Tool Rotary table fixture plate

[CWret]

I started to make a fixture plate for my 8” RT last year but finally (hurried up and) got it done in time to take it to the Ontario meetup. It generated some interest so I decided to show it here too.
These are an easy and inexpensive build that greatly increases the capacity of your RT and is significantly easier to manage (lighter) than a monster 12” RT (T slots would be nice in a fixture plate but this design is much easier and lighter).
It is 13.5” diameter because thats the largest circle I could cut from the old (rusty) piece of 5/8” plate that I had kicking around.

It was cut with the plasma cutter:

The plate is attached (bolted) to the RT via its T slots:

It is intended that one side of the new fixture plate will not be cut or damaged but the surface of the reverse side will be considered sacrificial.
In the next picture the blue arrows are pointing out the attachment bolt recesses when this side is up. The red arrows are pointing to the attachment bolt holes when the reverse side is being used (these holes have recesses on the other side).


In the next picture the blue arrows are modified MT2 adapters that fit the centre RT hole. The adapters were milled to match the hole diameter in the fixture plate. It’s a tight fit, with less than 0.001” clearance and it needs to be wiggled and tapped to get the plate on or off (yes i did mill the adapter diameters because that’s what you do if you don’t have a lathe). Also in this pic - the red arrow is an attachment bolt in the RT T slot. The green arrow points out a pair of 1/8” dia springs, which along with the 1/8” dia pin (yellow arrow) are inserted into the 1/8” hole that is centred in the top of the MT2 adapter. The protruding tip of the pin makes it easy to center a part as long as you don’t mind giving the part a center punch mark.

Here’s another look at the locating pin:




I milled a pair of angle brackets that can be bolted to the fixture plate. This gives a solid stop or pair of stops to help locate a part (or multiple parts) in the same location. On the outer ring of holes the two holes in the bracket line up with the 1st and 5th ring holes. Similarly these bracket holes also line up with the 1st and 7th hole in the second ring of fixture plate holes.

In above pic the machinist square shows that the brackets are at 90 degrees and are attached to the outer ring of holes. In the next pic I added some Prussian Blue grease to the brackets for improved visibility and replaced the machinist square with a plastic drafting triangle (green masking tape on the triangles for better visibility).

Note that in above pic the horizontal bracket is attached to the outer ring of holes and the vertical bracket is attached to the second ring.
The extra hole in the bracket works for the third ring of holes as seen here:



The angle between brackets can be set at 30, 45, 60, 90, or 120 degrees. Here’s some examples:

 

[Susquatch]

Someday, my 10" rotary table will become a 14" this way. I especially like the reduction in handling weight that results from a 2 part design (10" table + 14" plate).

I'm not at all concerned about the lack of T-Slots. Threaded holes are more than enough to satisfy my needs.

Just need to locate a nice big piece of plate.

Well done @CWret.

 

[Tecnico]

Taking notes for a potential future RT…….

D

 

[DavidR8]

Me thinks I see a use for the chunk of 1/2” plate that I’ve been moving around.

 

[Susquatch]

Me thinks I see a use for the chunk of 1/2” plate that I’ve been moving around.

Exactly why one should never pitch things that might come in handy some day. Another vote for hoarding stock.

 

[DavidR8]

Exactly why one should never pitch things that might come in handy some day. Another vote for hoarding stock.

View attachment 47341

I just need better hoarding management!

 

[140mower]

Exactly why one should never pitch things that might come in handy some day. Another vote for hoarding stock.

View attachment 47341

.....not hoarding, prudent protection......

 

[YotaBota]

I read a thread some where that a disc brake attached to the RT makes a good platform for larger items. Discs use 4 and 6 bolt do easy to match up to the 4 or 3 slot tables.

 

[Susquatch]

I read a thread some where that a disc brake attached to the RT makes a good platform for larger items. Discs use 4 and 6 bolt do easy to match up to the 4 or 3 slot tables.

I use a brake disk for Tramming. Allows me to keep my mill vise in place at the same time as I tram.

But I can't really imagine it extending a Rotary Table very well. It has a big open center.

Got any photos of how that would work?

 

[Doggggboy]

I bought my mill from John Conroy and I think he mentioned that he had built a rotary table using a brake disk.
John?

 

[John Conroy]

I like using brake rotors as they provide a precisely machined and relatively cheap chunk of cast iron that can be adapted for lots of uses. I built a small simple indexing table using an 11.5" brake rotor, a 5" 3 jaw chuck and a hub/bearing assembly from a GM SUV.



I bolt it to a 9" angle plate to use it vertically or lay it flat for horizontal use.





It has a positive locating pin to index every 10 degrees or can index to any angle and be locked by 3 opposing brass tipped grub screws. I still use it quite a bit as it is light enough to move without the risk of a hernia. That is not the case with my Vertex Super Spacer which weighs 175 pounds with the 8" chuck bolted on. The trouble with the Super Spacer is that it only came with the chuck, no table/fixture plate. I made a rotary table and fixture plate from a 12" GM truck brake rotor and a 12" round piece of 1/2" thick scrap plate steel. I machined the center out of the rotor so it will fit over the locating register for the chuck on the Super Spacer and bolt on using the same 3 bolt holes that hold the chuck in place.



I had to machine some material off 1 side of the rotor to clear the body of the SS.



I mounted the rotor into the SS chuck and used a 1/4" end mill to hog out the center of the mounting flange for a nice slip fit onto the register.

















The fixture plate is bolted to the rotor with six countersunk SHCScrews and was ground flat on my lathe with a tool post grinder. It is positively located with two 6mm dowel pins.

 

[historicalarms]

.....not hoarding, prudent protection......

My problem is the deep grass "protects" better than my "remember where its at" function.

Good job with the rotors John, I have half a dozen in that long grass waiting for their # to come up in the "project" list.
those big ol' break drums that Chicken will laying around make excellent grinder stand bases....heavy as hell and wont tip easily

 

[YotaBota]

Great job John.

The disc use I'm thinking of was to allow a 6" table to hold larger diameter pieces. Mount the disc to the RT using the existing disc bolt holes and go from there. Mounting the disc to a self centering adaptor plate would make the install quick and easy.

 

[Susquatch]

I bought my mill from John Conroy and I think he mentioned that he had built a rotary table using a brake disk.
John?

I see. Very clever @John Conroy !

@Doggggboy - John removed that center hub that I thought would be in the way and also used the wheel hub.

I certainly agree with John that Brake Disks make great stock for numerous projects. They are really cheap especially when you consider that they are typically ground to under a tenth runout. Hence my reason for choosing to use a brake disk rotor for my Tramming fixture. ( There were other reasons too, but without the grinding precision they would not have mattered. )

I didn't want to remove the center hub mount for my application, but in hind sight it would have been easier than making 3 ground blocks to clear the vise. The only concern would have been releasing residual stresses and introducing new machining stresses. But they are likely minor.