Chuck backplates

[Kiwi BlokeParticipant @kiwibloke62605]

At some time in the future I will have to make some chuck backplates for an Emco V13 lathe. The spindle nose is to DIN 550 22, size 4, so a short taper provides radial alignment, and the backplate clamps up to the flange. A really-well made backplate will ‘stick’ to the spindle tightly enough to support the chuck when the clamping bolts are loosened. Here in New Zealand, getting materials in small quantities can be a big problem. I think a malleable cast iron would be the best for such a backplate, but I suspect the best I’ll be able to get is some variety of (Chinese) steel. Would this be likely to be OK? Would there be a risk from similar materials being in tight contact? Is steel routinely used for backplates? Am I over-thinking this (as usual…)?

[JasonBModerator @jasonb]

I’ve got a couple of steel backplates, probably EN3. I also made a similar DIN backplate for the Emcomat 8.6 that I had previously from unknown steel

[Andrew CrowParticipant @andrewcrow91475]

I have also made backplates from mild steel without any problems, however after cleaning the spindle nose etc I usually smear a drop of light oil around just to prevent any rusting/binding.

Andy

[egaParticipant @ega]

There is a YouTube video by This Old Tony describing the successful making of a steel L0 backplate.

[Andrew TinsleyParticipant @andrewtinsley63637]

There seems to be a lot of old wives tales about making chuck backplates out of anything but cast iron. For what its worth, I have chucks with backplates made out of steel and cast iron and there appears to be no difference, that I can tell. Obviously a little lubrication goes a long way to stop corrosion and sticking.

Andrew.

[egaParticipant @ega]

I think that back then the old ladies found CI easier to machine!

[Grindstone CowboyParticipant @grindstonecowboy]

I have heard that cast iron provides a dampening action on vibrations and therefore *could* prevent chatter.

I have both CI and steel backplates and can’t tell any difference.

Rob

[Clive FosterParticipant @clivefoster55965]

From a production cost viewpoint a cast iron backplate blank can be made very close to final size minimising machining time and material turned into chips.

Wonder which is more faff and cost. Casting a simple backplate or chopping a slice off a big round bar.

Possibly not so much of a worry on ME / Home Shop size machines but the D1-5 backplate on my 14″ Taylor chuck is a big lump and that isn’t a particularly big chuck for the larger variety of industrial machines. I’d be unsurprised if cast iron became favoured simply due to being the sensible way for biggish chucks soaking them all from the same material meant that various process optimisations could be developed and exploited.

Clive

 

[JohnFParticipant @johnf59703]

Kiwi bloke, You may find this interesting as an aid to gauging the taper for fit,  a quite difficult thing to measure !

https://www.youtube.com/watch?v=e0_oKnsv4DM

I remember seeing this chap doing a video making a backplate for an Emco Super 11 and at that time he was using slip gauges plus a slip gauge accessory set to measure the diameter at a set datum point — can’t seem to locate it now but this tool is worth making.

John

[Nicholas FarrParticipant @nicholasfarr14254]

Hi, I’ve made a few steel back plates, but the biggest one was a 6″ one. Cast iron ones are quite suitable for most lathes, however they have restrictions on very high speeds, as they may not be able to stand the centrifugal forces on them, and so the bigger the diameter, the slower they should go, this also applies to cast iron chucks and faceplates.

Regards Nick.

[Clive Foster]

On Clive Foster Said:

 

Wonder which is more faff and cost. Casting a simple backplate or chopping a slice off a big round bar.

 

Depends on your backplate. A Myford one for example needs the boss out the back for the thread so a casting saves machining time and material. The Far Eastern and Emco lathes are really just a disc with a hole so a lot less machining needed as if you get them sawn near size it is only a facing cut or two each side. Both need a hole in the middle and smaller mounting holes..

[old martParticipant @oldmart]

You can use cast iron, SG cast iron or steel whatever floats your boat. I have used all three and suspect that the one on the little TOS 80mm chuck is stainless steel.

[JasonB]

On JasonB Said:

<p class=”bsp-quote-title”>… A Myford one for example needs the boss out the back for the thread …</p>

Certainly, but some Myford backplates position the thread and part  of the register inside the body of the chuck thus giving less overhang and less depth behind the jaws. I think the near chuck in my photo was made by Burnerd specially for the Myford spindle nose. The other chuck is the more usual type and is getting  on for one pound heavier.

[Alan CharlestonParticipant @alancharleston78882]

Hi,

I have a couple of chuck backplates for an Emco V10P lathe (see picture). I don’t have the lathe any more. The OD of the machined face is about 80mm and the ID of the hole is about 45mm. I’m not sure if they will fit a V13. If so let me know. I’m in Auckland.

Regards,

Alan C.

[Kiwi BlokeParticipant @kiwibloke62605]

Thanks everyone for your reassuring comments: it looks like I’m overthinking things, as usual… I guess it’ll be steel and anti-sieze goo – and crossed fingers.

Alan   Thank you for the thought. Unfortunately, the spindle and chuck sizes for the V13 are quite a bit bigger than the V10P’s. Try your luck on Trade Me? However, things don’t seem to be moving, these days…

JohnF   Yes, in fact it was Stefan’s video (excellent as always!) that reminded me of the future need to get around to solving the V13 backplate problem. So much to do – so little time!

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