fitting a 4 jaw chuck to a rotary table

[Firebird]

Hi

I have a 4" rotary table, I also have an adapter, which fits into the central 2MT hole, which is threaded to take the Myford screw on chuck back plate. Its very good and means that work can be transferred from the lathe to the rotary table and back to the lathe without the workpiece ever leaving the chuck. There is one draw back with this system and that is the screw on chuck. On a few occasions the chuck has unscrewed during machining and ruined the job. Iv'e had this old 4 jaw independant chuck for years. It came with my first lathe and has been lying under the bench for I don't know how long so I dug it out today and with a bit of freeing oil got it apart and cleaned it up. My plan is to make an adapter plate to fit it to the rotary. I'm going to turn a short plug with a 2MT and a locating pin to line it up and make it quick change. I also have a different type of myford adapter which bolts onto a back plate that I will use.

Heres the bits so far. I have a bit of ally plate 3/4" thick that I will use. Steel would better but I don't have any that size at the moment. I'll post more when it progresses.





Cheers

Rich

[smfr]

This is something I could use too, so I'll be following. What brand of rotary table is that?

Simon

[Firebird]

Hi Simon

Its a Vertex

Cheers

Rich

[Jadecy]

There were some posts a while back from I think it was "DeerGuy" on several forums. He was making adapters to mount a D1-4 camlock backed chuck on a rotary table. I'm interested to see your solution. I need to do something similar soon so this thread is very timely for me! 

[Firebird]

Hi

A mention as to why I bought this particular table. At the time I had my Myford ML7 and had recently purchased an X1 milling machine. I bought the milling machine from the wrong company as it happens but thats another story. The X1 mill is a super little machine but does have its limitations, column height etc, so a 4" table was as big as I could go. Having looked at most of what was on offer and reading reviews I settled on this Vertex which has turned out to be a cracking rotary table. The main thing that swung it for me was the 2MT hole in the middle. Both the myford and X1 use 2MT tooling so a lot of what I already had would fit straight in. Its a bit awkward if say you fit a 2MT collet as you have to turn the table over to fit a draw bolt from underneath then fit the table to the mill then turn the table over again to release the collet. The same applies to any tooling that is fitted this way. The other thing that is sometimes awkward is the fact that it only has 3 T slots where most have 4 but the tables with 4 T slots don't have a 2MT in the middle. You takes your pick. Overall though it is a good table.

Also worth mentioning is I'm using a 4 jaw chuck that I already have. I can't see any makers mark on it.

Cheers

Rich

[smfr]

I bought a 4" Phase II with a MT2 center bore for the same reason; I already had MT2 tooling. It does, however, have four slots, but since clamping space is so tight, I think there's little to gain over 3 slots. I know what you mean about using collets in there! I got an MT2 ER32 collect chuck and use that to hold small parts; then you don't need to remove the table from the mill to change parts.

Simon

[Firebird]

Hi

Maybe your right about the slots Simon its just that I always seemed to need 2 slots opposite each other.

I managed an hour or so this morning so started on the central guide pin. It needs to have a 2MT taper machined first. Unfortunately I forgot to take photos of the set up but its fairly straight forward. I have a 2MT parrallel test bar so set that up between 2 centres, one in the mandrel and the other in the tail stock. With a dial guage clamped in the tool post I set the top slide over and repeatably wound the top slide back and forth along the 2MT section of test bar adjusting the top slide angle until I achieved a steady reading on the dial guage. You could of course use anything with a 2MT that can be held in centres as a test piece.

A piece of steel in the chuck was quickly turned. I have drilled and tapped the end 6mm.



Its a pretty good fit in the rotary table.



Here I am marking where it needs to be turned down to.



I have started maked a drw bar from some 8mm steel turned down to 6mm and threaded.





The plan now is to hold it in the lathe mandrel with the draw bar and very accurately turn a spigot to 1/2" and drill and tap this end also to 6mm. The idea is to bore a 1/2" hole in the new chuck back plate so that I can easily centre it on the rotary table. I'll post more as and when I get some more done.

Cheers

Rich

[Firebird]

Hi

Finished the draw bar. A scrap of ally knurled, drilled through then the two parts cross drilled together and a steel roll pin knocked in.



Fitted in the lathe.





Turned down to an accurate 1/2"





Then reversed in the lathe and held in a 1/2" collet to turn down to size.



In the rotary table, sitting nicely just below the surface.





I'm not sure yet what final length it needs to be, probably 5/8" the same thickness as the ally back plate. I will drill and tap it 6mm, don't know why yet but I'm sure it will be usefull for something.

Cheers

Rich

[Bogstandard]

Rich,

If you drill and tap the sticky up bit that locates inside the chuck and backplate, when the backplate is eventually bolted to the table and centred, you can use a screw in the end of the centreing spigot and pull it upwards, out of the RT and through the backplate and chuck.
This leaves a hole under the chuck and through the RT so that you can hold longer pieces in the chuck.

John

[Firebird]

Hi

Thats good thinking John, being able to get the alignment tool out would be a bonus but its just occurred to me that if I bore a 1/2" hole in the back plate that will fit onto the spigot I won't be able to pull it through as the 2MT bit is larger. I will have to make an accurate collar that fits onto the spigot and bore a bigger hole in the backplate, say 3/4".

Cheers

Rich

[Bluechip]

Rich

Not quite sure if this is relevant, but this is what I use. ( Vertex HV6, 4 slot. )

It's the 2MT end from a knacked drill bit, flutey bits and tang parted off, tapped and a bar screwed and Loctited in.

Fat bit just Loctited on. Poke into S7 mandrel socket and machine. Clocks about .0003" TIR. Good enough for me.

The 4" chuck is fitted to a plate, bored the same as the chuck throat.

So, R/T on mill and use Co-ax indicator on fat bit to centre. Lock axes ??

Then lower chuck onto R/T, line up 4 tee-nut cap screws, tighten chuck jaws onto fat bit and lock the screws down.

The fat bit is just below jaw tips, spacer on, slacken chuck off and wind a nut down the  threaded end. Out pops contraption.

Now have R/T centred on mill and chuck centred on R/T. Usually better than .002" TIR.

Takes about 3 mins.

Dave

 

[Bogstandard]

All I did Rich was to turn off some of the taper until it went through the backplate.

If I remember rightly, it was only about the top half inch that needed to be reduced.

John

[Firebird]

Hi


Dave, Thats a good tip using old 2MT drills, Iv'e got a couple of them somewhere. I take it that the 2MT end is soft?

John, I'll look into that to see how much I can turn off, might be the week end now though.

Cheers

Rich

[Firebird]

Hi

I have made a chuck key as I don't know what happened to the original. They are not that expensive to buy, about ?6.00 but I had the materials to hand and it took less than 1 hour. I'll show briefly how I did it, It may be of use to newcomers. Its easy to forget that something simple like a chuck key to us old hands may be a challenge to a newbie.

Turn a bit of 1/2" steel down to size, in this case I need a 1/4" square then swing the top slide over a bit and turn the tapered section. I then fitted it into my home made square collet block to machine the 4 sides.



drill and tap the end 4mm and then cross drill a 1/4"



Cut a shallow groove in the centre of a bit of 1/4" steel to make the handle.



Fit the handle into the body and secure with a grub screw.



Job done.


Please let me know if all that was of any interest or not. if its a bit too simple for my fellow members I'll stick to the point.

I have decided to fit a steel insert into the ally plate, it will wear better. I have made the hole large enough for the 2 MT guide to pass through.





I have centre punched the centre of the ally plate and drilled and tapped 2 holes 6mm to match the chuck mounting bolt positions. The ally plate is then fixed to the face plate with 2 6mm cap head bolts and washers. 2 washers as spacers between the ally plate and face plate. Here I am setting it up on centre with a dial guage and spring loaded pointer.



The centre is bored to suit the steel top hat sleeve, I have made sure it will be a good press fit. Then the chuck register is machined.



The 4 jaw chuck I am using is a rear bolt fixing, I need a front face fixing so the holes must be drilled through. The central hole through the chuck is 1" so a bit of 1" steel bar in the vise for it to turn round on and a clamp to hold it steady. The clamp has already been removed in this shot.



Then turn it over and countersink. Likewise I have already removed the clamp.



A 6mm countersunk cap head sits just below the surface.



A trial fit



Cheers

Rich

[zeeprogrammer]

Please let me know if all that was of any interest or not.

It's of interest. If nothing else it's a reminder that we can make nearly anything we need rather than buy it.
And as simple as it may be...that grub screw was a tip to more than one person.