Alexander Toolmaster Dividing Head

[Graham Clark 3Participant @grahamclark3]

Any suggestions where I can acquire a support arm for the dividing head on my Alexander Toolmaster milling machine. Also looking for dividing plates to suit.

[DC31kParticipant @dc31k]

A picture of the item or a link to a picture (e.g. lathes.co.uk) would relieve all your potential helpers of the trouble of seeking it out for themselves.

Some nominal dimensions would also help (e.g. dovetail size and spindle centre distance).

These would also give an opportunity to suggest alternate sources of unicorns (maybe a Centec overarm).

[Graham Clark 3Participant @grahamclark3]

[JasonBModerator @jasonb]

Bit of a Unicorn as hinted to above.

I would think making your own would be a more likely route of getting a usable dividing head. If you like the rounded look of the original then it would be a fairly simple item to make a wooden pattern for and have cast, then just machine the dovetails. If you are not worried by looks and just want a machine that can be used then cut from bar, possibly with the dovetail from a separate strip screwed on. Optional if you round over the edges or just leave it square.

With DROs making a set of plates is not particularly difficult these days.

[Phil PParticipant @philp]

I have a genuine Alexander Master Toolmaker dividing head overarm (not for sale)
If you need any measurements let me know.

Phil P

[Phil PParticipant @philp]

I also have the three original dividing plates. This table shows all possible divisions which is calculated using factors.

This method works for any dividing head and plate configuration. I suspect not many people will have seen this method, but it is super simple and foolproof.

The factors across the  top are all the numbers that will divide into the number of teeth on the worm wheel.
The factors down the LHS are the numbers of holes in each circle on the plates.
Simply look where the factors cross each other on the table and multiply the two numbers and that is an available number of divisions for your setup.
You still need to work out number of turns and spaces in the normal manner, but this table gives you a quick reference to see all the divisions you can get.

[Graham Clark 3Participant @grahamclark3]

Thanks for the info. I had hoped someone would have an original arm available but in the meantime I will make up a support and plates I can use.

[Adam HarrisParticipant @adamharris13683]

Graham I have a Deckel one that I would sell including the sliding tailstock – it actually is complete with the dividing head also but presumably you do not want that? Give me the dimensiions to check it is a match and PM me. Adam

[Graham Clark 3Participant @grahamclark3]

Slide widths are 2.56 and 2.13 inch

Length of slide 9.5 inch

Base of slide to centre of spindle 4.2 inch

Plates are 5 inches

Would consider buying head as well as arm – let me have the prices

[Adam HarrisParticipant @adamharris13683]

Graham I will pm you tomorrow – it is at the very back of the workshop. It looks externally in better condition than yours but I have never used it (on account of the considerable weight for my old bones!) and it needs some fettling to get it rotating. I am in Oxford – where are you based?

[vintagengineerParticipant @vintagengineer]

You use the same arm and bearing that double s up for the horizontal milling arm.

[vintagengineer]

On vintagengineer Said:

You use the same arm and bearing that double s up for the horizontal milling arm.

Are you stating that as a fact or putting forward a speculative guess?

Please look at the pictures on lathes.co.uk (https://www.lathes.co.uk/alexander/)

The outboard horizontal arbor support is made to support a horizontal arbor. The arbor rotates.

The analogous piece for the dividing head has a small diameter longitudinally adjustable dead centre in it.

The two pieces differ.

 

 

 

 

[Adam HarrisParticipant @adamharris13683]

Jason, about 10 years ago I had a local casting business (Swan Foundry in Banbury) cast one of these from an original for an Aciera F3. A quick and simple and inexpensive job. Sadly they went bust a few years ago and since then I have not found anywhere within 100 miles offering the same one-off service. Can you recommend anyone? Adam

[DC31k]

On DC31k Said:

On vintagengineer Said:

You use the same arm and bearing that double s up for the horizontal milling arm.

Are you stating that as a fact or putting forward a speculative guess?

Please look at the pictures on lathes.co.uk (https://www.lathes.co.uk/alexander/)

The outboard horizontal arbor support is made to support a horizontal arbor. The arbor rotates.

The analogous piece for the dividing head has a small diameter longitudinally adjustable dead centre in it.

The two pieces differ.

I use the same over arm for the dividing head and horizontal milling.

 

 

 

 

[Adam Harris]

On Adam Harris Said:

Jason, about 10 years ago I had a local casting business (Swan Foundry in Banbury) cast one of these from an original for an Aciera F3. A quick and simple and inexpensive job. Sadly they went bust a few years ago and since then I have not found anywhere within 100 miles offering the same one-off service. Can you recommend anyone? Adam

Get it 3d printed? See other thread.

[JasonBModerator @jasonb]

Is that the thread where I said that I did not think metal Printing was the answer to everything? I think printing would be quite expensive due to the volume, if anyone wants to give the the O/A sizes of the arm I’ll see what one might  cost. But if anyone else wants to play with FEA and work out of a solid item is really needed it would be interesting to see the difference. I still think a fabrication would be the cheapest option.

Adam Castings over the last few years were coming form Graydon Castings but they have gone down hill which is a pity as they were reasonably priced as they tended to charge by weight.

I had some done at the end of last year using a mix of CNC cut and 3D printed PLA patterns by East Coast Castings. The iron was a lot nicer, good castings if a little over enthusiastic with the grinder when fettling. From the pricing it seems they have a charge per item and then a material cost on top of that which seems a more logical way to price but does work out at least twice what Graydone were charging but would not be so bad on a heavier part where the material cost would be the higher of the two parts.

Home

I posted the patterns and they sent them back with the castings but can understand people with an original part not wanting to post that.

[Adam HarrisParticipant @adamharris13683]

Many thanks Jason, I may give them a try. Norfolk not too far from Oxford.

[John HinkleyParticipant @johnhinkley26699]

East Coast Castings is the foundry used by Dom Chinea (Repair Shop/Dom Chinea’s Cornish Workshop) to have the castings poured for his Ranalah wheeling machines and the reduced sized versions.  From what you can see on the small screen, the castings appear to be of good quality, though no doubt they are expensive, but I suppose that’s as much to do with their mass as the casting process itself.

John

 

[Phil PParticipant @philp]

I have been out and looked at mine, and can with 100% certainty say that the horizontal milling overarm and the dividing head overarm are significantly different sizes on my Alexander Master Toolmaker.
I cannot see how anyone would be able to use the same overarm for both purposes.

Phil P

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