Mt2 tooling adapter?

[leeko]

Hi all,
I have a hardinge TM with a Bridgeport m-head bolted on. The m-head has a mt2 spindle with a 3/8-16 drawbar. There seems to be a fair amount of mt2 tooling available, but the majority has an m10 threaded end.

I do see the occasional 3/8-16 mt2 piece, but they tend to be 2-3x the cost of the metric import tooling. Quality issues aside, is there any way to adapt the m10 tooling to the (captive) 3/8 drawbar?

Thanks

Lee

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[John Evans]

IF and a big if ! If the metric collet is not to hard on the threaded end heli coil it to the 3/8th thread.

[Russ Hanscom]

Is there a way to un-captive the drawbar? How is it retained?

[leeko]

Yes, it can be undone by removing a set screw and (I think) unscrewing a retaining nut. But, it's a few extra steps compared with a regular drawbar, so I'd prefer not to switch back and forth between drawbars. I do that on my Van Norman to switch between nmtb 50 and cat 50, but it's a simple (non-captive) drawbar on that one.

The helicoil is a great idea, thanks!

Lee

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[John Evans]

Lee :Another thought "Timesavers" style inserts they have thinner wall than even thin wall Keenserts. 10MM threaded end when drilled .375 for heli-coil might be a bit shallow on threads for the Heli-coil. Try one and see I recon.

[leeko]

Thanks for the suggestion, I'll give the timesavers a go once I have some tooling in hand

Lee

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[shootnride]

http://www.timesert.com/

Ted

[GlennW]

I do see the occasional 3/8-16 mt2 piece, but they tend to be 2-3x the cost of the metric import tooling.

Why not just sell your present 3/8-16 tooling and convert to metric draw bar and tooling if your 3/8-16 tooling is worth that much and so difficult to find?

[earlgo]

Hah, I have you all beat. I need 3 different drawbars for the Producto-Matic Horiz Mill. 5/8-11 for the #40 NMTB holders, M16x2 for the metric #40 holders and the 7/16-20 cut on the end of a 5/8 rod for the #40 to R8 Adapter. Oh and there is a slide on spacer for the NMTB drawbar for the non-NMTB holders. Fortunately they are not attached and slip into the drawbar holder located nearby.
This in addition to the 3 different sized Wheelcutter arbors.
--earlgo

[spro]

The MT #2 and the B &S #7 offshore collets were a nightmare ready to happen. The ones I bought, were described as 3/8" x 16 . What they did was take M 10 collets and run a 3/8 x 16 tap thru them. They are loose on the original drawbars which means they will ruin those those threads. The collet-eject feature relies on those threads so it fails. Extraction means disassembling top of the head or pounding on the ruined drawbar. So people tap on, hammer on, the original drawbar and permanently alter the precision quill bearings.

[spro]

When I looked inside the collets' thread, disappointment. I hoped it would be better than that. 10mm is near .400" while everyone knows 3/8 is .375. So , by tapping the collets, neither drawbar is correct.

[spro]

The lead is different, so every collet is a die towards screwing our original drawbar . Scopes all over and nobody shows the internal threads and the markings and the thrashing of one thread upon another.