changing bridgeport round ram to dovetail

[chip's]

Has anyone had any experience in changing a round ram to a dovetail, or any good ideas on how best to do this?

Thanks

[Forrest Addy]

Find a top turret with ram and knuckle?

[lazlo]

Forrest, is the turret top the same? I though the turret top on the round ram was smaller?

[oldtiffie]

Has anyone had any experience in changing a round ram to a dovetail, or any good ideas on how best to do this?

Thanks Chip's.

Please post a pic or two as it is guess-work here at least. Include a few critical or illustrative dimensions too.

If I understand you correctly, the ram is on the top of the mill body as is a BP and moves in and out with the turret vertical head on top of it.

If you are just trying to stop the ram rotating, why not at least consider fitting a key and keyways - as in a vertical mill head/quill arrangement?.

Does the head/turret need to rotate left-right? Or can/will it if the dove-tail or keyways are fitted?

As said, I am guessing until I see a pic or two.

[chip's]

I will try and get some pic's as soon as I can. What I am trying to do is either change the turret, (which is a different mounting on the round ram than the dovetail. The round ram has t bolts from the turret going through the column, the dove tail uses a spider with bolts going down through the turret.) or figure out some way to tilt the head forward and back. The head tilts fine side to side but there are times I need forward and back. I have a dovetail turret and ram to install, if I can get a good way to mount it. If I could find a transitional turret Bridgeport made, that would be great, (this would be my first choice) but they are hard to come by. I am making a transitional donut as a way of doing this but I am not sure this is the best way to go. I am grateful for any thoughts or ideas.

Thanks to all.

[DR]

This is an easy conversion....

Put the round ram on CL.

Buy a dovetail machine.

Other wise forget it.

[Rich Carlstedt]

My 1943 Bridgeport was a round overarm M head machine.
I converted it to a dovetail J head about 30 years ago

These early machines had columns and turret heads with the turret clamp nuts inside a notch in the column. When Bridgeport came out with the Dovetail ram and J head ( 1948?) , they continued to use this turret spider and column setup,
but created a new turret for dovetail operations.
Around 1967 (I think?) they changed the columns, so the turret spider clamp is done from the top, as you have it to this day.
( see
http://machinebuildne.com/
for this modern day setup)

What you need to do is find a BP that was made from 45 to 67 and use that Dovetail turret. As long as clampnuts are NOT ON TOP OF THE TURRET
It is a drop in,swap out, without any modification, Except the zero point change on turret rotation. Mine moved about .100" ( This is a metal tape around the turret on new machines, mine was engraved in the turret)
When BP went to the new column, round overarms were not available.

Rich

[rantbot]

The head tilts fine side to side but there are times I need forward and back.

I suppose you have a J head.

The mound-ram mills with M heads (and C heads, and R heads, etc) had that feature. When the much heavier J head was introduced, Bridgeport hung it on a ram with a flat flange on the end rather than a clevis, so the nodding motion was no more. It came back, of course, when the dovetail ram was introduced.

[chip's]

Yes, I have the J head on my round ram now. I just need the forward and back tilt now and then. I had a hard time finding a mill when I was looking. I looked for three years to find this one. Most of the ones I could find were out of my price range or too far away. This one was 15 miles from me and I could borrow the neighbors truck to go that far. I managed to get the new ram, turret and knuckle on a trip. The folks I was staying with offered to bring it to me in their small pickup the next time they were coming to visit us (which was in a month) so it was a done deal.
I would like to convert this even if it is a pain. It has been a good machine and others are just too hard to come by. I have all the parts except the old style turret.

[Rich Carlstedt]

Here is a photo of my 1943 mill with the ( 1960 ?) J head and dovetail updated.
Note the location of the turret clamp bolts inside the column cutout.
This is the big difference between old and modern turrets
This allows dovetail interchange with any "early" column.
Rich