View Full Version : Poor Man's R/T

12-14-2003, 02:32 AM
Here's the degree wheel I recently made for the spindle on my Jet 10x24 lathe:

It has already proven useful for easily and accurately marking parts. The part is chucked and some reference feature is positioned with a dial indicator. The vernier can be moved by loosening the Breeze clamp which holds it to the headstock. The part can then be rotated to the desired angle.

In order to use the "rotary table" for more than marking parts, I need some way to lock the spindle solidly without moving it in the process. Obviously, the back gear won't do it since it moves the spindle as it engages, and it allows too much movement.

I'd appreciate any suggestions on how I can do this.

Oh, the green plastic piece covers the band saw blade, which you can see next to the 140* mark. There are 360 teeth on the length of 14tpi blade.


[This message has been edited by winchman (edited 12-14-2003).]

12-14-2003, 02:36 AM
I'm working on a similar project right now Roger. I'll show what I have when it's finished.

John Stevenson
12-14-2003, 06:32 AM
That's a really nice piece of work.
I did some years ago for a Dore Westbury mill and I know the amount of effoert and concentration needed not to make mistakes.

For locking your spindle how about using an expanding mandrel on the outboard end that carries a disk with slotted arcs cut in it and bolt this to a fixed point on your machine.
It depends on machine design and if you need to use long bars with this setup.

I did a similar index dial a while ago for my slotter. This had the smallest dials I have ever seen for a machine of it's size.
The match BTY is a large one http://bbs.homeshopmachinist.net//biggrin.gif
As I didn't have a lot of time I found a piece of steel to make a new dial out of and bored it to fit. I then took a cleaning pass on the OD and measured it.
Taking the OD and multiplying by Pi then drew a line out this long on the CAD system, my CAD system, Fastcad, has a divide command so telling it divvide by 200 it imediat;y drew 200 equal lines on the Pi base line.
A bit of trimming to get the 10's and 5's the right hight and I printed one out and wrapped t round the dial.
For some reason, paper thickness, printer etc this wsn't quite right so I went back and scaled the drawing slightly, reprint and Bob's your uncle.
Secured wth a bad of glue and a wrap round with sellotape to protect it and I now had a nice big dial for not a lot of work.
Bear in mind this is now over 5 years old on a machine that does quite a bit of work.
It could do with replacing if I can remember where I put the rest of the printed sheet http://bbs.homeshopmachinist.net//biggrin.gif

John S.

12-14-2003, 08:44 AM
John, Roger,

That's exactly what I am making today, an expanding mandrel for the left end of the spindle. A really precise one. It will be able to hold change gears for dividing, a disc brake for locking the spindle and a spindle handle for hand turning. I'm still wondering if I should case harden the mandrel plug (1018 steel, annealed) or just leave it soft. Suggestions? The taper in the mandrel and the plug is cut at 10 degrees so it won't self lock. I still have to figure out a setup for my milling attachment so I can slit the mandrel 3 ways.

12-14-2003, 09:07 AM
The CAD-generated paper strip is a good idea. You can see the well worn example on my three-jaw chuck:

I had a pointer with a magnetic base which I could attach to the headstock when needed.

The larger wheel and paper strip sure made a vast improvement on your handwheel.

I like the suggestion on the expanding mandrel. I rarely do long bars, but I often use threaded rod through the spindle to provide extra support to pieces in the chuck. I can make an expanding mandrel with a hole large enough for a threaded rod.

Slitting the mandrel doesn't have to be perfect for this purpose, since concentricity isn't critical.

I could make an arm to clamp on the mandrel. A turnbuckle attached to the other end of the arm could run down to the lathe stand. After getting the spindle in the approximate position, clamp the arm tight on the mandrel, and do the final adjustment with the turnbuckle. The arm would be removed from the mandrel for normal lathe operations, but the mandrel could stay in place.

Sounds like a plan. Thanks for the suggestion.


12-14-2003, 11:59 AM
Evan, my buddy down the road has the Versa-mill attachment that does just that,they used but soft 12L14 for the expander,so I wouldn't worry about cold rolled.

12-14-2003, 03:31 PM
Already slit the mandrel, worked like a charm in my milling attachment. Pictures at eleven.

[This message has been edited by Evan (edited 12-14-2003).]

John Stevenson
12-14-2003, 03:54 PM
Who's eleven, mine or yours ??

John S.

12-14-2003, 06:56 PM

Really nice looking graduations on the dial. How did you cut them?


Alistair Hosie
12-14-2003, 07:31 PM
What I would like to know is how did you mark the numbers and won't the fade with time ? Alistair

12-14-2003, 08:15 PM
I used a Dremel tool mounted in a bracket on the compound. The Dremel had a pointed cutter in it. The spacing was done with a fixture which engaged the teeth on the saw blade. The length of the marks was done with a carriage stop. Here's what it looked like.

The vernier was done on the milling machine to get the slightly different spacing required.


12-14-2003, 08:45 PM
I love it. Tool post (not) grinder. Wait 'till you see what I am up to.

12-15-2003, 01:07 AM
Very nicely done. The dremel (or flex-shaft)is an excellent idea - a good appplication for dental burs, actually!

One way you can clamp the lathe spindle is with a split collar on the outboard tubing of the spindle (near the change gears).

12-15-2003, 01:21 AM
The numbers were done with a Sharpie pen. I wasn't sure which way I wanted them to go, so I used something which can be easily removed with rubbing alcohol.