# Bridgeport m head question



## Ed T (Aug 7, 2009)

Hi, this is my first post on this forum, so thanks in advance for any feedback. I have a Bridgeport M head machine with a dovetail ram that was originally built in the late '50's. It's in fair condition and, generally, adequate to my needs. However, the tooling limitations imposed by the relatively small collet capacity is becoming more anoying all the time. I want something with R8 capability because there is so much stuff out there for that format. There are a number of options available. My question is whether the mounting flange on the J heads is the same as the mounting flange on the M's. It looks like it, but someone out there probably knows for sure. An adaptor plate could be made or a swap at the knuckle might work, but maybe it's simple once I find a J head. Thanks for any feedback.


----------



## Holescreek (Aug 7, 2009)

The newer dovetailed ram bridgeports have a pad on the back of the ram which is the proper size for mounting an M-head flange. Does your V ram have this feature? If it does, and it matches what you have in the front, you're in!

Unfortunately I cannot directly answer your question because I have a J-head mounted on my old round ram M-head base. The round ram has the same mounting pad on each end of the ram.

It can get pretty confusing. Take a look at the bridgeport listings at plazamachinery.com. I have dealt with Joe several times and you can always email the question to him. If you need something odd, he usually has it. -Mike


----------



## Ed T (Aug 9, 2009)

Mike,
  Thanks for the input, The ram has a very different feature on the end opposite the head than on the head end. It is disc like, about 4" dia and 2" thick with the flat sides parallel to the ground. It's machined to accept something, but I'm not sure what. I know that BPT had some auxilliary tools that could be put on there, but it definately will not fit the head. I'll check ut PLAZA. That's where I got the parts to convert to 120 1Ph some time ago.


----------



## Holescreek (Aug 9, 2009)

I'm sure you have already been to Tony's site and looked around but if not, http://www.lathes.co.uk/bridgeport/

HEre's a photo of an adapter I made to mount a J-head onto the M-head round ram. The OD of the back of a J-head is 7.5" and requires a radial (circular) T-slot for the t-bolts that is 6" in diameter. Ignore the 4 pins in the t-slot, those are pull dowels that I used to attach the back "wings" for mounting.














All of the machining in the photos above were done with the M-head and a 9" rotary table. -Mike


----------



## Ed T (Aug 9, 2009)

Mike,
   WOW!! What a nice looking set of parts. You must have REALLY wanted to swap out the head. I have been to Tony's site and it is very informative. The machine I have looks just like the one on the link you attached. (The one at the bottom) The implication of the acompanying text ("The model was identical to the BRJ but fitted with the lighter Model M Head") is that the interchange I have in mind will probably work. The head I am looking at is atop an old T-ram tracer machine that has been tipped over and the rigid ram is tweaked about 15 degrees out of alignment The ram on those machines is not intended to turn in that axis as far as I can determine. Anyhow, I'm just trying to avoid dragging 2000 pounds of iron home only to find that it doesn't fit together with the 2000 pounds I already have. I'll get ahold of Plaza this week and see what light they can shed on the topic. Thanks for the help and, again, that is a beautiful set of parts. I hope my swap will be simpler.
Regards,
Ed Taylor


----------



## hmember (Aug 11, 2009)

Saw the topic heading and said to myself "If that's a post regarding a Bridgeport M head and there's nothing from my friend Mike "Holescreek", I'd better call an ambulance. And he did not disappoint.

I haven't checked, but I'll bet it bears out -- whether on this forum or any other, if the topic is Bridgeport M heads, the odds are better than even that there is or will be a knowledgeable response from Mike. :bow:


----------



## Holescreek (Aug 11, 2009)

:idea: Your grammer gave your identity away! 

Having an "extra" M-head stored in the other shop doesn't make me an expert on anything but how to take one off. Rof}


----------

