Yiyen Dividing Head Questions

[vocatexas]

When I bought my little Sajo mill, it came with this dividing head on it. Has anybody had any experience with this brand? I've looked on the internet and can't find any info on it. I think it's a Tiawanese knock-off of a Brown and Sharp. Also, would it be a B&S No. 0, 1, or 2 and what are the differences? It came with the change gears and some accessories, but I don't think all the parts are there to use it to make helical gears. I may have to make some parts to do that.

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www.hobby-machinist.com

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[Dabbler]

It looks very much like a B&S #1 clone. Download a B&S manual and see if things make sense for your DH. I have the 'complete' kit, so we might compare notes offline.

 

[benmychree]

I don't think that B&S made a #1 dividing head with spiral capability as the one pictured has, to my understanding, only the #2 has that capability, it can also perform differential indexing if one has the shaft that carries gears at the back end of the spindle and connects a gear train to the lower shaft that turns the dividing plates; this allows prime numbers to be divided, such as 127, the metric translating gear. A picture of the change gears and any other accessories would be helpful. The #2 head has a center height of about 5 1/8". I have an original B&S #2 universal head with all the accessories, and occasionally do helical milling.

 

[Dabbler]

@benmychree I don't know if B&S #1 came with the accessories or not - as my B&S #1 is a russian clone with all the additional gears for helical. There were 2 styles made: one with a separate shaft (I have seen these on #3 (what a big sucker), and ones that tap into the worm gear normally carries the dividng plates.

A photo of what he has will help us both to get him complete. My kit must have 26 or 27 gears in it, along with other parts for setting it up.

 

[benmychree]

The standard change gear set has 10 gears, plus the idler bracket for reversing direction of rotation, makes 11, then there are additional gears in a set of eight that expands the number of divisions possible, including all divisions from 383 to 1008, according to their book, "Practical Treatise on Milling and Milling Machines". so if one had the extra gears, the total would be 18, plus the idler gear, which I think would not technically be a change gear. I have never needed any of the additional change gears for any indexing that I have done.
The dividing head is not just for indexing and spiral cutting, it can also be used for linear dividing, the book details the setup, where the DH spindle is geared to the table screw and the indexing crank is rotated to move the table a certain amount; I used it to graduate several blacksmith rules that I made for myself and friends, 10 turns of the crank gave 1/16" graduations, one turn gave 1/128", that is 1/2 of 1/64th inch, other gearing could be used to divide odd graduations for verniers or shrink rules, etc. For a 12" rule, that is a lot of cranking, so I modified and made extra change gears for a rack milling attachment that was made to space rack gear teeth, it uses a one revolution stop clutch and 4 change gears per setup and will divide both diametral and circular pitches. This speeded up the rule making quite a lot.

 

[Dabbler]

I haven't opened the gear storage box in 2 years - I think there's a set of 6 idler gears in it, making up some of the difference. I've never used the gears for helical milling, and neither did Bert, and he owned it for 38 years before me...

If you don't mind, I'll document what I have for comparison, and perhaps we can put the inventory into the 'downloads' section??

Archive.org has a copy of "Practical Treatise on Milling and Milling Machines", so I just downloaded it - thanks pointing that out - I had only read exerpts from that book a few years ago. Time I read the whole thing.

 

[benmychree]

I have the book that I bought as a reference for my apprentice classes, all those years ago (1964), it was getting pretty shabby with the covers coming off, not to mention smudgy pages, especially the tables on dividing, a friend who does bookbinding rebound it for me now in hard cover, I also have several other copies of it of various dates.

 

[vocatexas]

I'll try to get some photos posted tomorrow night of what I have. I know I'm missing the two banjos. I may be missing the idler gear as well. I've got a box full of change gears, though. I'd really like to have all the parts so I can try helical milling at some point. There were a couple of shafts and damaged gears in the box of tooling as well. I think the dividing head has been damaged at some point and some parts replaced. I haven't worked up the courage to take it apart and inspect the internals yet. I'll have to watch Keith's video a couple more times. LOL

 

[benmychree]

I am looking to cut a helical gear presently, I got all the gears out of the compartment at the base of the machine, and found there are two 24T gears, so add one more to my total, so make that 11 gears in the standard set, plus the 24T idler gear.