Bridgeport head question

Noddy · 2012-03-26T10:39:52+00:00

Hi All,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...

Mar 26, 2012 20 Replies

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Thanks for that DoN.

I did a quick tear down of the vary speed head on Tuesday and unfortunately it's in sad shape. My friend was told that it had done little or no work, but it's quite obviously been worked to death with very little maintenance and it needs to be fully rebuilt. Given that the only reason for trying this swap was that it was hopefully going to be a no (or very low) cost option I've now ruled out ever using the vary speed head and will try to sell it and put the funds towards a VFD conversion at some future point.

Oh well. Nothing ventured and all that hoo hah.....

Thanks to everyone for their help. It's been greatly appreciated.