Thread: How do I work out what thread it is?

This is probably a stupid question, but here goes...

Let's say I have an external threaded item (eg a threaded stud) on a machine/tool but the internal threaded item (eg a nut) is missing. How do I go about working out what thread I will need to tap the replacement internally threaded item so it will fit the existing external thread?

The actual situation concerns the brass adjuster screw for a Carter plane - I have the threaded rod that screws into the back of the frog of the plane, but no brass adjuster. We know that Carter used all sorts of threads for the studs and the adjuster screws for their planes, so it isn't really possible to do anything except find out what they used for the particular plane and then use the appropriate tap. I have tried all my spare Stanley, Record, Carter, Turner, Falcon Pope, etc adjuster screws and none of them fits the threaded stud! They all seem to be a few thou too small.

In terms of the job, what I propose to do is to cut an external thread on a piece of brass rod or tube to suit one of my spare brass adjusters and Locktite that into the adjuster to fill in the existing thread then drill and tap it to suit the Carter threaded stud. If anyone has another suggestion, I would welcome it.

Cheers

Jeremy

I was right - stupid question.

A quick Giggle and I found this article and this site.

So that should be enough to be going on with....

Any thoughts on the method I proposed?

Jeremy,

I'm finding it hard to understand what you plan to do.

We know that Carter used all sorts of threads for the studs and the adjuster screws for their planes, so it isn't really possible to do anything except find out what they used for the particular plane and then use the appropriate tap.

Do you mean use a tap to make/suit a new adjuster to fit the existing stud ? BTW Are you sure the stud thread is not a left hander?

In terms of the job, what I propose to do is to cut an external thread on a piece of brass rod or tube to suit one of my spare brass adjusters and Locktite that into the adjuster to fill in the existing thread then drill and tap it to suit the Carter threaded stud.

Is this another way of saying you now you are going to ditch the whole Carter stud and make your own stud to suit another adjuster OR are you making a threaded sleeve that internally matches the Carter stud thread and externally matches your adjuster?

Also have you taken into account that most adjusters are left hand thread?

Cheers

Originally Posted by BobL

Jeremy,

I'm finding it hard to understand what you plan to do.


Do you mean use a tap to make/suit a new adjuster to fit the existing stud ? BTW Are you sure the stud thread is not a left hander?


Is this another way of saying you now you are going to ditch the whole Carter stud and make your own stud to suit another adjuster OR are you making a threaded sleeve that internally matches the Carter stud thread and externally matches your adjuster?

Also have you taken into account that most adjusters are left hand thread?

Cheers

Bob

Sorry if I wasn't clear. Yes I am aware that the threads are LH (so I will need to buy special taps and dies).

I propose to keep the existing stud (in part because it is threaded to suit the threaded hole in the back of the frog and making a new one would still involve finding out what the thread is for that...).

What I propose is to re-tap an existing Stanley adjuster to suit the thread of the existing stud. I suspect that I couldn't just drill out the replacement adjuster and re-tap because that would make the hole a clearance for the stud (ie it would be too big to tap). So I was going to get a die to make a threaded brass plug to go in the Stanley (ie usuing a die suitable for Stanley, which I believe is fairly common as far as LH dies are concerned) and then drill it to the right size to cut a thread for the adjuster to fit the existing Carter stud.

Does that make sense, now or is it still as clear as mud?

Cheers

Jeremy

If the Stanley thread is smaller than the Carter, you might get away with running the Carter tap through the existing Stanley thread without drilling/tapping/filling/tapping.

Ummmmmm I find having one of them big fat pocket thread gauges is a really good thing to have.

That way I can work out almost any common kind of pitch (thread turns per unit of measure), and that coupled with a good vernier caliper, gives me an accurate sizing of the thread or what is left of it.

The trick to getting a GOOD thread gauge setup is to get big ones, that have ALL sorts of thread pitches on them...

ISO Fine and Coarse (metric), UNC, UNF, BSW, BSF, BA etc...

And in my combining a number of gauge sets sets onto the ONE RING... I can now gauge the pitch of almost any thread....

http://www.britishfasteners.com/Merc...hreadgauge.jpg

I find it is usually better to actually determine the thread in question first - first and THEN make ones stratagy from there.

Focus Grasshopper, Focus.

That's majik and evil bolt, which has no equal, might have nuts available for 10 to the $1 at the local bolt shop.....

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That way I can work out almost any common kind of pitch (thread turns per unit of measure), and that coupled with a good vernier caliper, gives me an accurate sizing of the thread or what is left of it.

Good luck with old Stanley planes and the like. They rarely used standard anything.

Jeremy, there is every chance you might never find a match for the thread. It's well known that Stanley used proprietary threads on a lot of their stuff, possibly to stop people being able to interchange parts. Not sure if Carter is the same. There are also many different thread types, so it would be trial and error to find a match if it's even possible. You might be better to make a new stud and tap the plane body with a known thread.

Left hand tap and dies are difficult to find, but you can try here: http://www.ejwinter.com.au/tooling.html

I have done some research on this over the last few hours.

As everyone says, Stanley did weird things with the threads. One idea is to use oldfashioned 2 piece dies that are the right tpi but nominally a bit big and push them in tighter to get down to the right diameter.

So, if the Carter doesn't have a standard thread (albeit LH), I will get hold of an old die and thin down the stud to fit and cut the new thread this way.

The idea came from Mark Womack's website which probably explains it better than I can.

Your next challenge is to find a two piece die, in the right thread and left handed to boot! Good luck with it

You're right Silent C - let's see how good Mick Moyles really is.

Actually I was reading a thread in another forum yesterday and the chap there reckoned that by the time he'd purchased the tap and die, it was cheaper to go and 'car boot' another plane of the same type to salvage parts from

But let money not be an object, don't let the damned thing beat you

Originally Posted by silentC

Actually I was reading a thread in another forum yesterday and the chap there reckoned that by the time he'd purchased the tap and die, it was cheaper to go and 'car boot' another plane of the same type to salvage parts from

But let money not be an object, don't let the damned thing beat you

That's what I did the last time when I was trying to get a new adjuster for the Carter C1 rebate plane - I found a really crappy Carter 4 1/2 and the adjuster fitted.

Now I've thought of a new plan for the 4 1/2 which I'm prepare to have a go at because the plane is otherwise rOOted. That looks like being successful, so now I'm back to needing to find a way of putting a Stanley/Record adjuster onto the Carter stud!!!! Ah well....

Originally Posted by jmk89

That's what I did the last time when I was trying to get a new adjuster for the Carter C1 rebate plane - I found a really crappy Carter 4 1/2 and the adjuster fitted.

Now I've thought of a new plan for the 4 1/2 which I'm prepare to have a go at because the plane is otherwise rOOted. That looks like being successful, so now I'm back to needing to find a way of putting a Stanley/Record adjuster onto the Carter stud!!!! Ah well....

Why not take the original stud to a machine shop and get them to turn up a new adjuster nut and machine the require thread in it in a lathe ?

Originally Posted by Woodlee

Why not take the original stud to a machine shop and get them to turn up a new adjuster nut and machine the require thread in it in a lathe ?

Absolutely - but, for me, 90% of the fun is tryig to work out a way to do it for myself.

Besides, I work from 8 am to abot 6 pm monday to friday and very few machine shops seem to be open outside those hours.....

So, the reality is that I have to work out a way to do it in the garage....