[hoss2006]

Hey Gang,
Can anyone tell me the total length of the R8 drawbar for the X3?
Also, any source to buy a replacement?
Grizzlytools shows one in their parts list but doesn't give the length.
Thanks Hoss

[rustamd]

This seems like the one:

http://littlemachineshop.com/product...3018&category=

[hoss2006]

OK Great, thanks.
Still would like to know the length first to see if it will work for what i had in mind.
Thanks Hoss

[rustamd]

i know it can be hard to find length of draw bar online, unless someone has posted on forum or something. Couple weeks back i was trying to find length of Bridgeport M head draw bar to make my own, but had no luck, ended up buying used one localy

[M100]

From a UK supplied X3 R8 with metric leadscrews:

Length from bottom of head to end of thread 10.75" 273mm
Threaded length 1.25" 32mm
Thread 7/16" - 20tpi (UNF)
Head across flats 17mm

[hoss2006]

Thanks M100,
As I was thinking it's a little long for what I want.
I made my own about 6 5/8 long.
Can you guess what it's for?
Power Drawbar.
Step one of the ATC.
Hoss

[digits]

Thanks M100,
As I was thinking it's a little long for what I want.
I made my own about 6 5/8 long.
Can you guess what it's for?
Power Drawbar.
Step one of the ATC.
Hoss

Very nice I look forward to seeing this ATC project unfold.

Have you sorted out mist/flood coolant yet - I would have thought that it's essential if you want to run unattended?

[Juicebox]

Thanks M100,
As I was thinking it's a little long for what I want.
I made my own about 6 5/8 long.
Can you guess what it's for?
Power Drawbar.
Step one of the ATC.
Hoss

Hoss,

I know I'm 10yrs too late on this but do you by chance still have a drawing for this? I had purchased the ATC DVD and All X2 prints years ago but I alas I cannot find a drawing for the draw bar itself. I'm having a hard time sourcing a draw bar of the right length.

Also, all of your sites are down (g0704.com and hossmachine.info). Is there a way I could either download them or something so you don't have to host them any more. I use the site often for reference material.

-Brian

[hoss2006]

Hey Digits,
I decided on flood coolant with an enclosure made from wood covered with a
few coats of Herculiner liquid truck bed liner.
The ATC will be a little more fun to tackle so I'm gonna do it first.
Hoss

[ZipSnipe]

Hey hoss, just take a depth gage stick it in the spindle upside down , get that measurement , then measure from the top of the drawbar nut to the bottom of spidle and deduct your first measurement.

[RedDog22]

Hey Hoss. Great to see you starting this! I cant wait to see what you come up with. I'm slowly getting things on paper to start designing my own as well. A quick question. How much force is required to hold the tool holder? The LMS one says they're doing 1000lbs. Thats going to take a huge air piston to move at 100psi.

Thanks!

[hoss2006]

Hey Red,
I read somewhere that 600 lbs is enough force to hold a tool in an R8 collet.
So far I've found these cheap Bimba's at Surplus Center that put out 440 lbs.
With leverage, it should work just fine. At only $3.95, it's worth experimenting with.
Probably get a few just to have them.
The cam and lever only needs to move the collet about 1/8 inch I figure.
Later Hoss
http://www.hossmachine.com

[RedDog22]

Awesome. Thanks for the info.

(removed post because I'm stupid)

[hoss2006]

Found these spring washers at MSC Direct that look very similar
to what the LMS power drawbar uses.
I think 3 pairs would give plenty of force to hold the R8 tools.
6 washers = almost .100 deflection and 1044 lbs used like this ()()()
Might even be able to use the stock X2 drawbar instead of making a custom one.
Have to give it a try.
Hoss

[hoss2006]

Way to go Red, make me have to think
After eyeing the LMS PDB a little closer, I see they do stack 6 washers in series.
Did some research on the Belleville Spring Washer.
If you want to get out the slide rule check here.
The deflection I think I'll need is about 1/8 inch.
One turn of the drawbar to tighten the collet (per LMS instructions) = .050.
That leaves .075 to release the tool.
MSC Direct has these spring washers that will give 936 lbs of force (1674 lbs flat) and .132 total deflection
for (6) 1.750 OD washers stacked in series like the LMS. I think. ()()()
A bit pricier than the 1.0 OD ones.
I'll have to peek at the Matsura at work, Dave said it uses spring washers to retain the tools but 60,000 lbs worth.

[hoss2006]

Ok, think I'll order these Belleville washers from MSC (I already have an account).
They are metric but I get the most for my buck.
ID=12.2 mm (.480 in) just the right size to fit the drawbar.
Load=2910 N (654 lbs)
Deflection=.41 mm (.016 in)
A pack of 10 is only $6
Gives me plenty to experiment with.
I figure stacked in series ()()() should give 654 lbs with .096 in total deflection.
or
stacked series/parallel (())(())(()) should give 1308 lbs with .096 deflection.
or
()()()()=654 lbs, .128 deflection
should be able to get one of these scenarios to do the job, Eh Red?
Hoss

[hoss2006]

I figured (guess) .125 for load on the washers and enough left to release.
May only need .010 or so to release
We'll see, let the experimenting begin.
Hoss

[hoss2006]

When you loosen the drawbar by hand, it's free to move up away from the collet
because there's nothing to stop it. So then you have to tap it to release the collet.
With the cam and lever being depressed by the air cylinder against the top of the drawbar, the only way it can move is down against the spring washers.
It pushes the drawbar and collet together, releasing the tool. Voila
Hoss

[M100]

When you loosen the drawbar by hand, it's free to move up away from the collet
because there's nothing to stop it. So then you have to tap it to release the collet.
With the cam and lever being depressed by the air cylinder against the top of the drawbar, the only way it can move is down against the spring washers.
It pushes the drawbar and collet together, releasing the tool. Voila
Hoss

I can't visualize what you're saying. Due to it being a regular operation I can see how the drawbar extends upwards when loosened by hand and the tapping of it to release the collet from the taper but the rest of it puzzles me.

Any chance of a pointer to somewhere online with a cutaway drawing or a sequence of operations showing how the springs are compressed (when they appear to be completely internal to the spindle bore) and how the drawbar is tightened?

[digits]

I can't visualize what you're saying. Due to it being a regular operation I can see how the drawbar extends upwards when loosened by hand and the tapping of it to release the collet from the taper but the rest of it puzzles me.

Any chance of a pointer to somewhere online with a cutaway drawing or a sequence of operations showing how the springs are compressed (when they appear to be completely internal to the spindle bore) and how the drawbar is tightened?

If I understand it correctly, the springs are between what would be the 'nut' on a manual drawbar and (the top of) the spindle. When the drawbar is screwed into the collet, this preloads the springs, which in turn pull the drawbar upwards, securing the collet against the inside of the taper.

The drawbar is then released by pushing down on the nut, not unscrewing it.