Dividing head for lathe - Myford vs BS0/1?

16DP x 100 teeth is over 7 inches outside diameter.

Only 6 3/8” by my calculator.🙂

a lot of fine passes.

DP16 gears would only need one cut/tooth I would have thought (at least for cast iron).

Oh well, a doddle then.

Thats true, I've done a 16dp 90 tooth iron gear on a BS0 with the Centec, but had to use the horizontal arbor in the vertical head to get the height. Even ignoring work holding the blank and cutter already eat up a bit more than 4" of daylight between centres.

You occasionally see a Jones and Shipman 1mt divider on ebay, they don't go for much and look like the Alan Timmins head except the dividing plate is direct mounted to the shaft and would need modding to take advantage of the worm wheel gearing. It should fit the rear toolpost slot.

You might want to have a rethink about whether a dividing head is what you really need. Try thinking how someone would have done this fifty years ago, even on a smaller lathe.
eg after turning gear blank use the usual strip of paper round a wooden disc on the rear of the mandrel, or a 50 tooth changewheel indexing peaks and troughs to align and drill 100 holes a little inside the rim of the blank. Then mount the gear cutter between centres and the blank on a vertical stub arbor on an extension plate if necessary on the cross slide and index with the holes you previously made. Sure the teeth have the curvature of the cutter but if that is a problem repeat shimmed at different heights. Save £200.

As we give our advice to the OP it is, perhaps, worth bearing in mind that, as I understand it, the equipment he has available is similar to this:

(image from Lathes.co.uk)

The OP will have a Mentor milling head rather than a Myford/Rishton but they are similar. The obvious solution, to me, is to mount the gear cutter on an arbor in the milling head and the gear blank on a dividing head on the cross slide. I can envisage 2 problems. The first is that there may not be enough travel on the cross slide to withdraw the gear blank far enough away from the gear cutter. The second is that the gear blank will have to be mounted on an arbor and will need clearance between the cutter and the dividing head chuck. This means that the blank arbor will need tailstock support. I don't think (could be wrong!) that the Myford or GHT types have sufficient clearance to the support arm for the size of gear the OP wishes to cut. The illustration above shows a milling table attached to the cross slide. Perhaps a longer table could be arranged that will accommodate a tailstock for the dividing head.

Stay well everyone,

Rod

You've understood perfectly Rod. I waited around a year for a Myford/Rishton head to turn up, then this Mentor popped up so I jumped on it. So my setup is virtually identical, though somehow the photo looks much more appealing.

The 100 tooth is something of an aspiration. I'm looking to cut 56 teeth at 16DP in the short term.

Also, I'm not set on any particular method, so I've found this thread particularly useful - thanks to all.

Once the mill is bolted to the lathe, I'll try various configurations and post sny results here.

All the best, Paul

Ah well tha6t puts a different slant on things. It looks like the pictured type of milling head would be the way to go for cutting larger gears like DP16 at 50 to 100 teeth. You could hold the blank on an arbor in the lathe chuck and use change gears for indexing for many tooth counts. But might be a bit limited if you have the QC gearbox and limited numbers of change gears to play with.

In which case, back to finding a BSO type dividing head that would fit in the daylight under the milling head while bolted to the cross slide. Or even one of those rotary tables that can be mounted sideways and fitted with index plates. That would be a much more solid set up than trying to cut large diameter gears on the Myford dividing head and vertical column perched up on a rising block. They really are pretty flimsy and best suited for cutting small model gears etc.

The mill spindle is a fixed distance from the lathe spindle as I read it so that rules out the headstock division for gear cutting if the cutter is to be held in the mill.

regards Martin

.

True ... but it doesn’t rule out the possibility of using the mill as a power source for a cutter-spindle mounted on a vertical slide; which might be a tidy [and powerful] alternative to the traditional ‘overhead’.

MichaelG.

Well yes but you do then have to get a cutter spindle and a headstock dividing head rather than just a crosslide dividing head.

regards Martin

There is [quite obviously] no single ‘best’ way of working ... or we wouldn’t be having this interesting discussion.

I would, however, like to share this video, which demonstrates using the Schaublin 102 with a cutter spindle on the vertical slide, and the dividing done in the headstock.

**LINK**

https://youtu.be/u0Ngmzqf2xg

MichaelG.

Well here's the solution I finally came up with - a Coronet Minor Headstock!

Bought on a whim from you-know-where for £26, it could have been made for this job! The only mods needed were three holes for registration pins and mounting to the cross slide; a couple of collars, and a simple sprung indexing pin. Of course, you have to already have a gear with the required tooth count. It's shown here with an 89 tooth DP 16 gear blank in Tufnol.

The headstock has an external thread which a 3/4" pipe fitting bolt fits, and an internal thread, which I've yet to measure. Here's a view from above, showing the mounting holes and indexing pin:

I had to swivel the vertical mill attachment so the reference gear doesn't hit the column. I haven't dared try any cutting yet. There aren't really enough threads on the external front thread to be confident of good clamping, so I'll make some sort of front clamp using the internal thread before I try it out. The indexing pin is also 'blind' - hidden behind the casting, so there's plenty of scope for a mark 2 if the concept works.

Let me know if I'm about to cause a big accident.

All the best, Paul

I would include some form of marking so you can spot wether either disc slips on the shaft.

Also if you have stops of some kind for each end of the cross slide travel, it's all to easy to move to the next index with the cutter still partially in the blank.

The mandrel of my Coronet Minor (mentioned in a recent thread) had a ¾" British conduit thread, 16 tpi, Whitworth form.

Best regards,

Swarf, Mostly!