Threading cutting calculations part 1

This is a ballpark figure to calculate thread depth. I had forgoten to mention, be sure to touch off your tool carefully and accuratly. A deep touchoff or starting point will potentially cut your pitch dia. too deep. I also neglected to say this calculation is for single depth. If your machine has 1 for .001 dials you have to double the sum of your equation. An evan simpler equation is .866 divided by # of threads Ex: 1/2-13= .866 / 13= .066 Dont forget the -.005

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• lathe
• threading
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• threads
• measuring
• machine
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• southbend
• single
• point
• manual
• machining
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• brigeport
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[joleenmorganjohn]

@Thinker4Life I'm honestly to lazy to do all the math to calculate wires over threads. The kit makes things easy.

You cant substitute M3 wire and mutiply by 12 the numbers dont come out right. If you are indeed talking about a pitch of .4 my wire kit doesnt go down to .4 pitch That would be a real oddball size. You will have to address the machinery's handbook on that one. I hope all this helps you. Take your time check with the nut often.Try a scrap peice first make sure the #'s jive.

[joleenmorganjohn]

@Thinker4Life I would personally make the bolt 35.924mm for a little clearence. If you dont have 2.3368mm dia. wires you can make them but they have to be dead nuts right to size. A spin fixture on the surface grinder could acheive the accuracy needed. If the boss wants measurment over wires then tell him to part with the $20 for a set. There is calculations to figure different wire sizes for the same thread. But the 2.3368mm is the best size for that pitch.

[joleenmorganjohn]

@Thinker4Life Thanks for watching. This will be a mouthful to explain. Difference with metric is to mutiply. .866 X pitch Ex: .866 X 4= 3.464mm that is the depth of your thread. Tell your boss to order the thread wire kit for you. A M36 x 4 bolt has a pitch diameter of 33.4019mm depending on the class tolerence. If you use a wire diameter of 2.3368mm (.092 inches) you want a measurment over the wires of 36.9483mm. These set of wires is in the kit.

[Thinker4Life]

Work for Metric? I'm trying to find info on checking a ( M36 x .4 ) I guess after I cut I could just blue up the nut and thread it on and look for good surface contact but the boss would like me to mare accuratly check it using pins/wires. I can only find wire charts that go up to M6. I am curious if I can take the M3 wire size and just miltiply it by 12 for the correct wire size but im new to the Lathe and I don't even know what dimention im looking for to mic over the 3 pins/wires? Any help?

[joleenmorganjohn]

@TheKelstr Glad to here you were able to save some time. Hope to have some more cheats uploaded soon. Nothing ground breaking mind you. Just little tid bits. Been real buisy though. Thanks for watching!

[TheKelstr]

Thanks for this tip, I have been in the biz for 40 years and own my own race shop.

I had to do some threading last week on many different componets and i used your easy numbers and they worked perfect every time ,

It was way faster than my old Trig equasion I used to do , ---