Fitting a power drawbar to a BOSS3?

[damae]

Is it possible to fit a BOSS3 with a power drawbar?

It's funny that I bought a power drawbar kit for my BP BOSS3 without looking closely (with a flashlight, down into) the top of the spindle. Peering down in there, I see some kind of spline about 4" down the tube that occupies the space a drawbar normally would. So am I missing something, or were the BOSS3 machines not capable of using a drawbar?

Currently, I don't use a drawbar at all; my tools lock in place with a special spindle nut. I have a 30-taper spindle, but find that not all NMTB 30 toolholders will fit due to the funny flange requirements of my spindle nut.

Some tools, like my ER32 collet holder and other large toolholders can only be held in place with the drawbar.

Any experience or help here would be greatly appreciated!

[damae]

Maybe pictures will yield some ideas.

As you can see in the first picture, it looks like a drawbar would bolt-up, no problem. Looking down into the hole, it's apparent that something is already in there.

Both the splined shaft and the wall of the hole turn with the spindle. If you want a challenge, put your eye on top of that hole and try to reach the spindle to turn it at the same time! Don't forget to hold a flashlight with your free hand -- you didn't need it for balance anyway!

So, armed with pictures does anyone have a clue what is going on with my spindle? Can I use my power drawbar?

[Hood]

The splined bit is your spindle. On the manual Bridgeports that use a drawbar they have a hole right through the spindle, on the CNC mills that use the QC tooling there is a solid spindle so you cant put a drawbar through them
Hood

[damae]

Thanks Hood. It's bad news, but at least now I know. Hopefully this thread will save another early BOSS owner the mistake of buying a power drawbar. =)

[Kevin Taylor]

Damae Watch out when you buy holder's If you have ones that the flang is to long I could grind them down for you I have a crankshaft grinder that I do OD grinding in I have gotten My boss3 going and I bought some extra holder's from ebay but I got lucky and there the same flang thickness . Good luck kevin P.S. If you have a power draybar to sell let me know I need one for my Lagun Thank's Kevin

[Barry_ward]

Hey D,

Looks just like the end of my Shiz drawbar. Try a socket, spin it. You should be able to reach up to the threaded end in the taper (assuming NMTB).

My power drawbar end effector is a 1/2"square to spline (female to female) brass coupling. The impact sticks into the square. The coupling has about a 1-1/4 od and is held into a cylinder (bearing) with an internal retainer clip.

The impact wrench and coupling come down (via air) to engage the splined top of the drawbar (when the spindle is up).

I'd probably build one if I needed another. It's fairly simple.

Barry

[machintek]

The Quick change 30 spindles had a hole through them. the tooling had a 1/2 inch by 16 thread.
The Quick Switch 200 did not have a hole though the spindle.
Therefore which do you have?

George

[Hood]

George
Maybe the UK ones are different but I have the B.E. QC30 and there is no hole.
Hood

[machintek]

Hello hood!
As always, the other side of the pond has to be different. Or is this side different?
I have installed many powewr draw bars on the BOSS series of CNC machine ( except the BOSS 7.2). The standard question was what spindle do you have? QC-30 then it can work. Universal quick switch 200 and the answer is no! Typically the QC30 nut comes off and replaced with a skirt and longer drive keys. The skirt to protect the operator from otherwise exposed keys. The keys need to be lomger to orient the tool into the keys before the draw bar is actauted.
Hood, I hope your Christmas was all you wanted it to be and I extend my best wishes for the new year.

George

[Hood]

We always have things different at this side of the pond but who is correct is open to debate
Christmas was great, would have been better if my bits and pieces to do my Lathe retrofit had arrived from the USA but thats my fault for not ordering earlier
Hope you too had a good time.

Hood

[damae]

Thanks all, for the discussion and info!

George, this is a QC30 spindle I think -- it uses flanged toolholders that look identical to NMTB 30 and lock in place with a spindle nut. I included a picture of a ER32 collet holder (from ebay) that I had to turn down in order to fit the spindle. Unfortunately, I got ahead of myself with the lathe and turned down the flange too much. Now it won't fit unless I can secure it with a drawbar.

Perhaps I'm confused on which spindle I have. If I really do have the QC 30 spindle, then the splined shaft I am seeing is removable?

I hope that the pictures make identification easy. Thanks for the help!

Originally Posted by machintek The Quick change 30 spindles had a hole through them. the tooling had a 1/2 inch by 16 thread. The Quick Switch 200 did not have a hole though the spindle. Therefore which do you have? George

[Hood]

damae
It certainly looks like the QC30 to me but as I have never seen the quick switch I cant say for sure. If it is the QC then the reason your holder wont fit is the flange thickness is too small. The normal Int 30 holders have a flange Dia of 50mm and a thickness of 8mm, the QC 30 have a Dia of 46mm but critically the thickness is 8.76mm. As you have found out the 8mm is too thin to grip in the QC30 system
Hood