I'm a long term lurker but first time poster and I have a question about Bridgeport heads that I'm hoping someone might be able to help with.
In my home shop I have a Korean stepped pulley Bridgeport clone that was made in the mid 80's and looks identical to an original Series I Bridgeport. It's a great machine that was reconditioned a couple of years ago, and so close in appearance to an original Bridgeport does it appear to be that original Bridgeport parts were used to refurbish the head without any problems.
A couple of months ago a friend gave me a variable speed Series II head that came out of a large production factory where he works. It was apparently an accessory for a large Bridgeport horizontal mill that was being scrapped, and as far as I'm aware this variable speed head has done very little over the years other than sitting around getting incredibly dirty.
I'd like to replace the old stepped pulley head on my machine with the Series II head, but the problem for me is the spindles. The Series II head has a standard R8 taper while my clone has an ISO 30 taper and changing to the Series II head will obviously mean none of my current tooling will be suitable.
Of course, I could just bolt the Series II head on and buy some new tooling, but I've collected quite a bit of ISO 30 stuff over the years and replacing it all would be costly. I also wish to avoid adapters as they can make life complicated.
What I was wondering is how interchangeable are the top and bottom halves of Series I & II Bridgeport heads?
What I was thinking is that if I could transplant the variable speed top half of the Series II head onto the bottom half of the old stepped pulley head I'd kill a couple of birds with one stone in that I'd retain the use of all my tooling and benefit from the new bearings that were fitted to the old head not long ago and that have not done much since.
I appreciate that the old machine isn't a genuine Bridgeport and there may be problems associated with that, but what I was hoping to find out was that assuming for a moment that the old head was identical to a Bridgeport stepped pulley head would such a swap be possible?
Any help would be greatly appreciated,