Bridgeport Rotary Table Stand

[gatz]

Hope I don't bore any of you with this rather lengthy post....
After many years of looking for a nice-sized Rotary Table for my BP clone mill, I finally located one......a Bridgeport 12", .....right here in town, and priced reasonably.
I say that because it's the same rotary table I bought at auction in 1986 when starting a machine shop business. When I sold my interest in the business, the RT stayed there. For some reason, I remembered it and asked the present owner if he'd part with it. He said "yes" and we agreed on a price that was fair to both parties. (Still, I hate paying for something twice!)
It needed a lot of cleaning up, so it was disassembled; everything checked out OK, then re-assembled. I was a bit surprised to notice there weren't any mill marks or defacing; it was the same as when I first bought it.
The thing about 12" BP RTs is that they weren't designed to be mounted vertical without a right-angle mounting bracket of some sort, unlike a Troyke. Fortunately, a bracket was purchased soon after getting the RT in '86 just for that purpose. Horizontal or "normal" isn't a problem; you just need two of the mounting ears that typically come with it.

SO,..... How to store the RT when not in use and make it easy to mount/dismount? Thought about making a jointed arm affixed to the mill column that would allow swinging the RT out of the way. Did some checking and measuring; it would need quite a bit of room just to clear the mill column and mill bed.

But, the biggest concern was how to readily convert the RT from Horizontal to Vertical or vice versa.

Came up with this stand/cart to store the RT horizontally, but through the use of a small hand winch, the RT could be raised and tilted 90º up so that the right-angle mounting bracket could be slid under and attached to it.
The stand is on 4 casters; 2 fixed at the end nearest the mill table and 2 swivel opposite. To move the RT onto the mill table, the table is lowered until the height is about the same as where the RT is on the stand. As a safety precaution, there is a wooden dowel that is inserted to lock the left mill feed handwheel to the stand so as to keep the stand from moving away from the mill.

The stand with BP RT in horizontal position. Crank for winch is stowed in a bracket that also supports the crank rod when in use.
The winch is just visible under the top framework of the stand. It sits at 20º off the y-axis



Stand is moved so that RT can slide onto mill table, which has been lowered into position.
Right below the handle of the handwheel (and barely visible) is the wooden dowel that locks the left-hand mill feed



Here, the winch is pulling up on the 2 sliding vertical brackets that engage the 2) pin brackets that have been inserted into the top slots of the RT
This shows the RT in the transition from horizontal to vertical. The pin brackets allow the RT to swivel freely.
Fortunately, the guess of center-of-gravity was very close..... no tendency to tilt one way or the other.


Here the offset pin bracket for the RT handwheel side is shown. I wanted to make sure the degree pointer didn't have to be removed.
The other pin bracket is similar but did not have an offset.



Right-angle bracket is loosely bolted to the RT in 4) places using 5/16-18 SHCS



On the open side of the right-angle mounting bracket I bolted on another bracket that serves two purposes.




1) It is used to keep the whole assembly level when accessing the two 3/8-16 SHCS at the bottom....



Clear access to the 3/8-16 SHCS



2) It has a small box to store the fastening cap screws.



RT in vertical position ready to slide onto mill table



Right-angle mounting bracket is stored on the bottom shelf of the stand when not in use.

[DIYer]

Thanks gatz! We've added your Rotary Table Stand to our Machining category,
as well as to your builder page: gatz's Homemade Tools. Your receipt:

Rotary Table Stand by gatz

tags: stand, rotary table

[metric_taper]

I like this solution. Add a 10inch 3 jaw chuck on top, and the weight gets even funner.
I have a bridge crane in the shop, built just because of my 12" RT. I keep the chuck mounted full time, and clamp the cable hook in the 3 jaw for lifting. And for horizontal use, I got a big angle plate, as there is only a narrow flat when rotated, so I assume that was how Vertex intended it to be fixed to the table.

[Toolmaker51]

Gatz! Terrific build. Brilliant consideration of details, solution, execution and presentation. Full-on 100%'er, each aspect.

Jon? Tool of the week, right here!

[gatz]

Thanks guys.

[Ralphxyz]

Now if I only had room in my shop for a stand.

Ralph

[Toolmaker51]

Ralphxyz, you might consider his original idea, very common with vises. They'll mount a table on side of mill column, maneuvering X-Y-Z into position so the table reaches platform the fixture is parked on.
I'd add some kind of edge or pins so vibration wouldn't walk it off.
Another is like a jib, the vise jaws clamping to it; for security a tab protrudes under solid jaw in case bite is less than positive. I like those better, swinging over lowered table means no marks from alignment keys under vise. . . No jaws on rotary table? But there are clamping slots. Use two, decently spaced apart.
A little old man I know, working every day in HIS garage shop built a little crane and winch attached on top of the ram. 2 Tee nuts, 1 bar & hoisting eye, that's it.
Neither use an inch of floor space.
I haven't either, room not primary issue and bought used lift table eons ago.

[Ralphxyz]

I do have some wall space around my mill. If I could figure out how to make strong multi joint swing arms I would be all set.

Ralph

[Toolmaker51]

Ralphxyz #8 ; Far easier to space the hinges apart. just like a door. Rectangular tube arms, even hinge bosses, with plastic bushings. Pins could be about anything without threads inside the bushings. Build a decent length to trim coincidental with shape of column and level. magnets work great for this. Weld bolting plates, and drill column. 1/4 or 5/16 is plenty, 2 per plate. It's also easier to plumb, when plate shape is narrow and placed horizontally.


Next?

[gatz]

The swing-arm method was what I was seriously considering until I checked out the available space around the mill and just how much room the RT takes up.
As this would be semi-permanent, it just didn't seem to want to work out.
I was going to make the hinges like Toolmaker is suggesting.
Then bolt a substantial bracket to the mill column at a relative angle so that the hinge axis are vertical.
There really isn't a need to have the mechanism do any lifting, although I had considered it; the mill knee can take care of the height involved.

But, BUT.......that would still have presented a problem when transitioning the RT from horizontal to vertical, because to do so means tilting the RT up 90º and getting it mounted to the right-angle bracket. "Save the Toes !!"

Other brands of RTs usually (but not always) have Hor/Vert mounting capability.
The Bridgeport 12" RT is lacking in that regard, but I really like it; it's a quality piece of equipment.......so there's that.

gatz