# Show me your Rotary Table hold down fixtures



## Janderso (Mar 1, 2021)

I am really struggling with my rotary table.
Centering it on the mill spindle is easy, it's holding parts exactly where I want them that interests me.
I have some shop tooling I need to make to help me in this endeavor, I would love to see what you have done.
Thank you


----------



## Rootpass (Mar 1, 2021)

https://youtube.com/playlist?list=PL4wikbEbcE3Ko9ievzRws04nbqRfyBDZ1
		


He has many other videos that have been very helpful to me.


----------



## phubbman (Mar 1, 2021)

I made an adapter so that i can easily mount my lathe chucks centered on the rotary table.  This allows me to move work pieces from the lathe to the mill and back without having to remove them from the chuck.  It saves time and improves accuracy.  

I know a lathe chuck only holds some of the work pieces you'd want mounted to a rotary table, but maybe this approach will help with your current task.


----------



## JRaut (Mar 1, 2021)

phubbman said:


> I made an adapter so that i can easily mount my lathe chucks centered on the rotary table.  This allows me to move work pieces from the lathe to the mill and back without having to remove them from the chuck.  It saves time and improves accuracy.


This is exactly what I did.

In my case:   MT4 -- to -- 1.5" x 8tpi


----------



## Grendel (Mar 1, 2021)

Yes same here, just a short stub of aluminium, that centres the 4 jaw chuck in the rotary table, then screws and t nuts round the edges, to hold the rotary table to the mill, i used the 2 threaded holes to fix some bar that slides into the t slot on the mill, this extends out the back so it can be used when the chuck is vertical. then i can clamp the whole to the mill using machinist clamps into the t slots 2 at the front, and one at the back onto the top of the bar I added, for the chuck in a horizontal orientation.


----------



## Larry$ (Mar 1, 2021)

I have an 8" RT and always found I didn't have enough room on it to clamp the work. I cast an 11" plate and machined 8 Tee slots into it. I can also put my 8" 3 jaw on the table. Joe Pie's setups are helpful. It always takes me longer than it should to get set up.


----------



## Janderso (Mar 1, 2021)

Grendel said:


> Yes same here, just a short stub of aluminium, that centres the 4 jaw chuck in the rotary table, then screws and t nuts round the edges, to hold the rotary table to the mill, i used the 2 threaded holes to fix some bar that slides into the t slot on the mill, this extends out the back so it can be used when the chuck is vertical. then i can clamp the whole to the mill using machinist clamps into the t slots 2 at the front, and one at the back onto the top of the bar I added, for the chuck in a horizontal orientation.


Grendel,
You just gave me an idea, I'm trying to have the T-slots in the RT run perpendicular with the X axis. When I do this, I lose my mounting surface. By adding a long t shaped device with a step that runs off set of the t slot in the table.......
I'm not explaining this well.
My fixture plate never has the pre-drilled tapped holes in the right place. I guess it's normal to have to drill and tap new holes for every single thing you try to mount?
Frustrating.
A chuck would be very handy


----------



## Janderso (Mar 1, 2021)

Larry$ said:


> It always takes me longer than it should to get set up.


BOY howdy


----------



## Awround (Mar 1, 2021)

Here is a photo of the chuck adapter I use.  MT to 1.5 x 8.  Fitting on the left is used as a drawbar to seat the MT.




Cheers,

Adrian


----------



## RJSakowski (Mar 1, 2021)

My 12" Enco RT has a 1" diameter cylindrical hole.  I made an adapter with one end threaded for 1-10 tpi to fit the chucks from my Craftsman 6 x 18 lathe.  The adapter is internally threaded for 3/8-16 so I can use one of my clamp studs and a retention disk on the back side of the RT to fix the chuck to the RT table.  

For larger work, I will center the RT on the mill spindle and zero my DRO.  For there, I can offset my table to locate features on the work piece, using a pin or edge finder, depending on the accuracy required.


----------



## projectnut (Mar 1, 2021)

My rotary table is a bit different than most. Rather than a single set of T slots that intersect at the center of the table mine has 2 sets in one direction and a single set at 90*.  So far everything I've used it for can either be clamped to the table using standard milling machine clamps, or held in the 10" 4 jaw chuck.

Here's a picture of the table before it was cleaned up.


----------



## DavidR8 (Mar 1, 2021)

Awround said:


> Here is a photo of the chuck adapter I use.  MT to 1.5 x 8.  Fitting on the left is used as a drawbar to seat the MT.
> 
> View attachment 357580
> 
> ...


Thanks for this photo Adrian, I was struggling to picture how to attach a chuck for a threaded spindle without taking it off the backplate.


----------



## Janderso (Mar 1, 2021)

RJSakowski said:


> For larger work, I will center the RT on the mill spindle and zero my DRO. For there, I can offset my table to locate features on the work piece, using a pin or edge finder, depending on the accuracy required.


I guess what I'm missing is the part position relative to the spindle center=rotary table center.
I know I don't touch the table (other than the offset) once the RT is centered.
I am struggling with finding center of a part prior to the offset.
The part needs to be on center and the only way I know how to do that is the DRO and an edge finder.
I can't use the tools when I can't move the table.
I'm missing something simple here.


----------



## Grendel (Mar 1, 2021)

Here we go, you can see the two little bars I added to the two threaded holes, but of course any shape would work


----------



## mickri (Mar 1, 2021)

If you are using a 4 jaw chuck put the chuck on the lathe and center the part.  Then move the chuck to the RT.  Or with the 4 jaw chuck on the RT set up a DI and spin the RT to center the part just like you would on the lathe.  If it is an odd shaped part that you have mounted on the RT pick whatever edge(s) you want to reference off of and move the part until it is centered on the RT.  You will have to be creative in figuring out how to move the part.

I don't have a RT.  I use the swivel base that came with my vice and made a backing plate that fits my chucks.  It works for milling things at an angle and doing precise bolt circles.


----------



## RJSakowski (Mar 1, 2021)

When I use the RT, I will zero the DRO on the central axis of the RT.  I do so either by using an edge finder in the RT socket o mount a piece of material in the mounted chuck and cut a cylinder with an end mill by rotating the RT table and centering that cylinder with the edge finder.  With the mill spindle now referenced to the RT, I can move my table for various offsets.  If I wanted to align a workpiece with the x axis of the mill,I would set the RT at 0º and move to my desired position and use whatever method was acceptable to locate the feature.

The actual operations vary depending on what my starting workpiece is  I need to accomplish.  Usually, I will start with the RT as a first op setup so only a rough alignment of the workpiece is required. A square from the base of the RT will usually meet that requirement.  

Alignment becomes more difficult if you are trying to position a pre-existing part. If you are trying to machine a circular feature, you would want the center of the arc to be at the center of the RT.  I would center drill the center of the arc so I could use an edge finder  or test indicator to center tha part.   Then I would probably clamp the part and move the table to locate a secondary feature.  I probably would bother with trying to set the RT angle but simply record the angle and use it for calculating an offset (it would be nice if it were possible to set the RT scale to zero).


----------



## Flyinfool (Mar 1, 2021)

I am not sure how to explain this but I will try.

First I set the RT to exactly zero degrees and locked it in position.
then I got my RT setup on the mill with the T slots square to the table.
I then mounted a piece of scrap steel to the table and milled both sides square so that I know it is exactly square to everything else.
Now I flipped the RT upside down, clamped that bar into the mill vice, and drilled & reamed 2 holes for dowel pins.

I took a lot of time with each of these steps to make them as accurate as I possibly can.

Now whenever I put the RT on the mill and bump those 2 pins against the side of a T slot, I know that with the RT set for 0° the RT T-slots are parallel to the mill T slots.

When putting parts on the RT I can now square them to slots and know they are square.

I still need to set up a 3 and a 4 jaw chuck for the RT.


----------



## Janderso (Mar 1, 2021)

Flyinfool said:


> I am not sure how to explain this but I will try.


I think you explained the process quite well. I can understand it.
Now I can see why some make the pallet square. Easier to align parts to the Y-X axis and easy clamping.
This is just a fiddly business.

Flipping the rotary table =80 lbs. will be tricky.


----------



## davidpbest (Mar 2, 2021)

i'm not sure if this is totally responsive to your question, but _*here is what I have done*_ to help things a bit. I also use the gizmo Joe Pie made (referenced in a video in a prior post in this thread) for doing some alignment, and I have made a fixture similar to what Flyinfool described with precision dowel pins for situations where I'm not using a chuck on the RT.


----------



## Janderso (Mar 2, 2021)

Thank you David.
That sure makes things quick and easy.


----------



## cathead (Mar 3, 2021)

It's a home made set with 5/16 inch threading.


----------



## projectnut (Mar 3, 2021)

One thing I had forgotten is that i made a number of quick and dirty T bolts for my rotary table out of grade 2 carriage bolts.  I have 3/8" and 5/8" T nuts and clamping kits, but the slots in the rotary table are 1/2".   I put a 1/2" carriage bolt in a collet on the lathe, turned the OD of the head to 11/16" and faced off the top of the crown so it would slide in the slot.  The 1/2" square under the head locates the bolt so it doesn't turn when a nut is tightened on a standard milling machine clamp.

It's a little difficult to tell from the picture, but the rods sticking through the clamps in the first post of the thread "How Many Graduations are Necessary or Practical" are actually upside down carriage bolts.  The nice thing is they only take a minute or so to modify and come in all the standard diameters and lengths that are common for T slots.








						How Many Graduations are Necessary or Practical
					

A some might already know I've been working on a HSS lathe tool sharpening fixture on and off for a while.  I'm to the point I've started putting degree graduations on the table.  I have hard stops at each 5 degree and 10 degree mark, but was wondering how useful or practical it would be to...




					www.hobby-machinist.com


----------



## mickri (Mar 3, 2021)

One other thing you need to do with carriage bolts is remove the angle from the square.  It was pointed out to me by another forum member (I forget who) that the angled squares can damage the slots.  I use modified carriage bolts in all of my T slots.


----------



## metric_taper (Mar 4, 2021)

Here is my 6" RT and 12" RT. I made a plate from 3/4" hot rolled, that I rough cut with an OA torch, then mounted in a 3 jaw and got a pilot round so I could flip them and do the rest of the lathe work. I used the RT to drill any of the bolt circle holes needed to mount the chuck from the back side of this plate, as well the top side hex head cap screws. Then it was a matter of bolting the assembly down on the mill and use an indicator to get the chuck body concentric to the RT.


----------



## Dabbler (Mar 5, 2021)

thanks @davidpbest that was a great video!

I made a 2024 aluminum plate, 12" square for my 6" rotary table.  I use it as an _expendable  _set up plate, drilling holes as I need them.  I milled slots and keys for precise alignment.


----------



## metric_taper (Mar 5, 2021)

metric_taper said:


> Here is my 6" RT and 12" RT. I made a plate from 3/4" hot rolled, that I rough cut with an OA torch, then mounted in a 3 jaw and got a pilot round so I could flip them and do the rest of the lathe work. I used the RT to drill any of the bolt circle holes needed to mount the chuck from the back side of this plate, as well the top side hex head cap screws. Then it was a matter of bolting the assembly down on the mill and use an indicator to get the chuck body concentric to the RT.


OK, After seeing post #25, Dabbler's post, I think I understand the OP's question, a mounting plate for the RT to the mill table.
I put my 6" on a riser plate as the crank interfered with the table top, so I moved my RT from the storage shelf to the mill and took some photos.
The table also came with index hole plates, which I've never used. But I don't think my riser plate is thick enough for them to clear. So if the OP is still about, keep that in mind.


----------



## NC Rick (Mar 5, 2021)

For what it's worth, I was getting ready to pull off my chuck from the table to hold a rectangular part.  This piece of 4.5" bar from the bin.  I drilled a radial pattern of 3/8" 16 tapped holes.  Some of the others were in there and they proved to be helpful.  It's a simple idea I'm guessing many have had but it was enlightening to me. 


Less thick would be fine.  I may make a bigger one at some point.
I got the idea from this lathe fixture I started on with 7.5" disk.  If I only had another... 


maybe this will give someone else an idea.  I think it will save me time.


----------



## 9t8z28 (Mar 6, 2021)

I hope I understood your question but Fixtures for Rotary tables are always challenging.  I find that the mitee-bite style eccentric or wedge workholding type work very well because they take up little space.  One thing I have done is make a bunch of Long T-nuts with many different-sized tapped holes.  I also found that simple 2 piece vises work well because they can be placed anywhere on the table.  I have made a lot of one-off toe clamps to hold work and they were usually made specifically for each job.


----------



## jmarkwolf (Mar 7, 2021)

A few years ago I spotted this hardened and drilled/tapped round fixture plate in the local Craigslist. Didn't have a particular use for it, wasn't even sure what it was for, but for $20 I couldn't pass it up. 

A year or so later I bought the 10in rotary table you see here for my mill. Lo and behold the round fixture plate fits the rotary table perfectly! 

Now I have a number of ways to clamp to my rotary table: 1. using the t-slots, 2. Using a 8in lathe chuck, and 3. using the round fixture plate.  Now if I only had more RT projects.


----------



## firemaker76 (Oct 1, 2021)

phubbman said:


> I made an adapter so that i can easily mount my lathe chucks centered on the rotary table.  This allows me to move work pieces from the lathe to the mill and back without having to remove them from the chuck.  It saves time and improves accuracy.
> 
> I know a lathe chuck only holds some of the work pieces you'd want mounted to a rotary table, but maybe this approach will help with your current task.


I've been pondering this myself, and this sounds like the exact solution that I need.  Thanks for sharing guys!


----------

