# Small rotary table large project, help.



## uchytil (Apr 28, 2021)

So I have a 6" rotary table for my Smithy 1340.  I've been looking all over the place for ideas on how to do a job that will be 7" diameter.  I will be making brake backing plates from 3/4 6061 for old german motorcycles.  I need to know if anyone has pictures/plans/ideas how I can do this with my table.  Larger plate?


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## Lo-Fi (Apr 28, 2021)

You're probably going to have to give some more details on the types of ops you're intending to do?

Regardless, your biggest battle seems to be attaching the stock to the table without holes where you don't want them.... Some kind of fixture plate might not be the worst Idea.


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## Larry$ (Apr 28, 2021)

No matter what size RT you have, it will always be a bit small. I've got an 8", same problem. I cast an 11" aluminum disc, put 6 Tee slots in it and bolted it on. Works but takes more time to setup. I think you could just make a fixture plate. Drill & tap for the job at hand. Maybe a universal plate that you can use on the RT, vice  or mill table. I see another post beat me to the fixture plate idea.


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## JimDawson (Apr 28, 2021)

I added a 12 inch dia. plate to my 6'' RT to be able to work on some 28'' round pieces.  The process is in this thread.  https://www.hobby-machinist.com/thr...-weighing-counting-machine.90454/#post-821478


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## uchytil (Apr 29, 2021)

Thanks for the replies!  I'm going to be honest and say I have no idea (yet) how to make a fixture plate.  One thing is for sure.  The item I plan to make has a center hole where the axle goes through.  In fact the hole will be larger to accept a steel bushing.  Can items be held in the center hole of the rotary table?  I've never used one yet.  The plan is to center drill the 3/4 aluminum 7x7 plate.  then cut it 7" diameter.  Next is to cut an od shape on one side that holds brake components and finally cut the remaining stock down to 3/16" with and groove that matches the wheels drum.


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## Lo-Fi (Apr 29, 2021)

Holding by the centre hole is fine for drilling, not for milling. It's one of those things you'll get away with until you don't, then it's quite catastrophic!

By fixture plate, I mean some arrangement to hold or otherwise interface between the work and the table in such a way that allows access for the machining ops you want to carry out. A large flat plate with holes drilled strategically will probably do. You've picked quite a challenging project for first time with an RT, it has to be said!

When workholding on my RT I do often use the center hole, with at least two other points of clamping, moving clamps if needed for clearance. Order of operation is critical.


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## brino (Apr 29, 2021)

Larry$ said:


> No matter what size RT you have, it will always be a bit small.



........until you go to lift it....then it will feel too big!

-brino


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## Lo-Fi (Apr 29, 2021)

Just thought I'd add that there's a piece of Ali under that steel workpiece! This works really well as long as you're careful to set your cut depths accurately.


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## DavidR8 (Apr 29, 2021)

The sticker on @Lo-Fi's mill.


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## Suzuki4evr (Apr 29, 2021)

DavidR8 said:


> The sticker on @Lo-Fi's mill.


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## Lo-Fi (Apr 29, 2021)

Lol! I really ought to cover that up for forum pics, hadn't I


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## NC Rick (Apr 29, 2021)

Universal anti-liability instructions.  Less words are  always better.


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## Shotgun (Apr 29, 2021)

Lo-Fi said:


> Lol! I really ought to cover that up for forum pics, hadn't I


No.  You should tell us where we can buy a ream of them.


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## Lo-Fi (Apr 30, 2021)

Shotgun said:


> No.  You should tell us where we can buy a ream of them.








						WARNING Stickers MK. II - Etsy UK
					

*Stickers and Rulers are shipped separately. Please allow 4 weeks for the family sweat shop to make, package and ship your order*  4 stickers 3.75x5.25; 100mm x 130mm die cut high quality vinyl. 1 each of not to be operated by fuckwits, no dumb area, welding and this will hurt the whole time.




					www.etsy.com
				




Apologies for the thread derail!


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## mmcmdl (Apr 30, 2021)

I need to get a few pac.........................no , I need to buy them out !


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## uchytil (Apr 30, 2021)

Lo-Fi said:


> WARNING Stickers MK. II - Etsy UK
> 
> 
> *Stickers and Rulers are shipped separately. Please allow 4 weeks for the family sweat shop to make, package and ship your order*  4 stickers 3.75x5.25; 100mm x 130mm die cut high quality vinyl. 1 each of not to be operated by fuckwits, no dumb area, welding and this will hurt the whole time.
> ...


Nah, fun stuff!  And yeah the sticker would be something I'd have.  Thanks for being up front about using the center hole.  Ill need to make a plate larger than my job it seems and figure a way to hold it while milling a 7" circle and the odd shape for brake parts.


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## John281 (Apr 30, 2021)

I had the same issue in the past.  I bolted an old, 4-lug disc brake rotor onto my rotary table which expanded the usable area enough to get the job done.


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## uchytil (Apr 30, 2021)

John281 said:


> I had the same issue in the past.  I bolted an old, 4-lug disc brake rotor onto my rotary table which expanded the usable area enough to get the job done.


That's so funny.  I was in my shop thinking the same thing.  I have a few rotors off my wife's car and wondered if there was a way I could use them.


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## Lo-Fi (Apr 30, 2021)

Love it! Another way is to mount a large 4 jaw on the RT. This afternoons project... A piece of steam loco suspension that needs the top renewing:






I'll be making the replacement plate up on the RT too, it's horrid doing plates on the lathe and my lathe isn't big enough anyway!


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## NC Rick (Apr 30, 2021)

@Lo-Fi , that looks like a double riser block job for sure.  My little Bridgeport wouldn't have a chance!


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