Simple Dividing Head

[old_toolmaker]

I had a project a while ago where I needed to drill several hole circles in a dividing plate having accurately spaced holes. Having no means of accurately dividing a circle I set about building this Simple Dividing Head. I got my inspiration from an article in Home Shop Machinist magazine authored by Ted Hansen. I took the liberty to redesign it to suit my own needs. It is basically a block of 4140 P.H. steel with a few strategically placed holes. It uses mini lathe change gears as dividing plates and it has interchangeable mandrels so suit various applications. One mandrels is threaded M12x1 to accept the spindle accessories from my Unimat DB200 lathe. It is built to be able to be used on my mini lathe cross slide and has its mandrel center line on center with the lathe spindle. The mandrel is locked by means of a split cotter and double ball handle. Mandrels can be switched out and mounted in the lathe for further machining without disturbing the location of the part.

[Hemi]

Now theres an idea to fit onto either of the 2 Unimats I have!!!!!! THANKS for posting this as it is inspiration to make my own!

[old_toolmaker]

Hemi,

Thank you for looking!
It does make a nice little project.

[Hemi]

Hemi,

Thank you for looking!
It does make a nice little project.

Question, because you used Unimat parts, how "close" is yours to the actual set-up on the Unimat? (I'm not sure if you have the whole little machine) so, I'm asking as it would be GREAT for me to use as a gear production tool on my Unimat for replacement gears on scale model trains that you can no longer get parts for...... ?

[old_toolmaker]

Hemi,

I do have two complete Unimat DB200 lathes complete with all attachments.
I am not sure what you mean by "close to the actual setup on the Unimat", but the Simple Dividing Head I built is not scaled for use on the Unimat DB200 but it sure could be made that way. It would be easy to make it at the same center axis height as the Unimat indexing attachment if one so desired. I used 5/8" interchangeable mandrels but you could use easily use 1/2" mandrels. You can also build a worm drive unit to be able to index any number of teeth you desire and you won't be limited to using change gears as indexing masters. The possibilities are endless. Just a few thoughts.

[Hemi]

Dick,
Thats exactly what I was referring too was how close "scaled to a Unimat" is the part you made (I wasn't sure I worded that right but you caught on to what I was trying to say!

Anyway, See, I'm a model builder, a VERY extensive one I might add (I make a LOT of my own parts) but that said, I also work on a LOT of older railroad equipment that the company that made them no longer exists, OR the item simply isn't made anymore, so that said, I like the idea to make my own replacement parts at times and gearing is one of them because some companies only produce parts for so long before they discontinue production making that item obsolete in years to come and then have to either spend 4 or 5 times the amount originally paid to replace that item. SO that said I like to make the parts to keep that old antique becoming item, in good running order.

Thats said, using a gear like you did, is a way to "clone" those old parts quickly! That being said, because its model railroading, I can then modify the item on how it mounts to tghe motor. because those old open frame 12DC motors have LARGE diameter shafting, compared to the newer can motors, I like to be able to make the gear then fit the newer motors which the plus to that is the can motors are much more quiet, require less amps, and run smoothly, (if balanced) and then can be digitized as well where those old motors however aren't anything I just said beside STRONG (the old motors would puller your house in some cases!)

Follow a bit better now? I'd LOVE to know what plans you used for that little gem you made, so I could take your plans and clone them to be functional with my Unimats!!!! -That is if you don't mind! (I could sure use the guidance if nothing else on how you went about things making it!

[old_toolmaker]

Hemi,

You have a very interesting hobby. Or is it an avocation? I have been thinking of drawing a set of plans as built but haven't done that yet. All I have now are crude hand sketches based loosly on Ted Hansen's article in Home Shop Machinist magazine. Those hand sketches would be hard to follow. I would be happy to give you guidance if you decide to build.

[bruce.desertrat]

Interesting coincidence; I just picked up some 96 tooth gears at AS&S https://www.sciplus.com/3116-plastic-gear-58018-p with the thought of building something like this.

This is a handy number because it gets you a lot of divisions out of one gear: 2, 3, 4, 6, 8,12,16,24,32,48 and I hate 1, 2,3,4,oops did I skip a tooth? So I have written a program to make a PDF with common divisions to glue into the gear. Right now it's a prototype, but I should be able to make it fully parametized: OD, ID, #teeth, desired divisions, etc, and stick it up on a website somewhere.

[old_toolmaker]

bruce.desertrat,

Nice find! You should be able to put this gear to good use on a simple dividing head. It is like having a full range of gears in one package. I might just buy a package myself at that price.

[Hemi]

Bruce,
NICE find!!!!! I'm even looking into that one!!!!

Dick,
Please see my PM! Thanks my friend!