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steverice
06-05-2012, 08:17 AM
I installed my angle head on my variable speed mill, I was tightening the draw bar, on this particular draw bar the hex is held on to the shaft with a dowel pin. Anyway the pin sheared and the hex came off, now the shaft of the draw bar is in the head of the mill about 6 inches down in the hole of the head, any suggestions on how I might be able to get it out. I am freaking out.

Thanks in advance

s.r.

Peter S
06-05-2012, 08:47 AM
SR,
Assuming the hexagon end of the draw bar is also the shoulder it tightens on....could you angle the mill head (or swing the whole ram clear of the table if your mill does that) and drop the whole lot out the bottom of the spindle i.e. remove the right angle head with draw bar still attached.

I suppose it is tight in the taper, so put a length of bar down from the top first and whack the drawbar to free the taper.

J Tiers
06-05-2012, 08:50 AM
Does not this drawbar hold a collet etc?

Therefore, cannot the collet or whatever come out the end of the spindle?

if the drawbar and whatever it holds are driven out together by tapping on a rod in the end of the spindle, you should be OK. It's also possible that if it is a collet, which presumably is holding something, it can be partly drawn out by removing (twisting and pulling out) whatever it is holding.

If that doesn't dislodge the collet, it will at least remove the clamping force and make it easy to push out.

Ian B
06-05-2012, 08:54 AM
Peter,

I'm just guessing, but if it was a case of put a drift down the spindle and give it a whack, he'd probably have thought of that. Could the problem be that, below the hex, there was a collar, and it's this that's tight against a shoulder in the spindle, ie. the tool is still firmly held in the spindle with the drawbar in full tension?

If so, ouch.

Hare-brained solution #1:
Turn the head through 180 degrees, exactly upside-down. Clamp a suitable sized drill in the vise, pointing upwards.
Run the spindle backwards, and use the quill to feed the spindle onto the drill, cut just enough of the drawbar away to let it be drifted out.

If the head'll only go half way over, do the whole operation horizontally.

Ian

A.K. Boomer
06-05-2012, 09:34 AM
Without the hex doesn't that mean that the bar is able to travel further into the milling head ?


if that's the case then don't do anything but drift the draw bar further in with a wooden dowel, it will then totally expose the angle head so you can rotate it off the drawbar and then just remove the drawbar out the bottom of the spindle - You may have to tilt the mills head...

Peter S
06-05-2012, 09:42 AM
Ian,

Yes, my apologies to the OP (and other readers) for offering such an obvious 'fix', but I can only recall seeing two-piece draw bars of simple construction i.e. a single diameter draw bar pinned to a larger head. I am no doubt about to learn there are other ways of doing it! :)

sasquatch
06-05-2012, 09:43 AM
A couple of pics if possible would be of benefit here.

A.K. Boomer
06-05-2012, 09:48 AM
Ian,

Yes, my apologies to the OP (and other readers) for offering such an obvious 'fix', but I can only recall seeing two-piece draw bars of simple construction i.e. a single diameter draw bar pinned to a larger head. I am no doubt about to learn there are other ways of doing it! :)


I don't think it's just you - I think were all stating the same thing,

guess we'll find out in short order...

steverice
06-05-2012, 12:55 PM
Thanks for the replies, Yes the drive is tight (or as tight as it would get until the pin sheared) the hex in it's entirety came off so perhaps it will come out the bottom. To tell you the truth I was so freaked out about this that I didnt think about that although I had just given it some thought right before I signed back on to see if I had any responses. I am going to finish the machining process I have going then give that a try.

Will let you know the out come.

s.r.

Ian B
06-05-2012, 12:59 PM
AK,

Yes indeed, re-reading the first post, it does just sound like a parallel shaft & a cross pin which would drift out (or even fall out if spoken to harshly). I hope for him that it is.

Mind you, that wouldn't be any fun, now would it?

Waiting with baited breath,

Ian

Jaakko Fagerlund
06-05-2012, 01:06 PM
I am going to finish the machining process I have going then give that a try.
I would NOT continue if the hex head really was the piece that kept it in tension. You may risk your tooling & health by using it.

lakeside53
06-05-2012, 01:08 PM
There are very few draw-bars without a pin. BUT... the shaft is supposed to be an interference fit onto the head, then the pin. The good bars wll have a grooved solid pin, not a roll pin. I just made another for my Kurt air-bar (Kurt supplies the parts - you machine them to suit the length if like mine it's non-standard), and found out how tricky it is to press a head onto a long 7/16 4140 rod without it bending! (use a pipe fixture). Next time I'll also use moderdate heat.

If you need to buy another, rather than the slew of cheap imports and some marginal "Made in USA", check out the Dorian bars on Enco. I have a couple of these for manual machines.

lakeside53
06-05-2012, 01:09 PM
I would NOT continue if the hex head really was the piece that kept it in tension. You may risk your tooling & health by using it.


The draw bar isn't required after the taper is set. This of course assumes both tapers are dry (no oil), clean and... but in general it isn't an issue. The question is whether the taper was really set before the pin sheared.

lakeside53
06-05-2012, 01:14 PM
I installed my angle head on my variable speed mill, I was....



I assume you know you need a draw bar with longer hex end when using the RA attachment?

Mcgyver
06-05-2012, 01:18 PM
Ian,

Yes, my apologies to the OP (and other readers) for offering such an obvious 'fix', but I can only recall seeing two-piece draw bars of simple construction i.e. a single diameter draw bar pinned to a larger head. I am no doubt about to learn there are other ways of doing it! :)

I don't that that is inappropriately obvious advice at all, in fact its probably the state of affairs. The OP is "freaking out" and what is obvious or not is a function of experience. It would be a sever design flaw if the remaining part of the draw bar couldn't be pounded on to release the taper as those pins do go eventually. If it was the case, shame shame shame on the designer...and how are you at long hole drilling? :D kidding, almost assuredly you'll be able to pop a length of rod in there, give it a smack and release the tapered tooling.

lakeside53
06-05-2012, 01:24 PM
Support the RA attachment before you drop 30lb onto the mill bed!

steverice
06-05-2012, 02:52 PM
10-4

s.r.

Black_Moons
06-05-2012, 02:57 PM
Thanks for the replies, Yes the drive is tight (or as tight as it would get until the pin sheared) the hex in it's entirety came off so perhaps it will come out the bottom. To tell you the truth I was so freaked out about this that I didnt think about that although I had just given it some thought right before I signed back on to see if I had any responses. I am going to finish the machining process I have going then give that a try.

Will let you know the out come.

s.r.

Please don't machine anything with a sheared drawbar. That thing keeps your tool in, without it your tool WILL work loose in short order and you'll get that drawbar out much sooner then you wished.

Black_Moons
06-05-2012, 03:00 PM
The draw bar isn't required after the taper is set. This of course assumes both tapers are dry (no oil), clean and... but in general it isn't an issue. The question is whether the taper was really set before the pin sheared.

*maybe* with MT taper, but not with R8 taper. And I still would not chance it.

lakeside53
06-05-2012, 03:37 PM
Nothing is going to come out in this case -the RA adapter is clamped to the quill. There is zero side to side tool pressure on the drawbar R8 - is all on the horizontal R8 of the adapter.

A.K. Boomer
06-05-2012, 03:42 PM
Nothing is going to come out in this case -the RA adapter is clamped to the quill. There is zero side to side tool pressure on the drawbar R8 - is all on the horizontal R8 of the adapter.







No way!!! Listen to Jaakko !

the second the collet is under any torsional load to speak of you will pop it out and shear your spindle alignment pin -------- DO NOT USE...

I thought he was joking when he stated he was going to finish the procedure...

lakeside53
06-05-2012, 03:53 PM
You keep those pins in? :D

I must be luckier then most them - my drawbar had been out for 2 months while I found the time to make a new one. All that time I had an R8-ER32 in the spindle. Lots of work in that time.

A.K. Boomer
06-05-2012, 04:08 PM
Its not worth the risk -- your assuming his taper is oil free as you stated - many of us run a thin layer of oil to aid in not only the clamping pressures but reduce taper wear,

If it pops under load he can be looking at a massive burr inside the spindle area to where the collet will have to be hammered out and no other collets will go in...

camdigger
06-05-2012, 04:16 PM
I installed my angle head on my variable speed mill, I was tightening the draw bar, on this particular draw bar the hex is held on to the shaft with a dowel pin. Anyway the pin sheared and the hex came off, now the shaft of the draw bar is in the head of the mill about 6 inches down in the hole of the head, any suggestions on how I might be able to get it out. I am freaking out.

Thanks in advance

s.r.
Steve
What kind of mill????

When this happened to me on my CHICOM milldrill, I just removed the hex section, placed a hunk of plywood over the work on the table, and tapped the end of the drawbar to release the taper. When the taper released, I unscrewed the endmill collet and pulled the fubarred drawbar out the top of the head.

Finding a replacement drawbar wasn't a big issue as the distributor simply robbed one from another mill they had in stock.

Freaking out isn't worth it, BTDT and survived....:D

steverice
06-05-2012, 07:46 PM
I brought the table up to the RA drive, loosened it up, got up on top and smacked the draw bar to break it loose then dropped the table while it was supporting the RA. Luckily the draw bar came right down with the drive and when the table was low enough the drive swung out of the way and it came right out.

Thanks for all your guys input and I am glad I was able to add to today's entertainment.

s.r.

philbur
06-05-2012, 07:58 PM
An R8 taper has a taper angle that is self releasing, if everything is correct then it should just fall out. If it doesn't then you are lucky, or unluck, depending on your point of view because it will be hanging in there by the skin of it's teeth.

Phil:)