Threading a long rod and keeping it straight.

[terryd]

Hi GOG ,

UK Midlands, Probably due South of you

Terry

 

[BaronJ]

Hi Terry,

Hi GOG ,

UK Midlands, Probably due South of you

Terry

Thank you.
The reason I asked was that it occurred to me that you might have been the guy that I made those long threaded rods for. Its been a long time.

I'm near York. The guy I remember was called Terry, he lived in Lichfield.

 

[Ken Brunskill]

Interesting discussion, lot of ways to "skin the cat" are'nt there? So I served a Tool & Die Apprenticeship 1961-1965, as was the custom back then, we were allowed/encouraged to make our own tools, the attached photos show the 'Die Holder' and a 1/2" dia. drill blank, this is very similar to terryd's unit. Having read all the posts, it reminded me of using my 'Die Holder' with the die toward the headstock, once the thread has become as long as can be supported by the Drill Blank, acorrectly sized (for the major dia. of the thread being created) is placed in the opposite end. Worked fine for threads up to 9" in length, don't see why it would not work for longer rods.
As shown the 'Die Holder' has two (2) bore sizes for the popular split die sizes.

Good luck, stay well all.

 

[terryd]

Hi Ken,

Great minds thinking alike

TerryD

 

[Longboy]

How do people do this? I'm currently using a die in a holder, held in my hand -- if I made up a die holder to be held in a chuck in my tailstock would it work?

Reverse procedure. Put your Jacobs in the tail stock. Your brass rod in the chuck and the die in the 3 jaw chuck in head stock. Automatically squared up, stock to die. Power up after releaseing the tail stock from the ways. At least, this works well for smaller mini lathes.

 

[Ken Brunskill]

Longboy, I like that idea for 1/4" (6mm) diameters and above for small lathes with light tail stocks. Depending on the the material being threaded and desired thread quality results, that approach could result in loose fitting threads as it is putting quite a axial load-bias on the thread cutting die. Suspect that a larger lathe (13" +) certainly would in my opinion/experience. Of course we are not making mil. spec. parts here are we?

All in all, this thread has shed a lot of light on a seldom discussed topic.

 

[Longboy]

That was my best guess.....larger machines make these small dia. rounds & rods look frail. Brass rod can get the twisty in threading. Shouldn't have any axial load as the die drawing on the brass rod pulls the tail stock forward but may depend on the weight and drag of your machine tool size. You haven't much length of thread to do and Loctite cures underclass threading......let us know how you proceeded.

 

[Ken Brunskill]

Must be some kind of serendipity as I just came back from the shop a few minutes ago, I am in the end stages of building an model Atkinson Differential (See thread (Another Atkinson Differential), any way one of the very last pieces to fabricate was the 'Needle' for the carburetor. I did not have a traditional #2-56 split die, so I had to revert to the dies may father gave me. I am so fortunate to have had a fantastic dad, who was a Maintenance Machinist for Friden Calculator Co, he was their ace on repairing their Automatic Screw Machines. The tool seen in the photo was something he made to hold the Automatic Screw Machine Dies, he designed and built it with a precision .375" hole in the back that as the photo shows keeps it centered similar to the device I made in my apprentice ship.

The thread cut in the photos is a #2-56 X 5/8" (.625") and the turned out well, not as straight as the Aluminum tool which has a longer guide component to it, (Shaft - Hole in Die Holder) than this tool does, as can be seen. I measured the wobble after threading and it was .007" TIR.

 

[terryd]

Reverse procedure. Put your Jacobs in the tail stock. Your brass rod in the chuck and the die in the 3 jaw chuck in head stock. Automatically squared up, stock to die. Power up after releaseing the tail stock from the ways. At least, this works well for smaller mini lathes.

Hi Longboy,
That's a good idea as long as you have solid dies, which are mostly used for 'chasing' here in the UK. Here, for threading the dies are invariably split dies which of course are adjustable so that threads can be adjusted to fit specific parts. These would have to be held quite tightly in the chuck to prevent them from being pulled out by the drag of the tailstock = this would cause undersized threads surely? With the tailstock die holder the die is held in place by the three grub screws which are also used for adjustment.

TerryD

 

[justisla]

Put a shim in the split?

 

[BaronJ]

Hi Guys,

?? Why put a shim in the gap of a split die ? A correctly made die holder will have three pointed screws in it. Two to hold the die and one to prevent the gap from closing up too far.

The two screws holding the die are used to close the die to size as well as hold it, the third screw besides holding the die prevents the die closing up any further than what ever you have set.

American style dies with the internal adjusting screw use all three holder screws to secure the die.

 

[goldstar31]

I agree with John B. What on earth will improve. what is probably a gimcrack solution anyway.

I was writing a hopefully nice letter. to one of our younger btretheren who was making steadies for sale.

Ye Gods wgat's next?

Well, I have got a pair of steadies for my sold Myford ML10 for sale. Well then I suggested that he consider Martin Cleeve's solution in those forgotten days.
He was a bit like an even older writer who sketched a steady made out of--- wood. He is the long gone geyser that everybody is copying- or nearly every one copies.
So I looked at my Super7B one and then the unused one on the Chinese C4. The bearing fingers bearing surfaces are tiny and virtually useless.
Cleeve, who not only wrote but MADE special screws, made something solid in metal and added correct collars of and inch and a half and called it ' his fixed bushing steady'.
I his almost forgotten write ups he held an 11 foot standard of steel in in his lathe- which poked out into his garden through a hole.
You think about it, held accurately in an independent chuck on 'waving about' in the garden.

Clever?

 

[justisla]

Baron J
Perhaps i should have included the quotes. I seem to have problems getting them to come out in the post.
The suggestion made earlier was to put the die in the 3 jaw chuck & the rod in the jacobs chuck such that the rod passed through the headstock. The follow up to that was that the 3 jaws would compress the die too much & may produce a thread that was too loose. I just made the suggestion that to prevent a split die from closing too much in such a set up one might perhaps shim the split. I have no idea if that would solve the issue, so i put a question mark after the remark.
Apologies if I mislead anyone. Perhaps my inexperience at such activities should have precluded me from commenting in the first place. However, if I do come upon the problem sometime in the future I may well try it.

 

[BaronJ]

Baron J
Perhaps i should have included the quotes. I seem to have problems getting them to come out in the post.
The suggestion made earlier was to put the die in the 3 jaw chuck & the rod in the jacobs chuck such that the rod passed through the headstock. The follow up to that was that the 3 jaws would compress the die too much & may produce a thread that was too loose. I just made the suggestion that to prevent a split die from closing too much in such a set up one might perhaps shim the split. I have no idea if that would solve the issue, so i put a question mark after the remark.
Apologies if I mislead anyone. Perhaps my inexperience at such activities should have precluded me from commenting in the first place. However, if I do come upon the problem sometime in the future I may well try it.

Ah I see, no problem. Its a bad idea anyway to put a bare die directly in the lathe chuck. You should use a proper die holder. Also pulling the tailstock along on those thin threads won't do the threads any good, it will cause them to stretch.

 

[justisla]

Ah I see, no problem. Its a bad idea anyway to put a bare die directly in the lathe chuck. You should use a proper die holder. Also pulling the tailstock along on those thin threads won't do the threads any good, it will cause them to stretch.

Would it not be simple to apply pressure to the tailstock with one's hand?

 

[Longboy]

Would it not be simple to apply pressure to the tailstock with one's hand?

That is the right answer! Laying the book down and doing the set task with the tooling one has available most likely will get you there. Easy set up to try. No need to make or purchase specialize holders. Will not be a time / cost consideration if results are not satisfactory for this part. You certainly can get around stretching threads helping the tail stock along as the rod moves thru the die.
As for torque twisting the brass rod for a 5-44 threads.......then the split die gets around that. Also it is unlikely that the "Committee for the Proper Use & Procedures of Machine Tools" will come to your shop and issue citations for going rogue. ( just in case you were wondering!)
But I still can't imagine doing 5-44 single point.....not even on a mini lathe!

 

[terryd]

The problem with shimming the die is how thick should the shim be? The obvious answer, as thick as the slot! However at 'full stretch' i.e. die at the max opening, it will give an oversize thread, I always have to compress the die a little using the adjusting screws of the holder to tune the thread once the initial cut has been made.

As I said in a much earlier post the tailstock die holder I made, not my design - I just tweaked it a little - can cope with threads up to 3/8" dia x 12" long. The length of screwed rod which iI can make is because of the length of the hollow die holder itself. The support bar and its morse taper are turned from one bar and drilled through 10mm with a long jobbers twist drill I bought for the job. If I need longer than 12" I buy a metre of threaded rod.

It took an evening to make and has saved me an immeasurable amount of time and has given accurate results every time. The actual die holders are interchangeable with one grub screw to loosen and I keep each of my most used sizes in their own holder only changing one when I need an unusual thread.

I wouldn't be without it.

Stay safe

TerryD

 

[justisla]

Surely one can use a relatively "soft" shim & if the thread is tight one can just tighten the chuck jaws in a similar way to adjusting the screws on a die holder. Is that any harder in the grand scheme of things?

 

[terryd]

That is the right answer! Laying the book down and doing the set task with the tooling one has available most likely will get you there. Easy set up to try. No need to make or purchase specialize holders. Will not be a time / cost consideration if results are not satisfactory for this part. You certainly can get around stretching threads helping the tail stock along as the rod moves thru the die.
As for torque twisting the brass rod for a 5-44 threads.......then the split die gets around that. Also it is unlikely that the "Committee for the Proper Use & Procedures of Machine Tools" will come to your shop and issue citations for going rogue. ( just in case you were wondering!)
But I still can't imagine doing 5-44 single point.....not even on a mini lathe!

Good job the engineers in the past didn't take the attitude " doing the set task with the tooling one has available most likely will get you there", if they had we would still be making stuff with hand tools which in turn had to be hand made such as files made with chisels and charcoal case hardening as they would be happy making stuff with the "available tooling".

Personally I'm really glad that people like Henry Maudsley, Brunel, Whitworth and James Watt et. al. were inquisitive, adventurous and ambitious enough to push the envelope and develop new tools and methods - and spend the time and effort to make them. Still as the Beatles said:

He's as blind as he can be
Just sees what he wants to see

TerryD

 

[justisla]

Good job the engineers in the past didn't take the attitude " doing the set task with the tooling one has available most likely will get you there", if they had we would still be making stuff with hand tools which in turn had to be hand made such as files made with chisels and charcoal case hardening as they would be happy making stuff with the "available tooling".

Personally I'm really glad that people like Henry Maudsley, Brunel, Whitworth and James Watt et. al. were inquisitive, adventurous and ambitious enough to push the envelope and develop new tools and methods - and spend the time and effort to make them. Still as the Beatles said:

He's as blind as he can be
Just sees what he wants to see

TerryD

With due respect you have just contradicted yourself. Longbow suggested an alternative idea. -- He suggested a different method-he pushed the envelope. & you are saying he should not. Is one "blind" not to accept that? Nobody has actually said WHY one cannot put the die in the chuck with soft shims. Then push the tailstock along. I do not know why not, but I am certainly not going to accept, " well because it is not the done thing" as an answer. Furthermore, if one has only a single item to make can one tell me why one would want to waste time on an uneccessary task constructing a tool - other than the interest in making something. If that is what you like doing then there is nothing wrong with that, It is a hobby for most people anyway. I sometimes make things to solve a problem that never exists. But, hey, I was having fun !!!
Henry Maudsley, Brunel, Whitworth and James Watt Were on a different path for a different reason. So I do not accept those as relevant examples.