A cheap source of Dividing Plates

[Michael GilliganParticipant @michaelgilligan61133]

This is a stainless steel disk … haven’t checked current availability

It appears to have come from B&M but I got it even cheaper at Barnardo’s Charity Shop !

I will put it on the scanner sometime, to check the hole-counts and accuracy

… looks like there is plenty of  ‘meat’ to tweak things a little with a milling cutter if required

 

MichaelG.

 

[Pete RimmerParticipant @peterimmer30576]

The hole spacings are all over the place Michael. Even if the counts were suitable the irregular spacings would kill the idea flat.

[Bryan Cedar 1Participant @bryancedar1]

If you look at the photo, you can actually see the irregular spacings.

[Michael GilliganParticipant @michaelgilligan61133]

I can assure you that it’s not as bad as the photo [ through the plastic packaging] might suggest.

Having scanned it, I stand by my earlier assessment: looks like there is plenty of  ‘meat’ to tweak things a little with a milling cutter if required.

I don’t have time to do it now, but I will put a CAD overlay on the scan sometime, to demonstrate that.

The hole counts are perhaps more ‘interesting’ than useful.

8, 16, 32, 32, 40, 44, 52, 60

.

If one happened to need any division within the scope of those numbers, it would be a darned sight easier [and cheaper] place to start than a blank disc.

… but never mind, it was just a suggestion.

MichaelG.

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Edit: __ Do please note that I put this in the Materials forum.

[Howard LewisParticipant @howardlewis46836]

Some time ago there was an article abouit making Division Plates, starting with a CD, or DVD and reiterating by using the first to make the second, and that the third (Since each iteration ought to reduce any errors by the ratio of the Dividing Head or Rotary Table) unltil the errors become acceptably small.

Must get round to doing this one day, in the hope of filling in some of the omissions on my HV6.

Howard

[DC31kParticipant @dc31k]

As above, if used on a dividing head, rather than as a simple indexing device, any errors are reduced by the worm ratio of the head.

Compared to something laid out manually it is at least of comparable accuracy, hence the criticisms may be made a little hastily.

I wonder if you could check it by shining a light through one of the holes and marking its outline on the wall, then indexing one hole and seeing by how much the outline changes shape or size.

If I needed something like that today, I’d use one of the many online graduated disk generating programs, print out the picture and use it to produce a plate. The source of inaccuracy in that is lining the pointer up with the printed mark.

It is a bit like change gear calculations: modern technology has taken the tedium out the process.

[Pete RimmerParticipant @peterimmer30576]

It’s not just about hole spacings, although the item in question is significantly affected by that. The concentricity of the holes to the centre hole and to each other is also important.

Apart from that the plate in the pic has all even number holes, so no primes, and not particularly useful counts either.

[Michael Gilligan]

On 19 December 2023 at 13:29 Michael Gilligan Said:

This is a stainless steel disk … haven’t checked current availability

It appears to have come from B&M but I got it even cheaper at Barnardo’s Charity Shop !

I will put it on the scanner sometime, to check the hole-counts and accuracy

… looks like there is plenty of  ‘meat’ to tweak things a little with a milling cutter if required

 

MichaelG.

 

They seem to be popular at many pubs and clubs… but I’m not sure I would want one from that source.

Personally, I think that the advent of 3D printing has made the manufacture of custom index plates a trivial exercise.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

O.K. Pete … I give up [again]

You obviously don’t see any potential in it as ‘make-from’ material

I will either use it, or not use it … no-one else need worry

another one I shouldn’t have bothered posting

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Nice to see you back, Neil

MichaelG.

[JasonBModerator @jasonb]

My CADsuggests the cunning plan of using it for dividing is holed! Even plunging with a cutter to even things up is likely to need a fair size cutter and you wouldrun the risk of one hole over lapping the next

 

Still not fully opening up the arrowed holes and enlarged diameter is just about touching

 

[Michael GilliganParticipant @michaelgilligan61133]

It’s O.K. Jason … I have already conceded defeat

MichaelG.

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P.S. __ I’m obviously thick because I thought 3, 5, 11, and 13 were all prime numbers, and I thought 60 was particularly useful.

P.P.S. __ this obviously isn’t going to go away, so I will put a copy of the 600dpi scan in my gallery, for anyone that wants to labour it.

… I have had enough already.

[BazyleParticipant @bazyle]

Although this particular example has perhaps proved a dud MG points the way to checking out other household items for this and other uses.

[Pete RimmerParticipant @peterimmer30576]

Michael I applaud the sentiment, I’m a big fan of re-purposing items for a use that they were never intended for. In this case, the practicalities are just not there.

[Nigel Graham 2Participant @nigelgraham2]

Hmmm. Not accurate enough for a dividing-plate of gear-cutting quality.

I wonder though if it could be used as the basis for a Rosebud grate? A bit thin so may distort heavily.

(Yes I know such grates have tapered holes, but I am not convinced of the reason often given for that.)

[Chris CrewParticipant @chriscrew66644]

To digress a little: about 30-years ago I acquired a beautifully made GHT Versatile Dividing Head, complete with the differential indexing facility, from the widow of a late fellow club member. As I already had the Myford dividing attachment, with plates Nos. 1 & 2, and had made the Radford headstock dividing attachment, which utilises Myford plates, I decided to use the VDH to replicate Myford plates Nos. 3 & 4. This was a successful exercise, but I have to say that in all the intervening years I have never once had cause to use the additional plates or any of the primes they facilitate. Nice to have but practically irrelevant to me!

[Ady1Participant @ady1]

It looks like its been chain drilled by hand with a two drill head

And I still think your wonderful Michael, merry xmas

[mark costello 1Participant @markcostello1]

One does not know where an idea will lead to. Keep posting as it may help Someone else to have an “aha” moment.

[Ady1]

On Ady1 Said:

“And I still think your wonderful Michael, merry xmas”

Seconded, you are always so very helpful and not often wrong!

Cheers, Martin

[mark costello 1Participant @markcostello1]

It is only a mistake if You do it twice. The first was a learning experience or a setup piece. Fool Me once, shame on You, fool Me twice………

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the moral support, guys

Just to be clear …

1. No, it wasn’t a set-up, although I did post it in the hope of breathing a little life into the forum
2. I have yet to be entirely convinced that it was a mistake .. I did carefully express my opinion that it  “… looks like there is plenty of  ‘meat’ to tweak things a little with a milling cutter if required” [and I may have been mistaken in that assessment]
3. Subject to (2) … what I was really trying to do was point out that an adaptable ‘thing’ can sometimes be a better starting point than raw material.

MichaelG.

 

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