Rotary table quality?

I haven't seen one of their rotary tables but if their milling vices are anything to go by, I wouldn't hesitate. I have a small tilting milling vice from them that is beautifully finished and thoroughly accurate - a nice piece of kit to look at and use. I suspect therefore that their quality is very good. ISTR that I got it from Chronos.

Mark

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Thanks - I'll take that as an indication that the Soba stuff isn't grotty, then. :-) Just did the 'click buttons, stuff shows up' thing on the Chronos eBay store.

I bought one a while ago. I've not used the dividing set up yet but have had no real problems with the rotary table and tailstock. General quality is good and, although the graduations are untidy, they are accurate. One minor niggle is that the mounting surface for vertical mounting projects slightly above the level of the table when used horizontally. Thus large work mounted on the table has to be spaced off a little to clear it. When I have a few spare moments I intend to machine a little off the mounting to rectify this.

Russell.

I have the 6" Soba RT and it seems nicely made and is an absolute snip at the current price. Mine does not have the problem mentioned below with the mounting base protruding above the table, but I am still going to need to machine the vertical base because the T-slots on my VMC are not far enough apart to fit when used in vertical mode.

I haven't used it enough to give you an opinion on it's accuracy but I don't anticipate any problems based on my playing so far. If you intend fill in the gaps in the dividing range by making your own plates then you should allow for making new sector arms as well because ISTM the ones supplied won't be very practical for plates with more than about 50 holes.

I also bought the Soba 4" modular milling vice and it seems also nicely made and quite accurate but jaw lift is a bit of a problem - any parallels near the moving jaw come loose straight away under even light cuts. I don't mean to hijack your thread, but if anyone knows a cure for this I'd be interested to know it.

Cheers,

David

Maybe this is an issue which the makers have addressed.

That's something I'll need to check when it arrives. What are the spacings on the rotary table?

I'll cross that bridge when I come to it. No plan for custom dividing plates just now - don't even have any specific plans to use the ones that come with it (apart from maybe making an abney level at some point). I just reckoned that the price for the full kit was very good compared to almost any other

Tap the job down with a hammer while tightening? Or, shim appropriate bits of the vice, or replace it.

Righto. Sounds usable to me.

I'll check mine out for this when it arrives.

Mounting slots for vertical mounting 15/16 in long on 4 7/16 spacing. I just use a pair of clamps for mounting.

Russell.

Use a 'pull-down'.

You will need to use a fixed font to see the workpiece below resting on two parallels, with a parallelogram shaped packer between the job and the moving jaw. This is a 'pull-down'. Use another parallel to rest it on while you initially grab everything, then slip this parallel out and tighten up. If the proportions of the pull-down are right, the friction will hold things in place and the offset forces (a moment) result in a downward force on the job. If the proportions are wrong, the whole thing goes poing in your face as you apply pressure.

If the pull-down is too thick, you can cheat by tilting it a bit, clockwise in the diagram. It does not need to, and should not, have sharp corners. You can take a bit of flat stock and file a bevel on opposite corners for just over half the thickness.

Another narrow packer can usefully be placed between the fixed jaw and the job, opposite the pull-down. This ensures that a not-perfectly-square job is sitting flat for making the top parallel to the bottom.

Conversely, where the job is pushed directly against the fixed jaw, you are making a face square to an existing one, and one parallel underneath is theoretically sufficient.

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Dunno, I'll have a look when I get home tonight...

Tried tapping it down, I'll have to have a look at the vice. Maybe there is provision for adjusting the tightness that the moving jaw is held down.

Cheers,

David

This sounds useful - how much of a bevel do you need ? I'm guessing a millimeter would be enough ?

Also useful...

This may actually have been part of the problem - I'm not certain the faces I was gripping were parallel to each other and it might have been an idea to put a bit of round bar between the work and the moving jaw.

Thanks for the help,

David

parallel to

underneath

Trap a piece of 16 gauge aluminium welding wire horizontally between the jaw and the work. It will deform as you tighten the vice and allow for non-parallel workpieces.

AWEM

A quick sketch told me it wouldn't fit my mill in the vertical orentation. It arrived, and it doesn't fit. Clamping for me as well...

No need - it doesn't fit the mill's slots when vertical.

Worth a look. That said, I tried to 'fix' a cheap drill press vice that had bad jaw lift by removing some material here and there. It ended up with the moving jaw sitting too low and the leadscrew was binding. It's now in the 'experience' box...