Rotary table securement

[finsruskw]

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.

 

[Chewy]

I did something like that in the beginning. I made a set of dedicated hold downs to mount in vertical and horizontal position. The deciding factor is that it holds the RT securely without moving against milling stress and without causing any damage to the mill table, Make sure the RT is secured at another place to prevent rotation. Mine is at opposite end.

 

[finsruskw]

Same here, on the other end as well
It's Phase II table I picked up earlier this year and have just now got around to trying to do something with it.

I should be good to go now I guess.
Time to get it trammed in now.

 

[woodchucker]

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.

yes, it's acceptable.
I have done the same. The problem with a screw/nut is the nut does not have enough space to fully fit into the recess 3/8 - 16 so I do that pretty much as well.

 

[Chewy]

Check with Jo Pi on his RT tramming video. Most common way is to dial in the center hole, He does the RT spinning on the arbor. I tried it and he is right. I am making a special adapter for the RT to do this. A mag base and indicator is a PIA to set up but shows how far off you really are,

 

[finsruskw]

Well, I guess I'll either have to remove the vise or move it over as I do not have enough travel on the X axis to center the quill over the hole.
I could squeeze by if I used one of the vise hold down holes for the base end of the RT.
It would be close 1/4's though.
Always something

Most common way is to dial in the center hole, He does the RT spinning on the arbor. I tried it and he is right.

Can you expound on this?
I must be dense or something this AM!!

 

[Chewy]

I was afraid you would ask that. Luckily he does it quite often. He did a whole video on the setup and how he does it, but I can't find it. It takes into acount slop in the RT. Here is a snapshot of the setup in a current video. Go to about 11 minutes to see a quick view. About 10 seconds. Unfortunately he is using a very old General mag base that is no longer available. I am making an adapter to bolt into the tee slot and hold a dedicated DTI to the spindle. By raising the spindle up, I can use it on the end mill. It does make a difference by a couple of thousands.

 

[Parlo]

I was afraid you would ask that. Luckily he does it quite often. He did a whole video on the setup and how he does it, but I can't find it. It takes into acount slop in the RT. Here is a snapshot of the setup in a current video. Go to about 11 minutes to see a quick view. About 10 seconds. Unfortunately he is using a very old General mag base that is no longer available. I am making an adapter to bolt into the tee slot and hold a dedicated DTI to the spindle. By raising the spindle up, I can use it on the end mill. It does make a difference by a couple of thousands.

Does that mean the if the centre hole was trammed it would be a couple of thousandths out to the RT bearing?

 

[Chewy]

It has been .001-.0015 off when I did it. In most cases it doesn't mean anything, but I do it to get better results. Allows me more wiggle room to have something else out a little bit and still hit my target. Do a couple of trial runs and see if it is worth it. I consistently end up with better then .002 tolerances on my work. That allows for better fitting and match ups. In production runs, tighter tolerances means higher cost. I'm not in production and doing extra steps like this only take about 5 minutes. And it is practice for the times you need to hit 1/2 thous precision. When I finish the adapter, it won't even take 5 minutes.

 

[Parlo]

It has been .001-.0015 off when I did it. In most cases it doesn't mean anything, but I do it to get better results. Allows me more wiggle room to have something else out a little bit and still hit my target. Do a couple of trial runs and see if it is worth it. I consistently end up with better then .002 tolerances on my work. That allows for better fitting and match ups. In production runs, tighter tolerances means higher cost. I'm not in production and doing extra steps like this only take about 5 minutes. And it is practice for the times you need to hit 1/2 thous precision. When I finish the adapter, it won't even take 5 minutes.

Thanks Chewy.
The centre hole is made concentric to within tenths when new, so you are averaging out the play in your table. If you had an indicator stylus in the hole can you push the table about and see the indicator moving? This would show any slop.