Rotary Table Vise

[twhite]

I recently bought a 6” rotary table. I made a 10” plate for it. I am now drawing up an adjustable vise for it. I have the basics drawn. The movable jaw will pull down on a slight angle 2 deg. I need to go pickup some material later this week. Anyhow here is what I have so far.

The mounting slots will enable me to rotate 45 Deg on the fixture plate. Most likely unnecessary but did it anyways. On the fixed jaws there will be 1/4” reamed holes to locate on the reamed holes on the fixture plate.

Cutting oil is my blood.

 

[pontiac428]

Looks good, but I see an issue. First, I need to speak in terms of radius and angle.

When one clamps work to a rotary table, the most important thing is that the user is able to pick any point on the work and set it equal to center. That center, or its offset, are in terms of radius. Your (erroneously) "fixed" jaw is only moveable in increments of your hole spacing. There is no way to set an infinitely divisible radius to anything that isn't predefined with holes. You need slots to set BOTH jaws of the vise at any radius. Or else all of your curves will be in radial increments of 1 inch.

 

[twhite]

Looks good, but I see an issue. First, I need to speak in terms of radius and angle.

When one clamps work to a rotary table, the most important thing is that the user is able to pick any point on the work and set it equal to center. That center, or its offset, are in terms of radius. Your (erroneously) "fixed" jaw is only moveable in increments of your hole spacing. There is no way to set an infinitely divisible radius to anything that isn't predefined with holes. You need slots to set BOTH jaws of the vise at any radius. Or else all of your curves will be in radial increments of 1 inch.

I have thought of that. I was going to make a second set of adjustable jaws as I have on the original. With slots and jaw throw. I have a bit over 1” adjustment. On the designed adjustment jaw. Also by rotating the jaws 45deg on the fixture I then have a bit over .720 spacing as opposed to the 1” as drawn. I can also add spacer plates to get the correct offset from fixed side as designed. Not a good option.
You have convinced me to go with double adjuster jaws. Only 1 more piece of 3/4” stock. That way I can also simplify the mounting. Eliminating the dowels and a set of slots.



Cutting oil is my blood.

 

[pontiac428]

That will do it. I also like the idea of using a sine bar (or double sine "Z") with an adjustment screw on it to allow infinite divisibility between fixture holes that can easily be set with calipers or whatever. I'd hate to add a lot of work to find center of the work and the table before having to find center on the mill too. Heck, just a mill vise on a sliding track would be simple to use. By the time I get my RT set up for an operation, I'm ready to get the op done and move on, so my tolerance for fiddling is frontloaded. My take home message is it's gotta be simple and easy to set up and tear down, because not every setup operation is supposed to take as long as dialing in a barrel for a chamber cut. Gawd, wouldn't that be awful!

 

[twhite]

There is a lull at work. So instead of staring at a computer screen. I prefer to make stuff. Even if it is somewhat frivolous.


Cutting oil is my blood.

 

[pontiac428]

That's the best reason out there to do anything, especially if frivolous.