Tom Senior M1 milling machine drawbar sizes?

[Smouser]

I would like to make new drawbars for a Tom Senior M1 milling machine (vertical and horizontal) but I don't have a clue what the originals looked like or what their length is supposed to be.

Can anybody please share a couple of photos and possibly the dimensions of the drawbars?
I could copy the same style drawbar my Elliott mill has, but I would like to see some original drawbars before committing.

Shamelessly copying in people who I believe have some Tom Senior millls.

@brewdexta @W.olly @Arc Tourist @Rannsachair @citizen kane

Thanks in advance!

 

[Arc Tourist]

I'll post some photos and dimensions for you.

 

[brewdexta]

I'm away from the mill until Friday, I'm pretty sure you'll get what you need by then, but if not, then I can take a look.

 

[Arc Tourist]

Ok, here you go. First I have to qualify that my mill has a Morse 2 taper for the vertical head, and a No. 30 International taper for the horizontal.
The vertical drawbar is 3/8" in diameter and 12" inches long, with 3/4" of an inch of threading on each end. Washers / spacers are used as some of my milling holders have varying internal thread depth.

I couldn't locate my horizontal draw bar, but the same diameter of 3/8" is used; so, I slid a welding rod with a hooked end through the mill and marked the length, deducting for the length of the Int. 30 portion of the fitting, and adding an inch for thread, which comes to 16 1/4" inches. The thread on the draw bars you are making will obviously depend on the tooling requirements. If Metric, it should be no problem using 10mm rod for the drawbar's.

Here are several photos, sorry a couple are slightly blurred, I really need to get a modern camera. Anyway, hope this helps.

 

[Smouser]

@Arc Tourist amazing!!

I did not mean you need to do it right now!

My vertical is the same as yours, the horizontal is 3 Morse Taper.

Thank you for the photos!

 

[Rannsachair]

Sorry mines a Light Vertical, not an M1

 

[Arc Tourist]

@Arc Tourist amazing!!

I did not mean you need to do it right now!

My vertical is the same as yours, the horizontal is 3 Morse Taper.

Thank you for the photos!

No problem, I would rather be in my garage anytime.

 

[Agroshield]

If metric, it should be no problem using 10mm rod for the drawbar's.

It might not be that simple. The majority of 30 taper tooling is 12mm or 1/2" thread. If you made a drawbar for this tooling as M10, it makes making the reducing bush somewhat challenging. It would be better to go down to M8.

What it might be better to tell us is what is the maximum size that will pass through the spindle bore of the two heads.

What determines best drawbar length and thread is the tooling that is to be used in the spindle. If this is unknown, or to give maximum flexibility, it could be better to make the drawbar a little long (e.g. to suit ISO30 and BT30) and then make spacers that go under the bolt head* so the same drawbar can be used with anything. Similarly, make the drawbar with a small thread such that any bush can be used in the tooling (again, 30 taper comes in M12, 1/2" UNF and 1/2" BSW, so an M8 thread would fit all three bushes).

* A C-shape means you can insert or remove the spacer without pulling the drawbar (with the horizontal spindle, there is a possibility you have to pull the whole machine forwards to get the drawbar out; with a Bridgeport with a riser block, you need an oxygen mask to go that high). A couple of embedded magnets could also help it not drop on the floor.

 

[Smouser]

Next problem, can't get to the lathe because the mill is blocking it

 

[RichardM]

If you send the mill to me you won't have that problem and will be able to laugh at me trying to fit it in my garage.

P.S. I also have a 10mm drawbar as well as the 3/8ww on my S head, just needs the diameter relieving to 3/8 just after the threaded section.

 

[Arc Tourist]

............................... What it might be better to tell us is what is the maximum size that will pass through the spindle bore of the two heads.

What determines best drawbar length and thread is the tooling that is to be used in the spindle. If this is unknown, or to give maximum flexibility, it could be better to make the drawbar a little long (e.g. to suit ISO30 and BT30) and then make spacers that go under the bolt head* so the same drawbar can be used with anything. Similarly, make the drawbar with a small thread such that any bush can be used in the tooling

My mill is the Major ELT model with the S- Head, which as the capability to take a 10mm diameter drawbar, and the horizontal can accommodate a 1/2" inch drawbar; both with a close slip fit. A drawbar with a longer threaded portion for universal use would not be an issue with the vertical S Head, but it could on the horizontal, as too long could interfear with closing the rear belt enclosure.