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View Full Version : Make A Lead Screw By Hand?



MachineMan384
02-23-2015, 04:44 PM
Hello, new member here. I am just getting into metalworking trades as a hobby and preparing to undergo training to become a machinist at community college. I have a great interest in the history of technology and as such, the history of industry. I have David Gingery's ""Build Your Own Metalworking Shop From Scrap" and am acquiring books as I can on patternmaking and so forth. I hope to at some point in the future build the Gingery machine shop.

One thing I was reading though was about how a critical innovation in allowing the Industrial Revolution to really ramp up was the invention by Henry Maudslay of the screw-cutting lathe. I read that the principle innovations were the slide-rest, lead screw, and set of change gears and how Maudslay combined them together. The thing is, before inventing the screw-cutting lathe, Maudslay had to make his lead screw by hand.

Well as a project, I would like to someday make a version of the Maudslay lathe from scratch, including hand-cutting the lead screw. What am I wondering is how would I go about learning how to do this? Are there any books or anything? I have Googled the subject on how to make a lead screw but it's always using machine tools to do so, not by hand (because who in their right mind in modern times would want to cut screws by hand?:) ).

Any suggestions appreciated.

loose nut
02-23-2015, 05:11 PM
I read somewhere and I don't remember where, that he laid out a short section, a few inches, then chiseled it out and filed to finish. He then used this to cut other sections (using a follower on the short section) until he had a long leadscrew. After that he used that leadscrew to cut other better leadscrew's and repeat and repeat until he had one that he considered good enough. It is important to remember that in those days machining generally meant hammer and chisel, some kind of metal cutting hand saw and files so they got pretty good at doing those things. Lost skills for most today. Taps and dies didn't exist then, threads where either filed to shape or hand chased on some kind of rudimentary lathe IE: pole or treadle lathes.

Good times.

bob308
02-23-2015, 06:09 PM
in one of the machinist bed side reader books. he tells of a guy cutting threads on a lathe that had no lead screw.

oldtiffie
02-23-2015, 06:30 PM
Theoretically at least - and probably realistically too - given that "feed rates" are just a set progression of the saddle per turn of the head-stock spindle that if the right gear-train could be set that a lead-screw or any thread could be cut if the lead of the "feed" (via the rack on the lathe itself and the pinion on the saddle) all that would then be needed would be to engage the longitudinal feed.

You would have to keep it engaged throughout and just reverse the lathe to start again - no threading dial either - just as you would (have to) if cutting metric threads on an imperial/inch lead-screw or even if cutting metric thread on a metric lathe.

So, if that worked then a lead-screw could be cut on a lathe without using the lathe lead-screw.

"Feed rate" cutting is really just a variation of lead-screw thread-cutting after all.

mklotz
02-23-2015, 06:32 PM
A guide for making the first pass at at leadscrew can be made by winding heavy wire on a cylinder and arranging a follower to track the valley between the adjacent wire turns.

Richard King
02-23-2015, 06:42 PM
Go to Amazon and but this book. I am a Journeyman and reference it all the time. " Shop-Theory-Henry-Trade-School Book " plus follow and learn from Tom on You Tube, he is GREAT machinist. Rich https://www.youtube.com/user/Figbash3

Gary Paine
02-23-2015, 06:51 PM
By the time Maudslay was building his first screw cutting lathes, woodworkers had long ago adopted the wooden screw into clamps and vices. They were cutting threads with screwboxes. Blacksmiths too had thread cutting dies, but they couldn't cut a long straight on a bar. Roy Underhill shows a technique for making the big wooden nuts. He laid a spiral wrap of paper around the cylinder and sawed a kerf along the spiral. A piece of metal in the kerf caused the "screw" to move forward. The end of what I just called a screw was inlet with an adjustable cutter that cut the big threads in the matching nut as it wound thru.

kendall
02-23-2015, 07:22 PM
A guide for making the first pass at at leadscrew can be made by winding heavy wire on a cylinder and arranging a follower to track the valley between the adjacent wire turns.

Two strips of suitable width wound together over a bar, then remove one strip. (Or prebend one as as a follower) I could see doing it with solder on the remaining one and winding them hot.

boslab
02-23-2015, 07:26 PM
According to what I have read the original lead screws were cut by hand with a chaser, looks like a piece of a screw machine die head, it has a thread, with the helix angle, the technique required to hand chase does require practice, the thread was "struck" into the rotating bar with the heel of the chaser, steady pressure on the chaser cases it to pull itself along, I have tried it and it does work quite well, apparently maudslay used this technique.
Mark

MachineMan384
02-23-2015, 07:49 PM
Thanks for the information thus far.


in one of the machinist bed side reader books. he tells of a guy cutting threads on a lathe that had no lead screw.

I'd love to get those books, problem is they each cost an arm and a leg right now. From what I had read, the author went through a nasty divorce and his ex-wife is entitled to profits from the books or something and thus he stopped printing them.

oldtiffie
02-23-2015, 07:52 PM
http://en.wikipedia.org/wiki/Henry_Maudslay

http://en.wikipedia.org/wiki/Screw-cutting_lathe

https://www.google.com.au/?gws_rd=ssl#q=maudsley+lead+screw

MachineMan384
02-23-2015, 07:56 PM
Go to Amazon and but this book. I am a Journeyman and reference it all the time. " Shop-Theory-Henry-Trade-School Book " plus follow and learn from Tom on You Tube, he is GREAT machinist. Rich https://www.youtube.com/user/Figbash3

Thanks for the suggestion, looks like a very cool book and Youtube source :)

vpt
02-23-2015, 08:28 PM
If you already have the lathe but need a leadscrew for it to cut threads I would think it would be a very easy task to "free hand" a decent length of threads eventually that could be copied over and over again into a long screw like mentioned good enough to cut a better screw and so on and so forth.

oldtiffie
02-23-2015, 10:09 PM
That "copying over and over" rather suggests a pretty good (almost) "metrology" set-up as the measuring set-up would need to be very good indeed.

It may be easier if a horizontal universal mill and universal dividing head were used - with a good vertical milling attachment.

http://www.lathes.co.uk/victoria/img9.gif

http://www.lathes.co.uk/victoria/

Don Young
02-23-2015, 10:57 PM
It should be possible to cut a decent screw on a lathe using sprockets and a chain to move the carriage at a uniform rate proportional to the spindle rotation. I have seen pictures of some machines using chain drive on a carriage.

yf
02-23-2015, 11:25 PM
the reason why a screw thread is called a thread, it's because the way blacksmith did it in the past, was to wrap a thread around a rod and file adjacent to the thread.
another way of producing a screw would be to take 2 equal size square bars and wrap them around a round rod.The two square bars would then be unscrewed one of them would be brazed onto the round rod and would form the screw. The other twisted square bar would be brazed into a hole in the body of the vice or the machine part to become the nut.

Paul Alciatore
02-23-2015, 11:25 PM
Can you say "public library"? Or "university library"? I would bet that places like MIT would have excellent books on the history of technology. You may not be able to check the books out if you are not a student, but I doubt that any library would stop you from looking at them. I have just walked into university libraries and read to my heart's content.

Even small towns have public libraries. And most, if not all of them can request books not in the local collection. It may take a few days, but you can probably get any book in the state system.

As for making a screw from scratch, I would do it with wire wound tightly on a cylinder. If the wire is drawn through a die, it will be fairly uniform in diameter. Wire making technology has been around for a long time.

One reference (there are many): http://larsdatter.com/wire.htm

That will give you a good start and the "wire screw" can be any length that you can make the wire for.

From there, you use averaging techniques to make successive generations of screws that are progressively more consistent than the previous generation. Make two wire screws and mount them side by side. Make a follower that rides on both of them and across many threads so both the individual thread errors and any errors in each individual wire screw are averaged out to a great extent. Make two more screws and use them to make a third generation screw. Reverse one of them when mounting them so long period errors will be better averaged out.

You continue with more generations and using additional averaging techniques until you reach the consistency that you want.

This will produce a screw with a random pitch. Gearing can be used, just as we do today on our lathes, to make one with the pitch we desire.

This will take a lot of work. And a lot of thinking.


Thanks for the information thus far.



I'd love to get those books, problem is they each cost an arm and a leg right now. From what I had read, the author went through a nasty divorce and his ex-wife is entitled to profits from the books or something and thus he stopped printing them.

SGW
02-23-2015, 11:43 PM
This is a good book about the history of machine tools: http://books.google.com/books/about/English_and_American_tool_builders.html?id=X-EJAAAAIAAJ

As far as making a leadscrew, I think most of the ways of doing it have been described. Once you get an approximate leadscrew, you can cast a long nut around it, and by virtue of its length it will tend to average out the thread pitch variation. Then you use that to make a better one. Obviously, it's not quite that simple, but that's the essence.

MachineMan384
02-24-2015, 02:56 AM
Paul and SGW, thanks for the links. Also again thanks to everyone else for the information thus far. One problem for me at the moment is all of these lead screw making methods you have all described sound like Greek to me. I guess I have to learn machining terminology to understand what it all means. But basically the gist seems to be to make one lead screw, then make multiple others based off of the original and then each other to refine them more and more?

Euph0ny
02-24-2015, 06:51 AM
...all of these lead screw making methods you have all described sound like Greek to me. I guess I have to learn machining terminology to understand what it all means...

Don't worry. The idea is quite simple, even if the vocabulary for describing it is new to you. Some "easy" method is used to create a helix (corkscrew) shape, which can then be reproduced in metal, creating a portion of threaded rod. Iterative and averaging procedures are applied which increase the precision of the spiral with each new generation created.

To get up to speed on the machining vocabulary for threads and threading, have a look at Tubalcain's / MrPete222's machine shop tips videos (https://www.youtube.com/user/mrpete222/videos?sort=da&view=0&flow=grid), starting at Nos 1-10, then 17 & 18, (all about 4 years old) then do a search on his channel for "threading". Great stuff...

J Tiers
02-24-2015, 08:31 AM
If you cut one by hand, it will be extremely variable in pitch (at least for "real" purposes).

So you make a matching female thread in a long section, and run it back and forth with lapping compound, lapping them together. eventually you get an average thread of "some" arbitrary pitch. But it will be as accurately even as your lapping job made it.

Lapping assumes your initial cut thread is not too bad....

By measuring that pitch, you can determine what gearing is required to cut a pitch that you DO want. You can repeat the lapping process on the new thread to get an even better thread, which again you must measure the pitch of, and gear to develop an even more accurate pitch to be cut.

That can be developed to any degree wanted, and is somewhat similar to lapping 3 stones to get a flat surface plate, except that with only one dimension at stake, you don't need 3 pieces..

Baz
02-24-2015, 02:38 PM
I'm not sure about the lapping as above but the follower nut for the second generation mus tnot be a long one or it just 'rides the peaks'. I read somewhere how two or more short nuts are used and linked by levers to produce the average.

Paul Alciatore
02-24-2015, 03:20 PM
I think an important point here is that it is not just:

the technique for producing the first screw,

the long nut,

the lapping,

the multiple generations of screws,

using two screws with one reversed in direction,

or any other individual technique.

It is a combination of all or many of the above AND they must be combined in a proper and well thought out sequence to insure that the errors will be reduced and not increased. You must consider all forms of errors that each process can reduce and which ones it will not reduce and may even increase.

And, if you are making the first lead screw, you will not have any independent way of checking your results. This is not a job for a novice.

J Tiers
02-24-2015, 08:59 PM
That's true, bad technique = bad result.

The idea is to make a leadscrew first which which may be of any actual pitch but is very accurately that SAME pitch everywhere. By appropriate gearing that very accurate pitch screw can be used to make an accurate SPECIFIC pitch.

As for the long nut vs 2 short ones, it may differ as to whether you are averaging the pitch on a single reference screw, OR if you are trying to lap a screw to even out the pitch. Two nuts at a distance is effectively a long one, but has less area in contact.

When trying to even out the pitch, touching on peaks is likely what you want, as they will be worn down first.... much like scraping a surface to make it flat, you are trying to "flatten a helix" to make a PERFECT helix without bumps.

MachineMan384
02-24-2015, 10:08 PM
And, if you are making the first lead screw, you will not have any independent way of checking your results. This is not a job for a novice.

Yes, making a lead screw from scratch isn't something I would attempt as a starter project, I just nonetheless would like to do it someday in the future when I have some skills built up.

J Tiers
02-25-2015, 08:36 AM
And, if you are making the first lead screw, you will not have any independent way of checking your results. This is not a job for a novice.

Actually, you WILL have such a way..

You can measure the pitch with micrometer, gage blocks, etc. Directly over the threads, or by measuring the advance of a nut, which is the usual way.

You can measure the various diameters the same way, OD (major diameter), minor diameter, pitch diameter. Angle of the threads etc can also be measured.

It's a physical object, and so can be accurately measured like any other object. Unless of course, you are suggesting that the task is to re-create the first micrometer with no other similar tools available.

camdigger
02-25-2015, 12:26 PM
The easiest way would be to use a multi point "chaser" on what is essentially a wood workers tool rest. I can only imagine how much practice it would take, but multiple passes should give a similar class of thread as rolled threaded rod.

The some kind of wire wrap or similar feed nut or even a nut of soft, easily cut material like brass or aluminum tapped using a short segment of the threaded rod.

The Gingery machine tools used common hardware store threaded rod for all feed and lead screws.

My 0.02TL

oldtiffie
02-25-2015, 06:43 PM
This thread pretty well infers that both the matching lead-screw and nut will both be made from a "billet".

https://www.google.com.au/?gws_rd=ssl#q=making+a+lathe+lead-screw

It pretty well comes under the heading of "self flagellation" ("scraping" too) for me so I would not even consider starting.

http://en.wikipedia.org/wiki/Self-flagellation

https://www.google.com.au/?gws_rd=ssl#q=self+flagellation

MachineMan384
02-25-2015, 08:04 PM
The Gingery machine tools used common hardware store threaded rod for all feed and lead screws.

My 0.02TL

So the Gingery machine tools require some things from the hardware store or can they be completely manufactured from scratch? I was under the impression that the Gingery machine tools essentially could be made form just a pile of raw metal and wood...? I suppose though one could make their own feed and lead screws if willing to take the time.

Ironwoodsmith
02-25-2015, 08:49 PM
I can envision a set of pinch rollers geared to the lathe spindle and draw-feeding the carriage in a linear fashion using a flat bar or solid rod to accurately cut the feedscrew. It should produce a very accurate thread pitch with an existing lathe.What do you think?

oldtiffie
02-25-2015, 09:03 PM
Hello, new member here. I am just getting into metalworking trades as a hobby and preparing to undergo training to become a machinist at community college. I have a great interest in the history of technology and as such, the history of industry. I have David Gingery's ""Build Your Own Metalworking Shop From Scrap" and am acquiring books as I can on patternmaking and so forth. I hope to at some point in the future build the Gingery machine shop.

One thing I was reading though was about how a critical innovation in allowing the Industrial Revolution to really ramp up was the invention by Henry Maudslay of the screw-cutting lathe. I read that the principle innovations were the slide-rest, lead screw, and set of change gears and how Maudslay combined them together. The thing is, before inventing the screw-cutting lathe, Maudslay had to make his lead screw by hand.

Well as a project, I would like to someday make a version of the Maudslay lathe from scratch, including hand-cutting the lead screw. What am I wondering is how would I go about learning how to do this? Are there any books or anything? I have Googled the subject on how to make a lead screw but it's always using machine tools to do so, not by hand (because who in their right mind in modern times would want to cut screws by hand?:) ).

Any suggestions appreciated.

If you are going to do/make the whole lather there are more than one lwead-screw and nut combinations involved:

- main lead-screw and half nuts;

- cross-slide and top-slide/s and nut/s and;

- tail-stock quill screw and nut.

J Tiers
02-26-2015, 12:15 AM
If you are going to do/make the whole lather there are more than one lwead-screw and nut combinations involved:

- main lead-screw and half nuts;

- cross-slide and top-slide/s and nut/s and;

- tail-stock quill screw and nut.

Of those, only the leadscrew really has to be a high precision part. The others clearly would not suffer if they were also high precision, but in their case, it is fairly easy to deal with parts that are just reasonably good. You can measure and adjust to get the desired result.

Once you had the leadscrew, making the other screws would be nearly as easy as it is on any lathe. You might have a bit of trouble with the first one and adjusting the depth of cut.

oldtiffie
02-26-2015, 02:24 AM
Why not heat and roll your lead-screw/s?

https://www.google.com.au/?gws_rd=ssl#q=lead+screws+and+anti-backlash+nuts&revid=199083304

https://www.google.com.au/?gws_rd=ssl#q=manufacturing+of+lead+screws

oldtiffie
02-26-2015, 02:36 AM
Why not use a square section wrought or other steel rod the diagonals of which are just a smaller than a straight round pipe/tube?

Put the square section in the round tube.

Fix one end of the round tube and square section (separately) and put a (largish)"tap wrench" or similar on the other (free) end of the square section.

Heat the round rod and the square section until the square is red to white hot.

Twist the pipe.

Do this progressively along the pipe and square section.

You may be surprised at how accurate the helix on the square section will/can be even if a bit "coarse" - practice may be needed - but it can be the start of a reasonable lead-screw.

Its quite common in the manufacture of ornamental wrought iron.

"Evan" (Williams) made an excellent machine for this - I'd appreciate if anyone who has a link to Evan's machine could post a link to the thread showing how it was done.

This is basic forge/Blacksmith stuff.

camdigger
02-26-2015, 04:40 AM
So the Gingery machine tools require some things from the hardware store or can they be completely manufactured from scratch? I was under the impression that the Gingery machine tools essentially could be made form just a pile of raw metal and wood...? I suppose though one could make their own feed and lead screws if willing to take the time.
The "from scratch" part comes from the castings being made from patterns built from readily available materials. The author was not trying to eliminate all commercial products for the sake of doing it all from barstock and scrap, but rather generating machine tools from materials economically and readily available from a local hardware store anywhere.

Dave Gingery used threaded rod, taps, drills, screws, CRS, and barstock that would be available from any Lowes or the like (with the possible exception of dimensional CRS).

What he did do from scratch was made his own foundry set-up, made his own patterns, flasks, and castings and illustrated the means to create the machine tools using only hand tools i.e. only hand methods - no machines or machine tools other than a hand held drill.

peekaboobus
02-26-2015, 04:59 AM
I've done that. Got an extrusion. Clamped it on a vise. One of those with the bottom exposed. Extended out the extrusion only a tiny amount to increase stiffness. Then threw in the die to start forming the threads. As you progress, you release the clamp on the vise and extend just a bit more uncut material. You keep doing it until you are finished.

Ive also done it on a lathe chuck. Same idea. Extend a bit, thread it. Extend more, thread it. Until you are done.

MachineMan384
02-26-2015, 07:44 PM
The "from scratch" part comes from the castings being made from patterns built from readily available materials. The author was not trying to eliminate all commercial products for the sake of doing it all from barstock and scrap, but rather generating machine tools from materials economically and readily available from a local hardware store anywhere.

Dave Gingery used threaded rod, taps, drills, screws, CRS, and barstock that would be available from any Lowes or the like (with the possible exception of dimensional CRS).

What he did do from scratch was made his own foundry set-up, made his own patterns, flasks, and castings and illustrated the means to create the machine tools using only hand tools i.e. only hand methods - no machines or machine tools other than a hand held drill.

I see. What is CRS?

oldtiffie
02-26-2015, 07:59 PM
CRS = cold rolled steel

koda2
02-27-2015, 12:18 AM
CRS = cold rolled steel

No its a condition that affects old machinists who have smelled too much cutting oil burning.
CRS = can't remember s**t:)

vpt
02-27-2015, 07:58 AM
I am surprised no one mentioned ordering a acme thread rod from McMaster by hand.