Spindle / chuck flange identification?

Hi,

Can anyone identify the spindle / chuck flange type below? Is it a relatively standard type or unique to Somab who manufacture the lathe?





Thanks,

It looks like a A-6

Here you go...

Yep A1-6 and there relatively common, adaptor plates are typically sub - around $200 integral mount chucks are also pretty common in the A1-6 size range. Worth adding you can also use A2-6 adptors which are common too.

Generally its the larger bore spindles of a given A size that means you lose the A1 inner circle of holes. But i have only ever seen a few smaller chucks mount on thoes inner holes. Most use the outer holes or a adapter plate.

Ideal, thanks for the replies.

Does anyone know a source for these back plates in UK? To be honest I might just make a back plate to mount to my 3 jaw chuck. Does anyone have any experience with doing this? The chuck I have now is a power chuck which restricts the bore to 35mm. I need to use the full 52mm spindle bore.

jim_cliff11 said:

Ideal, thanks for the replies.

Does anyone know a source for these back plates in UK? To be honest I might just make a back plate to mount to my 3 jaw chuck. Does anyone have any experience with doing this? The chuck I have now is a power chuck which restricts the bore to 35mm. I need to use the full 52mm spindle bore.

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Rotagrip - A Type Backplates is one source and a supplier i have used for various items, Cut-well can also supply them i believe.

jim_cliff11 said:

Ideal, thanks for the replies.

Does anyone know a source for these back plates in UK?

[

Click to expand...

Rotagrip, Hockley lists them:

Rotagrip - A Type Backplates

600 group (Pratt-Burnerd) will have them as well

Also Ladner.fr ... and another maker in Spain I can't recall. "Close to" UK pricing, at least until Brexit concludes..

Pricey, regardless, compared to what we can get D1-"X" goods for, out in the Colonies.

To be honest I might just make a back plate to mount to my 3 jaw chuck. Does anyone have any experience with doing this? The chuck I have now is a power chuck which restricts the bore to 35mm. I need to use the full 52mm spindle bore.

Click to expand...

PITA to DIY the short-tapers (D1 is the same). Cone and flat are meant to draw-up sync'ed. Too much like work.

Presuming your 3-J is a manual "scroll" operated, be mindful of size, as its scroll may block direct access to the affixing bolts that go into the spindle. Some of these need back-bolted, but those fasteners then also need to be accessible when mounted.

EG: Affix plate to spindle, bolt it. Affix chuck to plate, back-bolt. Use it. Reverse to use other workholding. Curse profusely. Repeat.




Go and use a different lathe?

Sub the needs-a-big-hole job out?

And/or ..you could be time and money ahead to leave your 3-J out of the mix, go and seek a decent used 3-J already equipped with the proper backplate?

Or.. if not for high volume, an easier to mount 4-J's extra mess-with per cycle might be offset by flexibility for other work?

"many options" - because.. I have a similar challenge with my HBX and adaptors are pricier yet!

Made various calls and managed to find A2-6 back plates either finished or semi-finished for around £150. I certainly couldn't make one for that money. Rota-grip again offered A2-6 back plates at similar costs. I'm guessing an A2-6 back plate would fit directly onto my A1-6 spindle without an issue?

Thermite, thanks for your info. I was told usually the 3-j would have to bolt on from the front. But then obviously there could be an issue with the scroll. If there is room behind the chuck I could bolt it from the rear, which would be better.

jim_cliff11 said:

Made various calls and managed to find A2-6 back plates either finished or semi-finished for around £150. I certainly couldn't make one for that money. Rota-grip again offered A2-6 back plates at similar costs. I'm guessing an A2-6 back plate would fit directly onto my A1-6 spindle without an issue?

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Not within my ken. Check the specs. Published online, more than one place.

Thermite, thanks for your info. I was told usually the 3-j would have to bolt on from the front. But then obviously there could be an issue with the scroll. If there is room behind the chuck I could bolt it from the rear, which would be better.

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Scrolls are sorta "CD/DVD" shapes, largish center hole.

A BIG 3-J is usually clear at center for affixing bolts to match the spindle's holes. Smaller one, only "maybe".

NEW 3-J, you pick for the spindle or buy used, either one preferably already arranged for the spindle nose.

A 3-J you already have to-hand? That one you should check so no "gotcha".