Boxford hand crank spindle drive

[MetalhackerParticipant @metalhacker]

I have a Boxford 500 VSL, which, as you may know, has a huge central spindle hole. The latest MEW has a design for a titchy Myford sized one. To upscale to the 1 1/2" plus size needed for the boxford would be quite an undertaking, and would the mandrel expand enough at that size to lock the crank to the spindle? I have somewhere seen a central insert with a diagonal cut across it so one part would slide across the other and lock crank to spindle. Would this be a viable alternative to the centrally expanding type. I would also be using it as a mount for a gear based indexer. What do you all think?

[MetalhackerParticipant @metalhacker]

[Neil WyattModerator @neilwyatt]

Hi metalhacker,

My 'floating collet' design appeared in ME 4230. 17 Sept 2004.

The two loose segments held in place by a keyring (an o-ring would do) work really well and could grip at any diameter. It has the advantage of only taking up about 1 1/4" of spindle length, much less than most designs.

I silver soldered a short lever (a flatpack furniture spanner) to the nut and now fitting and removing is a single handed 2-second job.

It also works as an indexer, described two issues later. Mike Chrisp expressed the view that the spindle bore may not be concentric, causing errors, but I measured mine and it's within a thou even at the tail of the mandrel.

Neil

Blimey, that wall has gotten grubbier in the last ten years!

Edited By Neil Wyatt on 04/10/2014 19:41:52

[Clive FosterParticipant @clivefoster55965]

I have an in-spindle depth stop which uses a couple of floating O rings spaced an inch and something apart by an alloy cylinder arranged so as to be expanded against a flat by short cones when the screw is tightened. Hafta think about the orietation of the cones so that the O rings expand when the screw is done up but drop free when loose. Get it wrong an one will hang up and self tighten when removing.

It seemed quite firm when tested on a piece of scrap tube but its too small for my lathe so I've never tried it in anger. Came in a box of "useful shop made stuff" it appears to have seen some use so I imagine the idea is sound. Certainly the bits I used out of the box worked well.

Clive

[MetalhackerParticipant @metalhacker]

Thanks Neil,

that looks a real possibility. Is that ME Edition in the electronic archive?

Andries

[MetalhackerParticipant @metalhacker]

Hi,

I have checked out that article and the subsequent one on the divider, and it looks as if it could be the right idea for the VSL, if a little bigger. I will sit down with my thinking cap on and see how I can incorporate gear dividing as well as division plates which I bought years ago for my Unimat. It may be a multi function spindle attachment in the end!

BW

Andries

[SteveIParticipant @stevei]

Metalhacker,

From page 261 of G.H. Thomas book workshop techniques he describes a head stock dividing attachment for the Myford 254+ lathe based around an expanding mandrel. This may be of interest to you as it no doubt could be adapted for a crank handle.I do not know off hand which ME edition (if any) this article was originally printed in.

Steve

[MetalhackerParticipant @metalhacker]

Thanks Steve,

I do have the book, so I will have a look

Andries

[BazyleParticipant @bazyle]

With such a large spindle hole you might try a design that leaves a hole through for long stock, and perhaps even allows a collet closer through too.

[MetalhackerParticipant @metalhacker]

I was thinking of an arrangement the allows one to bolt on various accessories, like dividing gears and worm wheel, handle and watchmakers dividing plates. Will do some sketches when I get time but the hollow mandrel idea is good. I have an R8 adaptor for the spindle nose which will hold my ER40 collets so i could use the collets and divide at the same time!

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