
  .2 =  .00787"   |  2.  =  .07874"      | 16.  =  .62992"
  .3 =  .01181"   |  3.  =  .11811"      | 17.  =  .66929"
  .4 =  .01575"   |  4.  =  .15748"      | 18.  =  .70866"
  .5 =  .01968"   |  5.  =  .19685"      | 19.  =  .74803"
  .6 =  .02362"   |  6.  =  .23622"      | 20.  =  .78740"
  .7 =  .02756"   |  7.  =  .27559"      | 21.  =  .82677"
  .8 =  .03149"   |  8.  =  .32496"      | 22.  =  .86614"
  .9 =  .03543"   |  9.  =  .35433"      | 23.  =  .90551"
10.  =  .3937"    | 12.7 =  .500"        | 24.  =  .94488"
11.  =  .43307"   | 13.  =  .51181"      | 25.  =  .98425"
12.  =  .47244"   | 14.  =  .55118"      | 25.4 = 1.000"


Sheet Metal Thickness Gauges (All dimensions in inches.)
Gauge Standard Steel Galvanized Steel Aluminum Gauge Standard Steel Galvanized Steel Aluminum
3 0.2391" - 0.2294" 20 0.0359" 0.0396" 0.0320"
4 0.2242" - 0.2043" 21 0.0329" 0.0366" 0.0285"
5 0.2092" - 0.1819" 22 0.0299" 0.0336" 0.0253"
6 0.1943" - 0.1620" 23 0.0269" 0.0306" 0.0226"
7 0.1793" - 0.1443" 24 0.0239" 0.0276" 0.0201"
8 0.1644" - 0.1285" 25 0.0209" 0.0247" 0.0179"
9 0.1495" 0.1532" 0.1144" 26 0.0179" 0.0217" 0.0159"
10 0.1345" 0.1382" 0.1019" 27 0.0164" 0.0202" 0.0142"
11 0.1196" 0.1233" 0.0907" 28 0.0149" 0.0187" 0.0126"
12 0.1046" 0.1084" 0.0808" 29 0.0135" 0.0172" 0.0113"
13 0.0897" 0.0934" 0.0720" 30 0.0120" 0.0157" 0.0100"
14 0.0747" 0.0785" 0.0641" 31 0.0105" 0.0142" 0.0089"
15 0.0673" 0.0710" 0.0571" 32 0.0097" 0.0134" 0.0080"
16 0.0598" 0.0635" 0.0508" 33 0.0090" - 0.0071"
17 0.0538" 0.0575" 0.0453" 34 0.0082" - 0.0063"
18 0.0478" 0.0516" 0.0403" 35 0.0075" - 0.0056"
19 0.0418" 0.0456" 0.0359" 36 0.0067" - -


A-1 Miller's Computerized Stuska Water Brake Engine Dynamometer (Dyno) Service with DPM Data Logger Software to Test Horsepower and Torque! | [Top of Page]

For performance testing of 10-16hp single cylinder Kohler stock or competition pulling engines at speeds up to 12,000 RPM. 100% accurate, customers can rent dyno time, fine tune and make adjustments or changes to their engines to gain maximum horsepower and torque, and print-out the results so their tractor(s) will be truly competitive on the track. With an engine dyno, the puller can adjust their engine to get maximum horsepower and torque, and gear their tractor appropriately to have an advantage over the competition. NOTE: A fresh-built engine may not produce full power until it's broke-in. This is when the valves wear-in with the seats to completely seal in the compression. The rings will likely hold the compression, but the valves may leak slightly until they wear into the seats. This is normal for all engines and may take several hours or pulls to happen, then the valves will be able to hold full compression. Lots of pullers tell A-1 Miller's after I've built their engines that it seems to pull stronger every time they pull it.

Engine Dyno Rental Fee: $50.00 per hour run time from the moment the engine is started. No setup fee for Cub Cadet engines with a 3- or 6-pin/stud clutch driver. An adapter may need to be needed or fabricated for other makes and models of engines. Only engines with the narrow base oil pan can be tested. Engines with the wide base (tall) oil pan cannot be tested at this time. [Return to Previous Section, Paragraph or Website]


Coming Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back and Self-Propelled Garden Tractor Pulling Sled. FYI - The professionally-built self-propelled pulling sled is the only one I've ever built (click the picture to the right to see a larger image of this sled), and I got it right the first time, with very few changes or modifications that had to be made to it. I guess I'm just one of those kind of guys that knows what he's doing. Pullers really like pulling our sled, too. They say it's the best sled they've ever pulled. (Not bragging, just stating a fact.) By the way - Track Master sled is engineered so well (by Brian Miller), that other sled builders/owners have copied my well thought-out and proven design. And I do appreciate them acknowledging my intelligence. Anyway, I have lots of work to do in my shop and I work on the sled plans in my spare time. As soon as my plans with an inventory list of parts to use are perfected, I'll post the update in my websites with the prices of the plans. Remember - Perfection takes time. If it's worth having, it's worth waiting for. Also, I plan to acquire a bigger shop and may build high quality garden tractor pulling sleds in the future to offer for sale. Please call 573-256-0313 (shop) or 573-881-7229 (cell; text or voice message), or email pullingtractor@aol.com if interested. - Brian Miller


To place an order and/or for FREE professional and honest technical assistance and support, please contact:

A-1 Miller's Performance Enterprises | 1501 W. Old Plank Rd. | Columbia, MO (Missouri) 65203-9136 USA | Phone: 1-573-256-0313 (shop) | 1-573-881-7229 (cell; text or when leaving a voice message, please speak slowly and clearly). Please call Monday-Friday, except holidays, 9am to 5pm, Central time zone. If no answer, please try again later. (When speaking with Brian, please be patient because I stutter.) E-mail: pullingtractor@aol.com. When you call, text, email or visit our shop, you will be dealing directly with the owner for the best customer service. A-1 Miller's shop is open to the public from 9am to 5pm, including weekends, except holidays. Please call before coming so I'll be here waiting for your arrival. Directions to our shop | 1501 West Old Plank Road, Columbia, MO - Google Maps or Map of 1501 West Old Plank Road, Columbia, MO by MapQuest. If you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's shop to personally drop off and/or pick up your carburetor, clutch assembly, engine, transaxle, tractor, etc. "The road to a friend's house (or shop) is never long." (We're planning to relocate to other property with a bigger and better shop so we can provide many more high quality parts and professional services.)

To place an order, please call the number below Ê or send an email with your name, complete and correct postal address and phone number and so I can figure the total with shipping cost and USPS Tracking. For payment options for parts ordered or services performed, or to make a donation to my websites, I accept cash (in person), USPS Postal Money Orders, cashier's checks, business checks, MasterCard, VISA, Discover, American Express (please add 2.5% to the total for the credit/debit card processor's surcharge), Western Union Money Transfer or MoneyGram Money Transfers. (If a part for a specific purpose is special ordered, your debit/credit card may be charged for the full amount or as a deposit right after your order is placed; please do not send your debit/credit card information in email!) Or you can pay A-1 Miller's through PayPal. (My PayPal account name is my email address. And be sure to mention in PayPal a description of what the payment is for.) If sending a money order, please include a note in the envelope with your name, complete and correct postal address, phone number and a description of what the payment is for. My mailing address and phone number are below Ê . I'll make a note of your order, and I may have to order some of the parts, which should take a few days to come in, but I will send the parts to you as soon as I have everything in stock after I receive your payment.

IMPORTANT - When sending your part(s) to A-1 Miller's for rebuilding or repair, package everything securely so the item(s) won't get damaged in shipping and please include a note in the box with your name, mailing address, phone number (in case I have any questions) and a description of what you want done. When shipping heavy parts, it's best to put a slightly smaller box inside a larger box, to double the strength and integrity of the package. Because the clumsy "gorillas" or incompetent and uncaring workers that work for certain delivery services mishandle the heavy packages and don't care. And when the work is completed, I'll either call or email you an invoice with the total including shipping & handling.

To figure the shipping cost, I weigh the package with the parts, then I go online to the USPS Postage Rate Calculator website. I type in the weight, my zip code and your zip code, then it shows A-1 Miller's the prices for various ways to ship the package. I always choose US Postal Service because I believe that's the most fastest, economical and reliable method.

Shipping: (United States and it's territories)
To save you shipping charges, item(s) in a package or cushioned envelope weighing less than 13 oz. is sent by First Class Mail for a 2-6 day delivery. Most packaged item(s) weighing over 13 oz. is sent by US Priority Mail for a 2-3 day delivery. To save you even more on shipping heavy items, I always try to use the US Postal Services' Flat Rate Priority Mail envelope and boxes (if the item(s) can fit inside the envelope or boxes). Some heavy items weighing no more than 70 lbs. is sent by US Mail Parcel Post. Item(s) weighing over 70 lbs. is sent by FedEx Ground. Again, if you're the kind of person who don't trust delivery/shipping companies (mis)handling your high-dollar and fragile merchandise, you can make the long drive to A-1 Miller's shop to personally drop off and/or pick up your engine, transaxle, tractor, etc.

We Ship to Canada and Worldwide -
Item(s) in a package or cushioned envelope weighing less than 1 lb. is sent by US Postal Service Airmail Letter Post for a 4-7 days delivery. Packaged item(s) weighing over 1 lb. and up to 66 lb. is sent by US Postal Service Airmail Parcel Post for a 4-10 days delivery. I cannot use the US Postal Services' Flat Rate Priority Mail envelopes and boxes to ship outside U.S. territories. Item(s) weighing over 67 lbs. or more is sent by FedEx Ground or equivalent services. We try to keep our shipping cost to customers within reason. Therefore, we don't ship our products in a fancy-looking package with our company name and/or logo on it because most customers will just toss it in the trash after they remove the contents.


We Accept PayPal, Visa, MasterCard, American Express & Discover Credit & Debit Cards
(When placing an order through PayPal, please provide a list of which parts you need.)

To make a payment to A-1 Miller's through PayPal, go to PayPal's secure website ( https://www.paypal.com/ ) and click on Send and Request -> Pay for goods or services. Type in my email address, or copy and paste this: pullingtractor@aol.com, the amount and follow the directions. Be sure to mention in PayPal a description of what the payment is for. After you've finished, PayPal will send A-1 Miller's an email notifying me that you have made a payment to A-1 Miller's for the product(s) or services and amount entered. Then I go to their website and direct PayPal to deposit the money in my bank account. And I will send the parts to you as soon as I receive your payment. But I may have to order some of the parts if they're not in stock, which should take a few days. In that case, I will send you the parts as soon as they come in. PayPal protects your financial privacy and security. With PayPal, privacy is built in. It's a way for you to pay without exposing their financial information.


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