Centering the rotary table

[BRIAN]

I needed to set up the table on the mill for a quick job that had to be reasonably accurate
and I thought that if two centres are good enough to determine lathe accuracy they may well do the job on the mill
I am probably not the first to try this but it's worth a mention.


It worked perfectly for me, the centres can also be tested for accuracy by revolving the quill or table.

Brian.

 

[Bishop]

Looks like a slick solution to me, will have to give that a try.

Thanks
shawn

 

[mzayd3]

This is a technique that I adopted. It works really well.

 

[Knobley]

Thank you Brian. I like that idea. Never thought of it.

 

[zmotorsports]

That looks like it should work.

I use an idea I got from one of Tom Griffin's videos, a machined plug/adapter that tapers into the rotary table and the other end simply goes into a collet. Center it over ther RT until it slides easily in and out of the bore on the RT then lock the RT down. It is pretty quick and simple once you take some time to machine the adapter.

 

[RandyM]

This is a technique that I adopted. It works really well.

That looks like it should work.

I use an idea I got from one of Tom Griffin's videos, a machined plug/adapter that tapers into the rotary table and the other end simply goes into a collet. Center it over ther RT until it slides easily in and out of the bore on the RT then lock the RT down. It is pretty quick and simple once you take some time to machine the adapter.

Instead of making the adapter I just use a center chucked in the spindle.

 

[Holescreek]

Forgive my ignorance, the setup is truely unique in that I've never seen anything like it before. How is this faster or more accurate than putting an indicator into the spindle and tramming the center hole? Won't you still have to do that before using the table?

 

[arvidj]

How is this faster or more accurate than putting an indicator into the spindle and tramming the center hole? Won't you still have to do that before using the table?

I don't have a great deal of experience in this area but will offer an opinion anyway.

I think you are correct that you 'should' measure it after you have used one of the short cuts ... the 'measure twice, cut once' mantra. But I think it allows you to get much closer to "right" the very first time you do measure it, possibly not having to change anything at all.

 

[zmotorsports]

I agree with confirming after setup. I like the motto of trust but verify. I trust my rotary table will be within a few thousands by using my adapter but then by throwing my test indicator on the quill and running it around the center hole I merely verified its accuracy or had to move it ever so slightly. It is still much faster than setting up by test indicator alone in my opinion.

I have heard friends tell me that they hardly use their rotary table or hate to remove their vise from the mill table because of the time it takes to set them back up and dial back in. I really don't understand that because after very little practice you can have a vise or rotary table dialed in rather quick. I have just found the little trick I use helps me get there a bit faster.

 

[Holescreek]

Again, I appologize for questioning a new (to me) method, but I get an occasional visitor to my shop that will wonder why I'm using an indicator to tram a rotary table in when all I gotta do is eyeball a steel rule for parallelism to the table.

I agree with confirming after setup. I like the motto of trust but verify. I trust my rotary table will be within a few thousands by using my adapter but then by throwing my test indicator on the quill and running it around the center hole I merely verified its accuracy or had to move it ever so slightly. It is still much faster than setting up by test indicator alone in my opinion.

I have heard friends tell me that they hardly use their rotary table or hate to remove their vise from the mill table because of the time it takes to set them back up and dial back in. I really don't understand that because after very little practice you can have a vise or rotary table dialed in rather quick. I have just found the little trick I use helps me get there a bit faster.

I'm out of time today but tomorrow I'll post some pics of the tricks I use to make setting the RT up very quick and accurate. The worst part is lifting it.