BB2V Draw Bar

I recently got a Hardinge BB2V mill, that came with collets, but no collet closer draw bar - Obviously, I need to make one.
Does anyone have a draw bar they could measure? It would help me get started.
I know the collets have a 7/16"x26 internal thread, but that's about all I know :~)

Thanks.

Easy couple steps.

Thread the end of a rod to fit the collet.

Slide rod through spindle, thread on to a collet, use a sharpie to mark where it comes through.

Cut off leaving some to spare.

Thread it. Make matching nut.

Screw nut down until collet will tighten. Cross drill and pin the nut end.

Done. Unless you want to have a through hole, in which case you rinse and repeat all steps, and solder or use permanent Locktite to secure the nut.


Why is it folks always seem to want someone else to measure what they have, rather than simply measuring what is right in front of them in the first place?

Well, I figured someone would just tell me to do that - Pretty much what you'd need to do to make any kind of basic drawbar.
I was just hoping someone might have an original to show, as I've never actually seen one, except poking out the top of one of those mills, in a photo of the whole machine.
No big deal in any case, as I'm going to have to cobble up something, just to use the little mill.

Tom A said:

Well, I figured someone would just tell me to do that - Pretty much what you'd need to do to make any kind of basic drawbar.
I was just hoping someone might have an original to show, as I've never actually seen one, except poking out the top of one of those mills, in a photo of the whole machine.
No big deal in any case, as I'm going to have to cobble up something, just to use the little mill.

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I'd suggest looking at DOM steel tube, or even aircraft tubing for stock, if it can be found with a reasonable wall thickness.

I think there are still a fair few suppliers out there capable of supplying a suitable hand knob, if you do not wish to use just straight hex stock for a nut.

trevj said:

I'd suggest looking at DOM steel tube, or even aircraft tubing for stock, if it can be found with a reasonable wall thickness.

I think there are still a fair few suppliers out there capable of supplying a suitable hand knob, if you do not wish to use just straight hex stock for a nut.

Click to expand...

This drawbar is different from most Hardinge ones, in that the collets have only an internal thread, so the drawbar will need an external threaded lower bar section, and a larger dia. upper part, which could be a section of hex stock, shouldered against the top of the spindle, with a handwheel or knob on top - And knowing Hardinge, the original probably also had a thrust bearing at the shoulder .

I took a couple pictures of mine. I bought my 1936 BB2V about 35 years ago and have never run it. It has the common type of iron knob that Hardinge started using in the mid-1930's. Hardinge made wrenches to fit these knobs.

The threaded portion is shorter than original. It will grab a collet, but I would want more thread engagement if I were running the mill. It appears that a previous operator had a 3/8" double-ended end mill get caught in a cut and spun in the collet, perhaps while feeding the table upwards, cutting away some threads on the end. Don't do that.

The thick portion that goes through the hole in the top of the housing is 1.00" diameter x 1.50" long. Then there is a .5085" diameter that is probably a close fit in the spindle x .94" with an undercut at the top. The rest of the bar is .438" diameter x 4.35" long from the big step at the top of the spindle. The remaining thread length is about .35" and I did not try to figure out the original length, but the collets are threaded for about 7/8" deep. There is a .253" hole in the end to allow small and long double-ended end mills to pass clear through the collets. I have some long 3/16" shank double-ended end mills that would need the hole in the draw bar.

In the older machines, Hardinge did not use a ball thrust bearing in the draw bar. They used an oiled red fiber washer, a sort of hard rubber/paper type of material about 1/16" thick. There was no washer in my BB2V mill.

Larry

Larry, I love you!
That is the exactly the info I was hoping for, and then some.
I doubt I can duplicate the lovely Hardinge cast iron handwheel, but I think I can come pretty close in function. And, maybe, if I feel really ambitious, I can try to see what I could do in steel or aluminum - I do have another mill, and a dividing head - A worthy project........

Many thanks,
Tom

Tom, that hand wheel is a pretty easy lathe job, with a bit of milling (drilling most likely, actually)to make the grip grooves.

Note that the 'grooves, are actually drilled holes, that were then profiled off in the lathe!

All the dimensions you need are right there on the machine in front of you, the rest, isn't important enough to need tolerances!

The threads on mine are 11/16" I have a very flat oil impregnated fiber washer. And mind doesn't have any through holes in the handle.

Ron

Shiseiji said:

The threads on mine are 11/16" I have a very flat oil impregnated fiber washer. And mind doesn't have any through holes in the handle.

Ron

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"mine" argggg.

Thank you, Ron!
The more I look at the photos, the more it looks like a very do-able project - I might even be able to make one that sort of resembles the originals - We shall see :~)

Tom, also thinking that Ron's workbench resembles his own, with Ron's being a little less cluttered .....

LOL, you just happen to see it "after" it's been cleaned.

The maximum OD of the knob is 3.25 inch and the width is .87 inch.

The first time I had to make a Hardinge draw bar from scratch, I selected a hard plastic caster wheel to use for the handle. It looked factory-made, though not like a Hardinge, as I found out as my collection expanded. That first Hardinge looked like a giant version of a watch lathe. My watch lathes all had original draw bars with plastic handles, so plastic seemed right. As I acquired original Hardinge lathes, I found that most of the Chicago lathes (1903 to 1930) did have plastic handles of a toroidal shape. Some time before 1936, the Elmira machines got the iron handles with the wrench notches.

Larry

Thank you again, Larry !
The P.O. of my BB4 made a drawbar for the 4C collets , from a piece of black iron pipe, nicely threaded internally, turned smooth on the outside, and with a thick disc of aluminum for a handwheel - He left the pipe threads on on the handwheel end, and just threaded the center of the handwheel for NPT, and epoxyed it.

It just goes to show that there's a number of ways to do this stuff, both fancy, and otherwise - It's what makes it so interesting :~)