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Copyright © 1996-Present. This website created, designed and maintained by Brian Miller.

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

Where Science and Common Sense Come Together for Better Performance
A-1 Miller's Performance Enterprises - Parts & Services Online Catalog | Hot Rod Garden Tractor and Mini-Truck Pullers Association (Reorganized)

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Using a Quality-Made Hitch with an Adjustable Drawbar on a Garden Pulling Tractor or Mini-Rod | Updated 1/5/16 Top of page

First of all, when a pulling association's or club's sanctioning rules state that "the tractor shall have no more than a 13" hitch height", this is worded wrong. It should read: "The tractor shall have no more than a 13" drawbar height." The "drawbar" is the part where the hook (on the sled) fastens to. And the "hitch" is the framework that's attached to the rear of the tractor. It contains the drawbar.

If you can keep from doing so, don't use a bolted-on-solid hitch with a non-adjustable drawbar or a one-piece, welded-on drawbar. It's not that the weld may break, but if you had change the drawbar height, choose to pull in another class or with another club that require a different drawbar height, or if you were to change tire size, deflate/inflate tire pressure, change the diameter of the front tires or as the rear tires wear, a hitch with an adjustable drawbar, you can easily and quickly reset the drawbar height accordingly. This will give your tractor a better advantage with the competition.

To be truly competitive, always run the highest drawbar height your clubs' rules allow. And the further rearward the drawbar is located, the more weight must be placed on the front of the tractor. But if the drawbar is too close to the rear axle, it'll be hard to control the front end from rearing up and down violently at times. Therefore, the best position for the drawbar is 6-1/2" to 8" rearward from the center of the rear axle. This should allow the front of the tractor to rise gently (if the tractor is weighted correctly), which should give the driver full control of the tractor. This measurement applies to all makes and models of garden tractors and for all classes of pulling tractors, from a basic stock to a fully modified.

Information Concerning Strength and Safety of the Pulling Hitch and Adjustable Drawbar Ê

When certain pulling club's sanctioning rules state something like, "the pulling point may not be more than 3/4 inches in depth," what they actually mean is, on the drawbar, there must be no more (and no less, for strength) than 3/4" of metal between inside rear of the hole and outside rearward edge of the drawbar.

Also, for strength and safety, and because most rules don't bother mentioning this, the drawbar itself should be made of minimum 1/2" thickness steel, and not aluminum!

But the upper and lower angle brackets should be made of either minimum 1/8" thickness mild steel or minimum 1/4" thickness 6061 aluminum.

How to Construct a Professional Pulling Hitch with an Adjustable Drawbar Ê

FYI: This entire assembly is called the HITCH. The adjustable flat bar where the hook goes is called the DRAWBAR.

This type of garden tractor pulling hitch with an adjustable drawbar is the most common and strongest ever used. It's low-cost and looks nice, too. It's the design that most professional pullers use, plus it's NQS legal. It will adapt to virtually any garden tractor as long as two pieces of angled steel can be fastened on the rear.

Specifications are:

How to Prevent the IH Cub Cadet Mechanical PTO Clutch/Starter Pulley from Loosening on the Crankshaft (Updated 3/17/15) Top of page

Tools and parts required are: Drill press (or milling machine for better accuracy), 5/16" drill bit (or 5/16" countersink bit for better accuracy), 1/4" transfer punch, two 5/16-18 UNC x 5/8" length Allen set screws, and two 5/16-18 UNC jam nuts.

  1. Remove the pulley from the crankshaft. Be careful not to bend or damage it in any way.
  2. Remove the OEM set screws from the pulley and the keystock from the crankshaft. Set them aside for another project. They won't be needed for this fix.
  3. Reinstall the pulley on the crankshaft, position the outer edge of the hub exactly 1-1/8" from the end of the crankshaft, install one of the 5/8" length Allen set screws in the hub with the keyway and tighten it in the keyway slot.
  4. Going through the other set screw hole (that's located at the 3:00 position or 90° of the keyway slot), use the 1/4" transfer punch to place a mark on the crankshaft dead center of the hole. Don't go by the original indention mark on the crankshaft that the OEM set screw made, because if the pulley was loose, the indention may not be dead center with the hole.
  5. Remove the pulley and use the 5/16" drill bit and drill press to create an 1/8" deep hole (dimple) dead center of the punch mark.
  6. Reinstall the pulley on the crankshaft, install a 5/8" length Allen set screw in the hub and tighten it securely into the drilled hole.
  7. Install the other 5/8" length Allen set screw in the keyway slot and tighten it securely.
  8. Install the jam nuts on the set screws and tighten them securely to prevent the set screws (and pulley) from loosening overtime. NOTE: The 5/8" length set screws and jam nuts are short enough to not make contact with the pressure plate on the PTO clutch assembly.

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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). 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.) 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. E-mail: pullingtractor@aol.com. 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 parts and services.) Please click here to place an order.
IH Cub Cadet Garden Tractor Mechanical PTO Clutch Rebuild Kit. Fits Cub Cadet models 70, 71, 72, 73, 86, 100, 102, 104, 105, 106, 107, 108 (serial number 481999 & below), 109 (serial number 481999 & below), 122, 123, 124, 125, 126, 127, 128 (serial number 481999 & below), 129 (serial number 481999 & below) and 147. OEM Cub Cadet part # 759-3490. $87.00 each, plus shipping & handling. IH Cub Cadet Garden Tractor Mechanical PTO Clutch Rebuild Kit. Fits Cub Cadet models 86, 108, 109, 128 (serial number 482000 & up), 129 (serial number 482000 & up), 149 (serial number 481999 & below) and 169. Install both pressure springs to prevent clutch slippage. OEM Cub Cadet part # 759-3489. $90.00 each, plus shipping & handling.
Carbon Button for IH Cub Cadet Garden Tractor Mechanical PTO Clutch. OEM Cub Cadet part # IH-473483-R2. $7.80 each, plus shipping & handling. Metal Button for IH Cub Cadet Garden Tractor Mechanical PTO Clutch. OEM Cub Cadet part # IH-473477-R3. $10.75 each, plus shipping & handling.
New Insert Bearing with Eccentric Locking Collar for IH Cub Cadet Garden Tractor Mechanical PTO Clutch. Each kit includes set screw and jam nut. Bearing size: 1" i.d. x 2.04" o.d. Fits all IH Cub Cadet with a mechanical PTO clutch.
  • High quality aftermarket. Our part # 150545. $20.00 each, plus shipping & handling.
  • OEM Cub Cadet part #'s IH-60071-C92 (bearing) and IH-455102-R21 (locking collar). $42.70 each, plus shipping & handling.
Clutch/Starter Pulley for IH Cub Cadet Garden Tractor Mechanical PTO Clutch.
  • Used and in excellent condition. $75.00 each, plus shipping & handling.
  • OEM Kohler part # 231591-S. $122.70 each, plus shipping & handling.
  • OEM Cub Cadet part # KH-231591. $162.00 each, plus shipping & handling.

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 chart(s) below Ê for the correct size drill bit for the 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) #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) #38 / .1015"
5-40 UNC #38 / .1015"
5-44 UNF #37 / .1040"
6-32 UNC #35 / 7/64" / .1100"
6-36 NS (Special) #34 / .1110"
6-40 UNF #33 / .1130"
6-48 NS (Special) #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) #28 / .1405"
3/16-24 NS (Special) #26 / .1470"
10-24 UNC #25 / 5/32" / .1495"
3/16-32 NS (Special) #22 / .1570"
10-32 UNF #21 / 11/64" / .1590"
5-.090mm 4.2mm / .1653"
5-.080mm #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) #10 / .1935"
1/4-20 UNC #7 / 13/64" / .2010"
14-24 NS (Special) #7 / .2010"
6-1.00mm 5.2mm / #5 / .2047"
1/4-24 NS (Special) #4 / .2090"
1/4-28 UNF #3 / 7/32" / .2130"
1/4-32 NEF 7/32" / .2188"
1/4-40 NS (Special) #1 / .2280"
7-1.00mm 6.1mm / 15/64" / .2401"
5/16-18 UNC F / 17/64" / .2570"
8-1.25mm 6.9mm / 17/64" / .2716
5/16-24 UNF I / .2720"
8-1.00mm 7.1mm / .2795"
5/16-32 NEF 9/32" / .2812"
9-1.25mm 7.9mm / 5/16" / .3110"
3/8-16 UNC 5/16" / .3125"
9-1.00mm 8.1mm / .3189"
9-0.75mm 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 8.7mm / 11/32" / .3425"
10-1.25mm 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 9.7mm / .3818"
7/16-20 UNF 25/64" / .3906"
12-1.75mm 10.5mm / .4133"
12-1.50mm 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) 29/64" / .4531"
14-2.00mm 12.2mm / .4803"
9/16-12 UNC 31/64" / .4844"
14-1.50mm 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 14.2mm / 35/64" / .5590"
5/8-18 UNF 37/64" / .5781"
16-1.50mm 14.7mm / .5787"
11/16-11 NS (Special) 19/32" / .5938"
18-2.50mm 15.8mm / 39/64" / .5220"
11/16-16 NS (Special) 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 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)
(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) 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 Outside Diameter of Pipe Use This Size Drill Bit Closest Fractional Decimal Inches
1/16-27 NPT 0.313" (5/16") D 1/4" .246"
1/8-27 NPT 0.405" (13/32") R R or 11/32" .339"
1/4-18 NPT 0.540" (35/64") 7/16" 7/16" .4375"
3/8-18 NPT 0.675" (43/64") 37/64" 67/64" .5781"
1/2-14 NPT 0.840" (27/32") 45/64" 45/64" .7031"
3/4-14 NPT 1.050" (1-3/64") 59/64" 59/64" .9219"
1-11 1/2 NPT 1.315" (1-5/16") 1-5/32" 1-5/32" 1.1562"
1-1/4-11 1/2 NPT 1.660" (1-21/32") 1-1/2" 1-1/2" 1.5000"
1-1/2-11 1/2 NPT 1.900" (1-57/64") 1-47/64" 1-47/64" 1.7344"
2-11 1/2 NPT 2.375" (2-3/8") 2-7/32" 2-7/32" 2.2188"

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 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" - -

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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). 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.) 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. E-mail: pullingtractor@aol.com. 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 parts and services.) Please click here to place an order.

A-1 Miller's Fully Computerized Stuska Water Brake Engine Dynamometer (Dyno) Service with DPM Data Logger Software!

For performance testing engines up to 200hp at speeds up to 12,000 RPM. The only engine dyno service in Missouri for Kohler pulling engines! Fully operational and 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 me 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.

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). 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.) 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. E-mail: pullingtractor@aol.com. 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 parts and services.) Please click here to place an order.

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, MoneyGram Money Transfers or Popmoney. (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 me 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 me 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 me 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 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 me 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 me an email notifying me that you have made a payment to me 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.

Coming Soon - Detailed Illustrated Plans on How to Construct a Professional Pull-Back Garden Tractor Pulling Sled, and a Self-Powered Garden Tractor Pulling Sled. FYI - My professionally-built self-powered pulling sled, Track Master (click the picture to the right to see a larger image of my sled), is the only one I've ever built and I got it right the first time, with very few changes 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 my sled, too. They say it's the best sled they've ever pulled. (Not bragging, just stating the truth.) 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. 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. Remember - Perfection takes time. If it's worth having, it's worth waiting for. Also, I plan to acquire a bigger shop and I may build high quality garden tractor pulling sleds in the future to offer for sale. Please call me at 573-256-0313 (shop) or 573-881-7229 (cell), or email me at pullingtractor@aol.com or pullingtractor@yahoo.com if you're interested. - Brian Miller

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