How many T-Slots on a Rotary Table, 3,4,6?

[SkarvenParticipant @skarven]

[SkarvenParticipant @skarven]

I’m traveling to London for the Model Engineer Exhibition at Sandown Park and I also want to do a little shopping while in England. A 3-axis DRO for my mill (I have a 2-axis), a 6″ rotary table and a few other things.

 

I’m probably a square kind of guy , because I, for no particular reason, think that 4 T-slots looks better on a rotary table than 3 or 6. I have never used one, so I’m asking: What is the best configuration?

 

Should I buy the dividing set at once, or is this a might never get used thing or something you can easily make yourself .

[JasonBModerator @jasonb]

four would be about right in a 6″ RT. on the smaller ones you tend to get three and then as the diameter goes up there is room for more slots.

 

I bought the dividing set at the same time, really depends on what you are doing as to how often it gets used.

 

If you are thinking of picking up your DRO from the supplier that advertises in ME then order in advance as they don’t bring many scales/displays with them.

 

J

[Michael GilliganParticipant @michaelgilligan61133]

I agree that four slots look better than three, and also I believe four to be more practical.

My BCA mk III mill has a built-in 8″ rotary table with four slots, and this is very satisfactory. … Except on a very small table diameter, you would probably find the distance between three slots excessive.

It is also worth making adapter plates with linear tee-slots and/ or an array of tapped holes. … I have one drilled to accept a 4″ diameter four jaw chuck, which is very useful for small jobs.

MichaelG.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, my 6″ Vertex RT only has three, and is very often annoying, I agree with Jason and think four is more appropriate. Also as Jason says, it does depend on what work you are doing as to how often it will get used, but you may find that you have more uses for the dividing set than you might think, I have with my set, its just a question of your own budget.

 

Regards Nick.

[JasonBModerator @jasonb]

Four also makes it easier to do this

 

J

[Gray62Participant @gray62]

Four slots are defintely better than three on anything of 6inch or greater RT, my 6inch has 3 and it is a real pain at times, the 12inch has four and gets a lot more use!

As far as dividing sets go, if you intend doing a lot of gear cutting or work requiring precision division, then get the set with the table. That said, I have just completed a DivisionMaster kit from MEDW and am in the process of fitting a RT with a stepper. For the amount of gear cutting I have ahead of me, (2 sets of gears for 2 traction engines) I am sure this will make life a lot easier and will reduce the brain strain!!

[Sub MandrelParticipant @submandrel]

I haven’t go any on my rotary table; I just made it the same as my lathe mandrel – so I can fit a chuck or my faceplate which has the best of both worlds with 6 slots..

 

Neil

[SkarvenParticipant @skarven]

Hi, and thank you for all the input.

It seems that 4 it will have to be! Being an old artillery guy, It seems logical to divide things into horizontal and vertical.

 

JasonB:

I ordered the 3-axis Mill DRO a week ago. I must say, that I originally bought the 2-axis mill against the recommendations of this forum, that said ‘3-axis’. The price for that special offer though, was so low, that even buying the 3-axis system afterwards, was cheaper than buying it then. After that I have been missing the ‘Z’.

I have now also bought an aditional ‘z’ measurement for the quill movement.

 

I also have a spare 2-axis mill system, Does anybody in the vicinity of London want it (It’s without the scales, so it’s not worth much , if you do not have them).

I’ll be in London from 8-13th December.

[Ramon WilsonParticipant @ramonwilson3]

Hi Skarven,

 

What ever version you decide on I would take a good look at the table itself to see if you can modify it to fit adjustable rotary stops at some stage.

 

My R/T is in constant use and I used to use the ubiquitous felt tip pen marks to work to but now having fitted stops can’t imagine being without them. They make repetitive angular moves a doddle without the constant worry of over shooting or turning the handle the wrong way as you start .

 

My table was a MES home built, the table itself fortunately having sufficient material to allow a tee slot to be cut into the periphery. I see some tables have a slot cut in for the table clamp – perhaps this can be used either by tee slotting or making expanding stops to grip into the slot.

 

Hope this is food for thought

 

Enjoy the show

 

Regards – Ramon

[SkarvenParticipant @skarven]

Posted by Ramon Wilson on 06/12/2011 20:08:44:

Hi Skarven,

 

What ever version you decide on I would take a good look at the table itself to see if you can modify it to fit adjustable rotary stops at some stage.

 

My R/T is in constant use and I used to use the ubiquitous felt tip pen marks to work to but now having fitted stops can’t imagine being without them. They make repetitive angular moves a doddle without the constant worry of over shooting or turning the handle the wrong way as you start .

 

My table was a MES home built, the table itself fortunately having sufficient material to allow a tee slot to be cut into the periphery. I see some tables have a slot cut in for the table clamp – perhaps this can be used either by tee slotting or making expanding stops to grip into the slot.

 

Hope this is food for thought

 

Enjoy the show

 

Regards – Ramon

I realize the stops will make some machining easier, but why are there no commercially available rotary tables with this feature. It is the same situation with my lathe. It is supposed to be ‘high quality …”, but why are there no stops for the feeds in X and Y.

 

What are the dimensions of your tee-slot on the periphery of the table?

 

And I will enjoy the show, The Model Engineering Exhibition is like nothing you can see in Norway.

 

Regards.

[WALLACEParticipant @wallace]

Ever thought of a slot arrangement like Harold Hall’s faceplate ?

 

 

I’ve never tried it but it looks a lot more ‘user friendly’ than the standard radial slots which never seem to be in the right place for the vice I want to use !

 

W.

Edited By WALLACE on 06/12/2011 21:03:20

[Ramon WilsonParticipant @ramonwilson3]

Hi Skarven,

 

I agree – you would think this would be a feature on R/T’s as it is so useful. I have fitted an adjustable dead stop for the saddle on my lathe but never felt the need for the crosslide.

 

Here is a pic of my R/T that I took for the Racer article. The original slots were cast into the top and as such were rather rough. I milled them out which made them proportionally a little large.

 

 

I’m indoors now but from memory the proportions of the slot are approximately 8mm wide gap, 10mm deep with 4mm steps. The tee nuts are curved to match the radius of the tee slot as are the stop blocks. The ends of the stop blocks are drilled and tapped for a 4mm screw for fine adjustment if required. The sub plate on top fits the 1.00inch bore in the top and the recess in the plate is for a removable boss that locates a Myford chuck.

 

Hope that gives you some idea of what to consider.

 

Regards – Ramon

[chris stephensParticipant @chrisstephens63393]

Go for four every time, the benefit is that you can bolt a four jaw independent chuck straight on. It is such a faff to fit a 3jaw SC chuck because it needs an adaptor.

chriStephens

[Francois MeunierParticipant @francoismeunier96697]

Hi,

with three slots you can mount the three jaw chuck directly without intermediate plate if height under the tool is a problem on a small mill as mine (a X2),

[chris stephensParticipant @chrisstephens63393]

Believe me, it is easier with 4Jaw as you can bolt through the body. Your hold down bolts look a teeny bit awkward to tighten.

I admit I am prejudiced as I hardly ever use a 3Jaw SC chuck, 4 jaw is more accurate and grips better, even on the lathe.

chriStephens

[John Stevenson 1Participant @johnstevenson1]

Best of both worlds, use 6 slots.

 

Four at 90 degrees to one another and the other two slot at 120 to one of the existing slots.

 

This way you get to hold 4 bolts items and 3 bolt items.

 

John S.

[SpringbokParticipant @springbok]

Do yourself a favour do not know what mill you have but a minimum of 4 slots and a MT2 centre then you will be able to make all these nice round items without buttons etc;

bob

[Sub MandrelParticipant @submandrel]

This is my ‘interesting’ home made setup…

 

The tailstock was literally a 10-minute job. What you may not see is that the chuck is on a 80mm diameter flange, behind which is a groove about 20mm swide and deep enough to fit 6mm nuts on chucks/faceplate then another flange which bears against the face of the base. The spindle runs through the plain body (CI in CI) to a brass 60-tooth wheel.

 

The fit of the spindle in the base is probably the best I have ever managed, much aided by the beautiful quality of CES meehanite. Cost was marghinally less than their rotary table castings but I think the end result is more flexible given my kit.

 

I missed a trick as I bored it to big of MT2 as it was before I had an MT2 reamer. If I ever get an MT3 reamer, I might put such a taper in the centre.

 

Neil

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