"Jon Elson" wrote in message
ervers.com...
ATP* wrote:
"Jon Elson" wrote in message
rvers.com...

ATP* wrote:

Will the newer 4 HP Series II heads bolt up to an older (1978) Series
I? If so, is there any loss of working height or does the bottom of the
spindle end up in almost the same place? Thanks.

I'm no expert, but VERY unlikely! I did a round-ram M-head to J-head
update, and while VERY worthwhile, it was no bolt-on swap. the bolt
circle was totally different. I suspect it would be the same on this.
There's both a height difference and a "throat" difference to be
concerned with. Also, you need to consider the WEIGHT of the head.

Jon


Thanks. I haven't seen the machines side by side in a while and didn't
realize there was a huge difference in size. I moved the headless
Bridgeport into my garage last night, avoiding tonight's snowstorm. Slid
it off my landscape trailer and rolled it into place. Not too bad of a
move, really. It's a 9 x 42 with 12" y travel, B'port power feed. Now
it's time to get to work on the chiwanese heads.

I've got a 1 HP 1J head. It seems to be PLENTY of power for me! I had
something pull loose from the vise, and after I'd shut the motor OFF,
it twisted the head to about 45 degrees, with the end mill working up the
side of the part, and me ducking for cover, expecting hot shapnel!
I can't imagine how any machine with swivels in the head mount could
really use much more power than that.

Most of the Series II machines had a rigid mount for the head.

Jon

Probably a marketing thing. It seems like manufacturers have been boosting
the HP of the motors without changing anything else.