Optimum MF2 Vario (Bridgeport-like) drawbar disassembly issue

Hi all,

I have an issue with my recently acquired Optimum MF2 mill. It is a Swiss-made Bridgeport-lookalike manual mill.
Unlike the original Bridgeport, this one uses ISO40 fixture in the spindle. As i actually use BT40s from my previous machine the drawbar is uncomfortably short and only engages a couple of turns at most. So i would like to extend the drawbar a little.

The issue i have is that i am unable to remove the existing drawbar. It will lift an inch or 2 but then hits a hard stop and won't lift any further. So far i haven't found any obvious reason for this. Looking up into the spindle cavity reveals no obstacles - there is a clean thread entering the spindle with no shoulder (i.e. no ball or claw mechanisms - just a thread).

At the top of the spindle the drawbar exits cleanly. The previous owner said that there had been some attempts at making a power tool change mechanism. I assume a remnant from that is a keyed bushing around the top of the drawbar. However, the bushing is cylindrical with no flanges of any kind so could not prevent the drawbar from raising out of the spindle. It is possible the bushing is original but the finish does not match so i suspect not.

Could the drawbar be a 2 part component and in such a case, any ideas how to hold the lower part while turning the upper to separate them?
Any other ideas would be welcome as well.

Or if anyone should happen to have a disassembly drawing of the actual machine, that would be perfect. I do have the user manual but the exploded spindle diagram does not show any drawbar at all.

I can provide pictures but they are rather noninformative. The only clue if you can call it that, is that there seem to be some kind of notch or notches in something below the top bushing. Since it is deep inside the spindle tube it is almost impossible to see clearly, much less to get a photo that would show it clearly.

Hi mpaalanen

Please post some photos of the mill and head I have never seen a Swiss made BP copy mill. I did a google search but all I got was a few Chinese made BP using that name.
There is a big difference between a BP copy / clone and what I would call a #1 knee and turret USA style mill. Lots of US companies and also other country's made #1 knee and turret mills.
On some of the head designs the draw bar is what I would call "captured". This allows the draw bar to not only pull the tooling in but push it out as well.
On Cincinnati Toolmasters for example some of the draw bars are two part and some are one piece. I'm not sure about the two part ones but the one piece draw bars the head needs to be split to remove the draw bar.
I have also seen other mills (Burke, Fray come to mind) that had a capture nut on top of the spindle to do the same.
Post some photos.
Andy

Here is the general view of the machine. Quite Bridgeport-like don't you think?


Here is the spindle with the VFD unit on top.


Looking up into the spindle cavity. Now that i myself see a relatively clear photo it looks like the thread is larger than the axial hole in the spindle so that may be the reason the drawbar won't move up.


Top of the drawbwar visible when the top bearing shield has been removed.


This is the amount you can pull the drawbar upwards before it hits a hard stop somewhere.

Now my first priority is not to be able to remove the drawbar but only lower it sufficiently to enable the bottom thread to engage more of the BT40 pull stud thread. If that can be accomplished by raising the bushing visible in the last 2 images, then that would do it. Assuming it is the bottom end of the bushing that limits travel downwards.

Again, all thoughts on this are welcome.

Actually, i owe an apology. Optimum turns out to be German after all, not Swiss. Someone mentioned it to be a swiss company but apparently that is not so. I should have noted the nameplate on the mill where it clearly states "Germany" in perfectly legible letters. Oh well. But photos are on the way once the moderator approves them for release.