Author Topic: A Poor Man's Lathe Dividing Head  (Read 8850 times)

Offline klank

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A Poor Man's Lathe Dividing Head
« on: October 21, 2009, 01:13:15 PM »
Having read Stew's thread on a tool post spindle driven drill, I wonder whether this (very basic) item may also be of interest for dividing from the lathe headstock. Used with such a spindle drill it could prove quite a flexible and useful combination.

I needed some means of simple dividing in the lathe which would be quick and cheap to attain and not require much additional tooling/expence.
 
My next long term project is a large stationary engine, from a kit, which will require several dividing operations in the lathe, and my Sieg C4 is what I need to adapt for this.

There are many old ME articles around on lathe headstock dividing - using the "bull wheel" on the spindle (George Thomas/Myford attachment for one) and more recently (last year?) an article on building a simple one for the Mini Lathe in MEW.

There is no fixed "bull wheel" as such on the Sieg C4, which has turned out to be an advantage.
It seemed possible to use a few of the (supplied) change wheels for simple dividing, if a means could be found to mount them on the end of the headstock spindle.
40, 45 and 50 tooth wheels seemed to be the most useful from those supplied with the lathe.

Thanks to those articles and some new deft input from TransAtlanticDesignAssociates gave me a workable back-of-envelope design.



Here is the "kit" of bits and bobs used.



Everything has been made from (literally) scrap materials and odd off cuts - apart from the main 20mm mild steel mandrel shaft which was one of the few stock items I had on the shelf.

I started with the simple expanding mandrel to fit the 20mm headstock spindle, with a shouldered length on the outboard end of the mandrel to accommodate the internal bore of the change wheel. This is held via a nut/washer against the outboard edge of the gear wheel, the nut pulling up on the length of M8 studding holding in the tapered wedge at the other end of the tapered hollow portion of the mandrel. (Also split 4 ways down its hollowed length). The photo above should make this a bit clearer.
 
The shouldered portion was slotted to hold a small key to fit the chosen gear wheel.

I was fortunate to have scrounged a length of odd-leg aluminium angle bracket from a scrap bin some time ago. A length of this was hacked about a bit to fit around the pulley drive and belt on the Sieg spindle and simply mounted on a small block of steel bolted to the gearbox fire wall in the headstock (again see pics - makes it clearer).

Here is the mounting block for the bracket.




The bracket was carefully marked out for the position of the spindle and bored to a close fit.

Mounted on the block with a 40 tooth wheel on the mandrel it turned out like this.



The dividing peg and block was made from a short length of 1" sq. steel bar, drilled and reamed in part for the "fat end" - 5/16" of the peg and the tail end of the peg at the other  - 5mm.
The peg was made from a short length of 5/16" silver steel, turned down at one end for the "tail".
The dividing end was carefully milled at 30 degrees in the mill, holding the peg in a simple fixture (another little parallel sided block drilled/reamed with a holding grub screw) so that both sides were the same when turned through 180 degrees in the milling vise (swivelled through 30 degrees).

In order to "double up" on dividing from the gears, I decided to make the peg to fit both in-between the gear teeth, AND sit atop each tooth - this meant very carefully slotting the end of the peg wedge end. I eventually got this using a diamond slitting wheel in my mini drill and some careful filing.

Here is the end result - a bit out of focus on macro - sorry.



The block was fitted with a pair of pins and short length of cut-off bolt (M4), using thread lock, to slide in a slot milled in the vertical face of the bracket. This allows flexibility in the positioning of the block, so as to accommodate several gears of varying diameters.
Here's a picture of the finished bracket.



I made a simple brass thumb screw from an old off-cut (hence the strange shape) and a pull-knob for the peg tail (again a bit of scrap hex).
The compression spring for the detent peg is questionable at the moment. I used what was to hand in the odds and sodds box, but must find something better. Maybe then I'll turn up a better pull-knob.

All fitted it looks like this





This is clearly looking a bit crude and certainly not blingy, but it works very well - and cost next to nothing. Time taken - a couple of days I suppose.

I don't think I have seen any thread posted on this site on simple lathe headstock dividing using a peg detent, so maybe this will give someone some ideas.
 
All I have done is adapt and modify previous published designs to make a cheap, simple and very flexible mechanism.
 
Using something like this with Stew's spindle drill, could be a very useful set up for all kinds of drilling/machining operations in the lathe , without disturbing the material held in the chuck or on the faceplate, as well as simple dividing/marking.

Peter

p.s. - I could also fit a "crank-handle" in place of the gear wheel on the end of the mandrel (having removed the block first). The mandrel can be set in the spindle a lot further out to give more clearance.
This might be useful for hand turning/slow-rev thread cutting!

« Last Edit: October 21, 2009, 01:38:21 PM by klank »

Offline sorveltaja

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Re: A Poor Man's Lathe Dividing Head
« Reply #1 on: October 21, 2009, 01:36:59 PM »
Great work klank :thumbup:.

My todo-list has extended again with another project.
 

Offline klank

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Re: A Poor Man's Lathe Dividing Head
« Reply #2 on: October 21, 2009, 01:39:46 PM »
Ha Ha  - a common problem on this site - thanks for the kind comment.

Peter

Offline sbwhart

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Re: A Poor Man's Lathe Dividing Head
« Reply #3 on: October 21, 2009, 06:23:49 PM »
Nice work Peter  :clap:

That indexer with a drill subspindle would be a usfull adition to a workshop   :thumbup:

Thanks for showing

Cheers

 :beer:

Stew
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Offline ozzie46

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Re: A Poor Man's Lathe Dividing Head
« Reply #4 on: October 21, 2009, 07:45:37 PM »


 Thanks Peter, Just in time for me.  :) :) :) :)


  Ron

Offline DeereGuy

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Re: A Poor Man's Lathe Dividing Head
« Reply #5 on: October 21, 2009, 08:55:56 PM »
Hey Peter great job!!!... :bow:

Offline tinkerer

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Re: A Poor Man's Lathe Dividing Head
« Reply #6 on: October 21, 2009, 09:05:03 PM »
Now that is thinking out of the box.  :smart: Way to go. :thumbup: :clap: :nrocks:
Tink

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Online dsquire

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Re: A Poor Man's Lathe Dividing Head
« Reply #7 on: October 21, 2009, 09:47:08 PM »
Peter

Great little add-on project. It will come in handy many times and it was cheap.  :ddb: :ddb: :ddb:

Cheers  :beer:

Don
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Offline klank

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Re: A Poor Man's Lathe Dividing Head
« Reply #8 on: October 21, 2009, 10:54:58 PM »
hi Don, Tink, Bob, Ron, Stew - thanks all for the kind comments - I appreciate your taking the trouble to post.

Best wishes

Peter

Offline geroli

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Re: A Poor Man's Lathe Dividing Head
« Reply #9 on: October 22, 2009, 03:35:04 AM »
Klank that is very clever - Have wished I had a dividing attatchment for the lathe so many times.

I think im going to have to add this one to the tuit list.

Gerhard
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Offline andyf

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Re: A Poor Man's Lathe Dividing Head
« Reply #10 on: October 22, 2009, 04:35:30 AM »
Klank, you've got me thinking  :smart:. With a 60T gear and a worm (mounted at an angle so it would mesh OK) on a shaft carrying a cheap 360o protractor as a dial, a full turn of the worm = 6o on the spindle, and each division on the protractor would represent 1 minute of arc. The hardest bit might be devising some method of locking the spindle, because the detent would have to be disabled when using the dial.

That said, I can't see myself using such a thing. Your method with a 60T gear and a detent would probably cover all my spindle dividing needs. So I'll stop now, before I give myself  :proj:

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline klank

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Re: A Poor Man's Lathe Dividing Head
« Reply #11 on: October 22, 2009, 04:34:43 PM »
Andy, Gerhard - thanks for the kind words.

I cannot think of a way of absolutely locking the spindle solid if using a worm-wheel for "proper", really accurate dividing - this is only a simple indexer - maybe someone will come up with an "improved version"?

Peter

Offline John Hill

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Re: A Poor Man's Lathe Dividing Head
« Reply #12 on: October 22, 2009, 04:42:57 PM »
"Somewhere on the Web..." there is a description of how someone made a worm an wheel (which is not hard, even I can do that! http://madmodder.net/index.php?topic=1773.0).  He fitted the wheel on the back of his chuck and made a removable carrier for the worm which sits on the ways.
From the den of The Artful Bodger

Offline andyf

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Re: A Poor Man's Lathe Dividing Head
« Reply #13 on: October 22, 2009, 05:31:46 PM »
Quote
John Hill wrote:"Somewhere on the Web..." there is a description of how someone made a worm an wheel (which is not hard, even I can do that! http://madmodder.net/index.php?topic=1773.0).  He fitted the wheel on the back of his chuck and made a removable carrier for the worm which sits on the ways.


I've found a design by Ralph Patterson for a version to go on a 7x mini-lathe, which he has stored on Jose Meneses' website: http://www.toolsandmods.com/ralph-patterson.html - about halfway down the page. There are pics towards the end of the PDF.
Looks a bit complicated for the few times I might ever want to use its capabilities, as does the accompanying spreadsheet! Still, it's interesting to look at.

Andy
Sale, Cheshire
I've cut the end off it twice, but it's still too short

Offline JohnDK

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Re: A Poor Man's Lathe Dividing Head
« Reply #14 on: July 13, 2011, 12:06:37 PM »
Many thanks Klank.
I joined today on finding this post.
John North Devon

Offline wheeltapper

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Re: A Poor Man's Lathe Dividing Head
« Reply #15 on: July 13, 2011, 12:21:41 PM »
Hi
neat job.
heres how I did it on the same lathe.

http://madmodder.net/index.php?topic=3302.0

Roy
I used to be confused, now I just don't know.

Offline JohnDK

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Re: A Poor Man's Lathe Dividing Head
« Reply #16 on: July 13, 2011, 03:27:07 PM »
Hello Roy,
This is also very useful!
I've got a smaller Sieg - Clarke CL300M
I reckon I can use your method with a bit of a change as my backplate is a lot more restrictive.
I think I can use the stud and the bolt with a bit of shaving around things.
I love your simple detent with a thumb screw - a great idea.
John

Offline PeterE

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Re: A Poor Man's Lathe Dividing Head
« Reply #17 on: July 13, 2011, 04:05:51 PM »
Nice solution  :clap:

I have made something quite similar for my SIEG C3 from Arc. I will be back tomorrow with pics as the main "body" is getting a lick of paint right now (and is not dry to the touch yet).

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline modeldozer

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Re: A Poor Man's Lathe Dividing Head
« Reply #18 on: July 13, 2011, 05:37:24 PM »
Hi all,

For those interesed there are plans published for a simmilar setup in the Workshop practice series from Special interest model books, N0.43 The mini-lathe.  It is on my to do list once my lathe is running again.

Abraham

Offline krv3000

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Re: A Poor Man's Lathe Dividing Head
« Reply #19 on: July 13, 2011, 07:55:06 PM »
well i will have to av one of them  :)

Offline PeterE

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Re: A Poor Man's Lathe Dividing Head
« Reply #20 on: July 14, 2011, 06:42:00 AM »
Hi again, the paint is now dry so this is my version of the simple headstock dividing head.

All the different bits ...


...and when assembled it looks like this:


BR

/Peter

(More details in an own thread in the projects group.)
Always at the edge of my abilities, too often beyond ;-)

Offline wheeltapper

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Re: A Poor Man's Lathe Dividing Head
« Reply #21 on: July 14, 2011, 07:10:15 AM »
Very nice. :nrocks: :nrocks:

Roy
I used to be confused, now I just don't know.

Offline PeterE

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Re: A Poor Man's Lathe Dividing Head
« Reply #22 on: July 14, 2011, 09:04:16 AM »
Thanks a lot wheeltapper.

BR

/Peter
Always at the edge of my abilities, too often beyond ;-)

Offline JohnDK

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Re: A Poor Man's Lathe Dividing Head
« Reply #23 on: July 14, 2011, 03:30:44 PM »
Peter/
After looking at your own Project Thread, you've succeeded in making me rethink whether the easy solution is the best!!
Your pictures are superb and explain exactly how the thing works and the advantages you have built in.
I am now reconsidering the best way to go forward!!!!
Many thanks,
A very thoughtful,
John