# New adapater for my RT



## Blogwitch (Feb 5, 2015)

Here is a post about my interchangeable tooling upgrade, where I can swap between my lathe and the RT on my mill at will without having to move the piece part from the chuck. I have a nose converter for my lathe, which can change it from D1-4 to Myford thread, this is about the other half.

So this is what I am replacing this time, the 2MT adapter with a Myford nose on it.
These have kept me going for a while, but I am just not happy with some of the surface finishes I am getting due to lack of rigidity. I just don't like cleaning up machining marks.








This big blue lump is what I am going to make it out of. I was given a long length of this stuff, I have a feeling in the back of my mind that it is cast iron, but I am not sure. I think it is an end of day pour and everything left over got thrown in the pot. You can just see a light patch on the cut face. This is a counterbalance weight off a garage door and they just stuck a length of bent rod in the casting box to make a hanging loop, that is a bit of the steel rod.
But this doesn't have to withstand massive forces, so it will do.







The lump was mounted into the 3 jaw and I attacked the hard outer skin with a pair of roughing tools. The skin must have been around 1/16th of an inch thick, but once the tool got under it, it came away fairly easy. I am preparing the metal here for all the following machining operations. I have created a main datum bottom face and a perfectly square side to it.







The centre hole was then drilled and fine bored to accept a close tolerance fit of the MT locating spigot. The spigot had previously had a non tapered area machined on it. It is that close fitting machined end and this bored hole that will align the adapter perfectly central on the RT. So that is all the datums produced to close standards. Now I had to make sure that everything else was square to these datums.







Out came the soft jaw chuck.
I love working with soft jaws, because if they are used correctly, your accuracy and concentricity of parts takes a massive leap forwards, and for stuff larger than normal collet work, knocks four jaw working into the shadows, because it is so easy to do.







With the jaws tightened down onto a bit of stock bar, the jaws are gently bored until you can just fit your turned part into the made recess.
Once that stage is reached, the barstock is removed and every burr on the machined area is dressed down and inside the jaws are cleaned up spotless.







The datum faces can now be clamped up in the soft jaws, and gently bedded into the recess.
You can now work with confidence in the knowledge that anything you machine up outside the jaws will be perfectly square and concentric to the datum areas.
The part will not be removed from the chuck until every machining exercise is completed, except for the mounting holes.







The roughing tools were brought into action again, and they soon got rid of the tough outer skin and a lot of the bulk on the part.







Then everything was turned up in preparation for single point cutting the thread.







The threading and other size getting machining was carried out, then I bored down to meet the previously bored hole. but this time it was about 10 thou larger in diameter. I had drilled and tapped the end of the locating spigot, and by feeding a bolt down this hole, I can remove the spigot if I need to hold a bit of long rod in the chuck, this will allow me to hold a rod over 6" long down in the RT.







This shot shows the locating spigot in position and the new backplate with threaded nose.







This is how it will fit together.







The backplate just needs four holes drilling and I need to make up the t-nuts and bolts.  I got the holes in the adapter plate drilled by bodging together a holder and drilling them using the RT.
As you can see, the t-nuts are a rather weird shape, that is because with the disc being so small, I was working at the very inner limits of the slots. They hold just fine.
I marked up the adapter with a '0', this hole, if ever the plate is removed, will be put back in line with the '0' on the scale around the RT.







This is the side you very rarely see. But I noticed that the slots and holes were there if ever I wanted to put locating blocks onto the bottom. So why not?







So I got my aligning blocks off the mill, and they fitted perfectly in the slots. So they are the same as the mill, 0.625" wide.
This is going to be real easy for a change. So I grabbed a bit of steel scrap and set to work.







First off, the bar was turned down to 0.624", this will allow for a minor irregularity in the mill table, if there is one.
It was then drilled thru with a 5mm drill, and a recess put in the end for a cap screw head. Two were made, both 1/2" long.








They were screwed into position in the slots.






It fitted perfectly onto the mill table.






And a check with a square showed they had done their job.







The RT was bolted down into it's final resting place, and I got the RT perfectly aligned with the quill.







Reset the DRO to zero, just to make sure nothing had moved when I do the next check.







The aligning spigot was dropped into the 2MT centre of the RT, and the adapter was bolted down into position.
Checking to make sure the table hadn't moved at all, I checked the runout of the centre bore of the adapter.

Just under 1 thou runout, in fact as close as I can see, 0.0008".

That will do me just fine.







As an added bonus, I have gained about an inch in throat depth over the previous fitting.







So at this time, I class this as a good result.


John


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## Herbiev (Feb 5, 2015)

Great project and write up. Thanks for sharing.


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## RichD (Feb 5, 2015)

I'm curious whether you added anything to prevent the chuck from unscrewing? Your setup is similar to mine but much better in that the plate and threaded collar are all one piece.

Mine works well considering the two-piece construction, but I always worry about unscrewing it while machining an outside circumference.

On my 3" table it's only good for light work.

I have another table ~5.5" diameter with no worm drive equipped for direct indexing. That one is a little better with a 4" chuck on it, but still not as robust as your setup. I have to rotate that one with a lever while lightly clamped down.

Rich


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## chucketn (Feb 5, 2015)

Bogs, good to see you back in the shop. Please take care.

Chuck


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## canadianhorsepower (Feb 5, 2015)

Verry nice project and presentation  Thm:Thm:

cheers
Luc


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## petertha (Feb 5, 2015)

Nicely done. I'm just about to embark on something similar pretty soon when my new chuck arrives. Its a plain back style chuck that fits D1-4 back plate adapter plate for lathe via 3 front mounting bolts. This configuration will similarly facilitate mount-up to custom RT plate. (I wish I bought this style the first time round, but I didn't know better).

But one thing I did on my older bastardized system that made for speedy setup was:
- zero the RT to mill spindle like you did
- then drop an MT3 arbor in RT hole, it extends proud of RT by 1.5"-2"
- put the chuck over extended arbor segment, gently screw the chuck jaws to the arbor OD, now chuck is also centered to RT (ie without having to indicate again)
- clamp the chuck down to RT in this position, open jaws, remove arbor from top, its centered & ready to work


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## Blogwitch (Feb 5, 2015)

Rich D,
I do make sure I spin the chuck on and it stops with a satisying 'thud'. If I do that, I have never had a chuck come loose. 
I have used this system for a while now in conjunction with a Division Master and it has proved to be superb.

[ame]https://www.youtube.com/watch?v=P1ifPuImERA[/ame]

Peter,
I have seen your posts I think about the D1-4 fitting, but my D1-4 chucks are much too large to be swung about on a 6" RT, that is why I have settled on the Myford nose size. I have made all sorts of adapters to allow swapping between the lathe, RT and the mill, and will be doing the same with the 4" RT that will be the 4th axis on my new CNC X2.

















It really does make a very versatile system, and all of it made from bits of scrap or donated pieces.

John


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## petertha (Feb 6, 2015)

Very nice indeed

- is the ER=looking collet adapter made from existing tool holder, or did you make from scratch?

- do you use 5c collets at all in conjunction with RT?

- when you mill those slotted arcs (I'm referring to metal now), do you find you can cut to dia of endmill, or is it better to directionally climb mill with bit of offset (= net wider slot than endmill dia) for better finish? I haven't done a lot, but mine seem to be a bit ratty looking on one side.


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## petertha (Feb 6, 2015)

Also  ...if you have any RT clamp-down do-dads or techniques you have come to like, I'd be interested to learn.


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## Blogwitch (Feb 7, 2015)

Every bit of my interchangeable tooling I have made myself or modified from another piece except for a 9" faceplate that I bought, as it was cheaper than I could have made it myself by buying the metal in. I usually make things from scrap or bits I have been given by friends, so really, all they have cost me is a bit of my time, plus when I see commercially made items of the same thing, I notice they just don't have the accuracy, In fact, I used to spend a lot of time putting them right for friends who had bought them.
As I said, I have used the Myford thread for a standard because of ease of cutting the threads and it isn't too large. For the ER collet, yes, I made it all myself except for the ballraced nut, which, because it was so cheap, it would have cost me more to make it myself.
Half way down this page you will find the ball raced nuts, and they will be the best thing you could buy.

http://www.arceurotrade.co.uk/Catalogue/Collets/ER-Collet-Nuts-Wrenches-and-Spanners

I have loads of small posts where I made all my fittings and adapters, so if anyone is interested, I can put them up on here for all to see. Some may be useful to you while others might not, purely because of my needs at times for specialised tooling to help me progress a bit further.
I was on here about 3 years ago showing a lot of what I had done, but due to Photobucket losing all my pictures, they are now missing, even though I have now restored most of the pictures back onto there. The posts are now locked, so I can't get to them to put the pictures back. So I will just have to put up new posts if anyone wants to see.

John


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## petertha (Feb 7, 2015)

Blogwitch said:


> due to Photobucket losing all my pictures... So I will just have to put up new posts if anyone wants to see.
> John


 
Sorry to hear, sounds like a pain. Well, take your time. I for one would be interested in your tooling & tricks. Any contributions you care to share will be appreciated.


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## petertha (Feb 9, 2015)

John, what do you think of this idea. I can get an ER40 chuck with MT3 adapter off fleabay for $54. probably even comes with a authentic, multiple rubber stamped inspection certificate 
My thought was drop the MT3 into matching taper hole of RT, now its pre-centered. This one has a drawbar thread on arbor end so hoping I could use a bolt from underside of RT to prevent turning (not sure about this quite yet). The net result if it worked out is rapidly positioned & self centered 'low Y-profile' ER clamping system.

http://www.ebay.ca/itm/330703827597?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

But this got me wondering.. maybe the MT arbor is pressed in & removable leaving the chuck portion. Or maybe the chuck portion can be purchased standalone somewhere, kind of like how drill chucks are attached?

I know your setup is different to facilitate compatibility, just wondering if you know more about the guts of ER's through your tool making?


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## Blogwitch (Feb 9, 2015)

Peter,
Major problem one, how are you going to get the bolt in to draw the taper into the centre of the RT? You will have to remove the RT to do it and so lose your zero position.

I think you will find that the collet head and MT shank are machined as one piece.
Are you sure that your RT has a 3MT down it, most have a 2MT?
But what is stopping you making your own collet head and force fitting a 2MT shank into it. The only problem with that is I would suspect you wouldn't get much material down into it, whereas, because all my tooling is purposely made hollow through them, I can get a piece the length from the top of the ER collet down to the table, over 6".
Just bear in mind though, I have reground so many commercial ER collet tapers in my time that I have forgotten how many I have actually fixed. I have seen them with as much as 5 or 6 thou TIR with a collet and test bar fitted before fixing. I can usually regrind the taper to a couple of tenths TIR. So do be careful with what you buy. 
That is the main reason I make my own, not only are they cheap, but they are deadly accurate as well, plus they do more than a bought one can.
Sorry to piddle on your parade, but please do a lot more research on what you have before spending your hard earned.

John


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## petertha (Feb 9, 2015)

My 6" RT is definitely MT3, not MT2. They vary by brand. Your comments are completely valid
- the underside nut to secure arbor would have to attached with RT off the mill & then the assembly centered only on the ER collet face itself. Not as good as centering on the RT hole, I admit. One is relying on accuracy of arbor + ER chuck
-  the solid vs. hollow is a good point, one would be limited to clamping work only an inch or deep, or whatever the contact distance value is like in normal milling mode

I think a plate with ER chuck integrated (like yours) is the best end result. I do have an adapter plate for 3-jaw chuck, but a) the package assembly starts getting pretty tall & cramping headroom for mill tooling b) it needs to be tweaked into center with a test bar which is not nearly as functional as plopping a chuck on, especially with partially machined work like off the lathe. Oh well, good discussion. You've given me some good ideas.


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