How do I measure thread size?

[wavinwayne]

Originally Posted By: moribundman
Well, Major Tom, I happen to be looking for a few brass set screws (Let's say they are really bolts, but they are not called "set bolts") in this metric size:

1.2 mm diameter, 2.4 mm long (without head), 0.2 mm pitch. Where can I find those?

How'd you get that to balance on your head?

 

[mpvue]

Originally Posted By: moribundman
Originally Posted By: tdi-rick
Mori, counting the threads doesn't help if it's a metric bolt, and I've never heard the pitch expressed as a fraction on imperial hardware, it's always 1" x 8 (tpi), as it does in my tapping charts and tap and tools catalogues.

If the OP can, take the fastener to the hardware or tool shop and match it by laying it on top of the tap.


The OP didn't say if it was a metric or SAE bolt.

A metric bolt has either a fine or coarse thread, and the pitch is the distance between threads in mm. ON SAE fasteners, the thread pitch per se isn't used but "threads per inch" instead.

On my bike there are bolts that are SAE and metric, and some of either go by pitch or TPI. I had the hardest time finding very specific axle nuts with a rotating locking washer that are metric but use TPI.

the bicycle industry used to be the worst for this!french, english and italian threads! Japanese rear axles are 10x1 (easy-10mm dia by 1 thread per mm)'english' solid axles are 3/8 x 26tpi (but coaster brake axles are 3/8 x 24tpi).
the WORST though was Campagnolo axles- 10 by 26; YES, 10mm dia x 26 TPI!

front campy is 9 x 26.
sorry to go off track.

 

[NJC]

Originally Posted By: mpvue
the WORST though was Campagnolo axles- 10 by 26;

Could this have been a 1mm thread pitch? It's only .00085" different than 26 tpi.

 

[mpvue]

Originally Posted By: NJC
Originally Posted By: mpvue
the WORST though was Campagnolo axles- 10 by 26;

Could this have been a 1mm thread pitch? It's only .00085" different than 26 tpi.

it's enough to not work. campy axles need campy hardware.

 

[moribundman]

Originally Posted By: eljefino
That a head bolt for a chinese motorized bike engine?

Do you need merely mechanically similar ones or is this finish work that has to look nice?

I found these guys but they don't look like what you want.


Only the head has to look nice. The rest can be ugly. The tip needs to be perfect, because it contacts a rotating part. I know the place you linked. My local hobby shop has more suitable hardware. I have a feeling I'll end up making my own set screws.

 

[tdi-rick]

Originally Posted By: moribundman

I have a feeling I'll end up making my own set screws.


God, you'll have fun making those

 

[moribundman]

Originally Posted By: tdi-rick
Originally Posted By: moribundman

I have a feeling I'll end up making my own set screws.


God, you'll have fun making those

At least Papa Bear will offer giving me his tiny nuts from 1954.

 

[Papa Bear]

You rang....

 

[moribundman]

After all the ringing you've been doing, I'll be returning the favor.

 

[alreadygone]

I thought even mildly manly men kept a jelly (or peanut butter) jar sitting in a shelf/cabinet with every leftover, borrowed, picked up off the street, etc. nut gathered since puberty, just to use as guages when the need arose to find the size of nutless threaded stuff!!

Bob

 

[moribundman]

Bob, what are you calling Second Monkey?

 

[mcshooter]

you got to be kidding me, any guy on this web site that does not have tread pitch gages...

 

[moribundman]

"Tread pitch gages?" John Browing, have you returned?

 

[NJC]

 

[Pablo]

Good one. Guy sets out to show his manhood tool superiority and it remains flaccid due lack of proper fingering.

I have some common pitch gages from way back, but those are pretty useless, because all the common thread sizes are pretty easy to ID!!

If it's some oddish size, nothing wrong with whipping out the caliper, or precision scale. Mori showed you how. Can be tough on blind females though. Fairly useless with NPT as well. But those are also easy to learn and spot the taper.....most rookies mix up 1/8" and 1/4" NPT. 1/2" and up, simple pie.

And lastly yes, if it's pocket size and I need to go to the hardware store anyway, I just do the safety fit up at the store. Just make sure the bins are labeled correctly!

 

[1sttruck]

Who doesn't have a set of tap and dies of SAE coarse and fine, metric coarse and fine, plus Whitwirth and British Standard, and a lathe to cut custom threads ?

(I just have a set of SAE and metric taps, a few dies, and pine for a lathe plus room to put one in :^)

 

[mcshooter]

sorry about that moribundman, but i have 35 years as a machinest and still have access to 2 complete shops but if you dont check out emachine, when you download it you can use there post and design any parts you need . its simple, you spec out the material, machine, and design and it will give you cost and shipping date.