Rotary table securement

[Janderso]

The coax unit is a must have in my book.
Easy to use and you get a quick accurate centerline. Imho

 

[ChazzC]

The coax unit is a must have in my book.
Easy to use and you get a quick accurate centerline. Imho

Yes; the only disadvantage is that its use is limited on the vertically challenged mini mill: I can use it on the rotary table itself or something that is just above the surface of the vise, but would be hard pressed to use it on anything much taller.

 

[Janderso]

Yes; the only disadvantage is that its use is limited on the vertically challenged mini mill: I can use it on the rotary table itself or something that is just above the surface of the vise, but would be hard pressed to use it on anything much taller.

That is a good point. They do take up some real estate

 

[Parlo]

This is the shortest setup I've seen -

 

[Parlo]

I use one of these types for locating work edges: https://www.amazon.com/edge-finder/s?k=edge+finder I have demonstrated to my self that I can repeatedly locate an edge to to .0001". To center the RT, I use the same procedure that I use to locate the center of a cylindrical boss on the mill, namely, find left side of the boss, zero x axis, find the right side of the boss and hit 1/2 function key to set x axis zero at center of cylinder. Then I repeat for y axis. This procedure totally eliminates any runout and backlash issues.

You must have a very accurate hobby mill to find a position within a tenth. The play in the X & Y dovetails are more than a few tenths to allow for free movement, without accounting for free play in the Z axis or the squareness of the axes to each other.

Jig borers often have a vee + a flat surface so the table mass locates in the vee without any play, just like surface grinders, they have no gibs to adjust.
SIP jig borers even have the two axes separate, one on the bed and one on a gantry to achieve sub tenth tolerances, they are also very substantial castings.

 

[RJSakowski]

When I use my edge finder, I like to know that I have accurately located the edge so I will repeat three times. If I get the same position to the resolution of my DRO, I consider it accurate. While edge finders are a great solution to locating an edge, they aren't foolptoof. I fyou come in too fast with the top not centered, you can get a premature kick out. You can also overshoot so the only way that I am confident that the location is accurate is the repeatability of my position readout to the resolution of my DRO. The effort requires little extra time; usually the full operation is dine in less than a minute.

Aside from that, every error along the way contributes to the total error. As a practice, I strive to minimize the errors in each step. So far, it has served me well.

 

[Gandi]

Is this the proper way to secure the base of an RT to the mill table?
Looks about the only way to me.
Hope to figure out a way to cut a radius on corners of some flat parts.

Thank you for this. I am looking into getting roter table and was wondering how to secure it properly.
Now thanks to your thread I've gotten some very good advice.