It would look like this. Same basic shape as an AXA 250-104 adapter but 1.5" longer on the back to accommodate the length of the R8 collet.
So I have a CNC mill and a lathe that I just converted to CNC. I have a Yuge investment in TTS tool holders for the mill. What I am looking for is an adapter for an AXA toolpost that holds a R8 collett so I can use my mill tools like drills, reamers, center drills... on the lathe without screwing with their offsets on the mill.
Here is what I am thinking of. This is just a boring bar holder with a 3/4" hole in it. What I would like is an R8 collett instead of that clamp bolt on the top.
Has anyone ever seen or heard of such an animal? Is there any reason why this would not be a good idea?
I don't have the tools yet to make one of these. Would anyone be interested in making one for me?
Bob
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It would look like this. Same basic shape as an AXA 250-104 adapter but 1.5" longer on the back to accommodate the length of the R8 collet.
Last edited by maxspongebob; 07-07-2019 at 07:25 PM.
No comments?
That must mean that this is a fabulous idea and yall are just mad you didn't think of it first. LOL.
Other than a boring bar I can't see the point in mounting anything in the cross slide that couldn't be mounted in the tailstock - drills, reamers, taps and dies etc.? You spend as much time getting the tool centred as you would swapping them around - surely easier just to swap in a different AXA tool holder?
I have the same investment in TTS and this is an AWESOME idea. Thinking of a quarter turn lever clamp on the back to clamp/unclamp the tool. It wouldn't need to be R8 necessarily. Maybe you could find a 5C or any other clamping mechanism for 3/4" shank.
Not cheap: Aloris 5-C Collet Holder - AXA-5C - Penn Tool Co., Inc
Lots on ebay for ~$150. Some have lever closers
5C collet block
Make a dovetail adapter that bolts to the collet block. The cheaper blocks aren't super-hard; should be able to drill & pin something in place. Looks to be enough meat above and below the bore to install a series of 10-32 screws - maybe 4 each top and bottom - and bolt on a 1/4" thick backer with integral dovetails. Maybe 3/8", and then you could install a small height adjuster screw to get it on center.
Looks liek the dovetails are about .381" deep, so you could probably start with some 2x3x .750" tool steel and then harden it.
3/4 5C collet, twiddle the alignment and you're in business. Won't be super rigid, but would be super convenient. I blieve the AXA system uses the dovetails to pull the machined flats together so the forces trying to spread the dovetails apart wouldn't be horrible.
I suddenly find myself wanting one...
Well, since my lathe is CNC, using the tail stock for anything other than a center is using the lathe in manual mode. Just like any other tool in a CNC lathe the offsets are set once and not changed again after that. Since the AXA tool holder is position repeatable, if you mount a TTS tool into it then all the tools are repeatable as well. Whats more, the tool holder will have an offset that when added to the tool offset give you the position of the tool.
Maybe it wouldn't work perfectly out of the box, but with a simple modification it could work. I'm thinking of a 3/16" thick steel disk with a 3/4" clearance hole in the center and two counter sunk holes at the edges. Drill and tap holes on either side of the 5C taper on the AXA block and screw this cover over the collet once it is installed. The TTS shank goes through the hole in the middle to be clamped by the collet (less the 3/16" of contact due to the disk - whatever) and the shoulder seats on the flat face of the disk.
I guess I don't see why the 3/4 boring bar holder isn't good enough. They are cheap too.
If you really want a collet holding it then why not an off the shelf MT3 AXA holder and a MT3 3/4" collet.
https://www.shars.com/morse-taper-ho...3-type-153-axa
https://www.shars.com/3-4-3-morse-taper-round-collet
Latest update:
I buy my Tormach toolholders from a seller on Ebay. Yes, they are in China. I have always gotten good results from their equipment, so I sent them a message with the drawing to ask if they will make this R8/AXA adapter. They said yes. They expect the price to be $85 US.
This is fabulous news. I told them that I would see if anyone else is interested.
https://www.ebay.com/sch/i.html?_fro...rs=spell_check
Also, if anyone is interested, their Tormach ER20 holders are now ATC compatible. 10 for $119 US.
This just got extremely interesting. Yes, I'm interested - but in a BXA holder rather than AXA.
And I've purchased from that vendor before as well.
Ok, so I am working with this vendor to have the toolholder made. They are asking what the tolerances should be for the dovetail in the AXA block. I am drawing a blank finding this data. Does anyone have a drawing of what the dimensions should be? How about surfaced finish?
This is what I have come up with. The critical items are the surface finish of the dovetail mating points, the surface of the R8 taper, the width of the dovetail, and the angle and depth of the R8 taper. The rest of the dimensions are not critical except for parallelism of surfaces and the concentricity of the taper.
Any input from others would be very appreciated.
The manufacturer is still working on building the tool holder, but I have done some further investigations on how to use it.
Here is a video of how it should work.
First, with regard to tool offsets, the face of the tool holder itself will be used as the zero offset in the Z axis. This means that the Z offset for each tool installed in the lathe will be the same as it is installed in the mill. Also it means that whatever method you use to measure the tool length can be used to determine the Z offset for the lathe. Second, the X offset is the same for any tool installed in the holder. This will align the tool with the centerline of the spindle. Finally the Y axis, or the depth of the AXA holder on the toolpost will align the tool in the Y axis with the centerline of the spindle.
Piece of cake.
The company in China that I was talking to about this has finally gotten them machined.
It is complete and it works great. I took some quick measurements of the holder and the dimensions are spot on.
Some of the edges were a bit sharp so I had to put a chamfer on them, but the surfaces and dimensions are good. I cut down a screw for the R8 key and borrowed a Y axis stop from another tool holder. The R8 collet is a Tormach collet so that the Tormach tools index in the Z axis with the face of the tool holder.
I installed a Grade 8 7/16-24 bolt to tension the collet. I might make a nicer drawbar in the future but for now this works.