Converting Iso 40 to mt

[Guzrik]

I have a boring head with an iso40 taper but my mill has mt3.
Any chance I could just buy an mt3 to round 20x 40mmm? Does anyone recognise this as standard?

 

[Johnnybravo]

You can get machineable blanks. Hardened Mt3 one end and softer on the other end so you can machine it to suit. Like this….

 

[Agroshield]

I am guessing the 20mm is the diameter and 40mm is the length. The soft arbors above are the right idea but the Arc ones are not long enough to have a 40mm shaft and a flange behind it. If you can find an oversize one it would work. Maybe the collective can go out and search for the same but longer.

Is it the same situation with shell mill arbors (https://www.arceurotrade.co.uk/Catalogue/Cutting-Tools/Shell-Mill-Arbors/MT3-Shell-Mill-Arbors-2) - the parallel portion is not long enough and is the wrong diameter and is hardened.

What is the make of the boring head? See if an alternative arbor is available from the manufacturer.

A possible, but really bad option, is a stub arbor (https://www.arceurotrade.co.uk/Cata...g-Saws-and-Arbors/MT3-Stub-Milling-Arbor-22mm). It is long enough but would have to be reduced in diameter (it will be hardened and have a keyway in it so even hard turning with a PCD insert is difficult) and length (it is hardened) and have a new thread put in the end to reatain the boring head (it is hardened).

Edit: what is the minimum diameter flange against which the spindle end of the boring head needs to press? On the arbor shown it looks maybe 26mm. If it would work at 22mm, make a 20mm shaft with keyway and retaining bolt with the rest of it 22mm dia, and hold in an ER32 MT3 chuck. If 22mm is too small, move up to ER40 on MT3.

 

[Guzrik]

Thank you, cannot find a brand, only a number of which google says Natopart. Will look for a local supplier for an adapter.

 

[Wedg1e]

Guzrik, you don't say what make your mill is but if it's anything like my Bridgeport 1ES with its vertical head fitted, any chuck or boring head needs to be as compact as possible as there's not much clearance to the top of the table, even with it fully lowered (the head is fixed height).

 

[Guzrik]

Guzrik, you don't say what make your mill is but if it's anything like my Bridgeport 1ES with its vertical head fitted, any chuck or boring head needs to be as compact as possible as there's not much clearance to the top of the table, even with it fully lowered (the head is fixed height).

Indeed thats also why I wouldn't like to have it in an ER collet (also stability?).

The story is a bit more complicated, i need (would like to) to machine the outside of the 30 mm end of a roller (round140x 1200mm) from my flailmower.
My lathe is way too small to do this in the normal way, but putting a boring head in the headstock and fixing the roller on the cross slide, I might be able to fix this is. (pics will follow)
After this it would be great if i was able to use it in my mill (small taiwanese Rong Fu) which has a mt3 spindle.
Lathe has a conical inside of wich I think is mt4, so I would add a mt3-4 adapter. Otherwise I will need to machine the custom cone.
If i find a broken mt4 drill for a good price I migth start with that.

 

[Agroshield]

...putting a boring head in the headstock and fixing the roller on the cross slide

Just grip the non-moving part of the boring head in a three jaw chuck for use on the lathe, or make up a straight arbor for it. The end of the arbor you grip in the chuck does not need to be concentric with the 20mm dia. end that goes in the boring head. The boring head body does not need to run concentric. However 'badly' you chuck it up, it is impossible for the cutting tip not to describe a circle about the lathe axis of rotation. The only important feature of the arbor here is a snug fit inside the boring head body so it does not rattle. Chucking on the body means it cannot rattle.

If you are OD turning with a boring head, you need opposite hand tooling or to run the machine in reverse.

Thinking about it some more for the mill, you could buy a blank arbor as suggested above, reduce the length by maybe 1/2 or 2/3. Then bore a hole (might need to be stepped) in the end, loctite and cross pin in a bit of 22mm dia. stock. Then once the glue has dried, turn the 22mm dia down to 20mm dia., tap the end and cut the keyway. That would get you the minimal overhang you need. I looked around and the only people who have longer soft arbors than those above are RCM-Machine and theirs are only 40mm long, so not much gain.

 

[gaz1]

iso 40 to mt3 does exist

ISO - Morse Taper Adaptors (Drawbar Type) - Arc Euro Trade

Used to adapt ISO30 or ISO40 spindles to MT2 or MT3. For drawbar use.

www.arceurotrade.co.uk

 

[Johnnybravo]

iso 40 to mt3 does exist

ISO - Morse Taper Adaptors (Drawbar Type) - Arc Euro Trade

Used to adapt ISO30 or ISO40 spindles to MT2 or MT3. For drawbar use.

www.arceurotrade.co.uk

His machine isn’t iso40, his boring head backend is…