Indexing/Dividing Heads

Looks too large for a mini-mill. It is a pretty looking tool, but the table you have is probably sufficient. Learn to use that, and

*then* worry about the dividing head -- and a larger mill to use it.

Good Luck, DoN.

If your gears have tooth counts that divide evenly into 360, (spacing comes out to integer values for angle in degrees), you can use a spin- index fixture. These fixtures are inexpensive and small enough to work comfortably on a small mill. You would need a 5C collet (or set of collets) to hold your work piece. I've cut gears using a spin- index, and have cut a 32 tooth spline using a rotary table identical to the one shown in your first link. To index the 32-tooth spline (11.25 degree tooth spacing) I had to use the dividing plate to accurately set and hold the positions. I bought the dividing plate set when I bought my rotary table, and if you don't have them, you might try to buy them from the same place where you bought your table. There are two easy ways to mount your workpiece on the rotary table. The first is to use an M2 end-mill holder (which you probably already have) mounted in the center hole of the table, and making an arbor to mate the gear blank to the holder. The second is to buy a small three-jaw chuck with an M2 stub to be mounted in the center hole. These chucks, with M2 mounting stub, can be bought on eBay for under 50 bucks, and make it easy and quick to mount all sorts of pieces on your rotary table. Pat

============= First thing I suggest is to get the book _Gears and Gear Cutting_ by Law.

will be helpful, even if you have a mill.

If you are going to make home made cutters from lathe tool bits, you will need a tool holer like a fly cutter except the bit is at right angles to the holder axis. If you have a MT spindle the Little Machine shop has blanks that you can adapt.

?ProductID=2393&category=also see their dividing heads is commercial side of LMS ?ProductID=3900-2401 Enco and WTTools may give you a better price [check with group for discount codes and free shipping offers].

?PMAKA=200-1096&PMPXNO=952279&PARTPG=INLMK3 Be reminded that you will need a special plate with 127 holes to cut a 127 tooth [metric change] gear.

If you are going to hand grind your cutters a die grinder or HD dremel tool is very helpful.

also see Good luck, and let the group know how you make out, and what the gears are for.

-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).

Here is an example:

miscut tooth at the top is full thickness for most of its width, which the photo doesn't show. I forgot to lock the index spindle.

The mill is a Clausing, 50+ year old American iron with about the same work envelope as a Sieg or mill-drill. The index is a no-name POS.

That 20PA gear tooth cutter and the one for the motorcycle sprocket (below) were ground to shape on a surface grinder, which I presume you don't have. This is a fixture I made to fit a cutter to a 30PA involute tooth shape by hand:

I used the partly formed bit to rough out the blank before grinding it to final shape, to minimize difficult resharpening.

jsw

table:

>

this:

>

Yes. He already has the rotary table, FWIW.

He also has a set of 5C collets.

His came with the dividing plate set, so that is no problem.

He also got the matching tailstock as part of the rotary table set, so (if his table is big enough on his mini-mill) he could also mount the gear blank on an arbor between centers, which is probably the best way.

The primary place where the dividing head he was looking at would win is for tooth counts which are not available from the worm ratio and the dividing plates (such as the 127 tooth gear mostly used for metric/inch thread conversions) since it appears to be capable of differential dividing.

It is also quite heavy, and I think that the best place for it is on a mill or Bridgeport size or larger.

Enjoy, DoN.

You would need a 5C collet (or set

=A0 I've cut gears using a spin-

564

====== Another useful technique is to use a slitting saw to remove most of the material. For some examples see below -- most any good mill supply should carry.

?RequestData=CA_Search&navPath=All+Products%2F%2F%2F%2FMachine+Tool+Accessories%2F%2F%2F%2FArbors%2F%2F%2F%2FSlitting+Saw+Arbors&eaprodid=92848-99-007-060 If you have a #2MT or #3MT spindle in your mill LMS has collets and/or end mill holders to fit. Will also fit your dividing head if 2MT [some are B&S] B&S see If you want to make your own saw arbors see Be sure and let the group know how you make out.

-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).

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O.K. Plenty of choices then.

Hmm ... helical and bevel gears will be more likely to require the dividing head. And for helical, you also will want a way to gear the X-axis leadscrew to the index head so you can rotate the gear blank as you feed. And ideally, you also want a universal mill (the table can be set at an angle to its normal position). This is probably beyond the capabilities of your mini-mill.

O.K. The B&S taper is fairly common on dividing heads, but it means yet another taper to keep around.

And you will want to fit it with keys to match the slots on your table. How long is the total length of the slots BTW? You've got 6.25" length on the head in horizontal position, perhaps 5" length on the tailstock, and typical arbor between centers will be 6" or so, so this means that you will need at least 17.25" total slot length in the table to work between centers unless you can find or make some shorter arbors.

I also don't see a center for the indexing head listed (which would have to be a B&S 7 taper. And you can't use just a plain center like for a lathe. Centers for a dividing head need either a T-bar across just behind the point, (or at least a half T) to serve as a drive for the dog which connects to the arbor when working between centers. And it needs to have a slot in the end (or ends) of the bar, with a screw to clamp down on the tail of the dog so it does not shift.

Well ... what is the table slot length? And if it is shorter than 18", then what are the odds that you will later get a larger mill?

If you can use it on your current mill -- or can get a larger mill to fit it -- and the price is good enough, go for it. I had been thinking that you wanted to purchase a new one.

Note that there is a nice trick for making a ball on the end of a shaft using a dividing head set at an angle (perhaps tilted up 45 degrees or so) and a boring head with the cutter turned inward instead of outward. But this needs a lot of room between the table and the mill spindle -- and it needs a 3-jaw chuck which will screw onto the spindle of the dividing head. I don't see one listed in the "comes with", and I don't see anything saying what the spindle nose thread is on the dividing head -- which would have to match the backplate of the chuck.

BTW -- I see the slots for the keys on the bottom of the tailstock ("Tailstock3") but no keys. You will have to make keys which fit the slots on one side and which fit the mill's bed slots on the other side.

For some of the gears you want to make, I think that you will be better off with a gear hobbing machine -- but that will be very heavy and very large -- and not too easy to find. Plus, you need a special hob (gear cutter) for each gear tooth pitch -- though you won't need the set of eight for each pitch to cut all tooth counts -- one hob will do it all for a given tooth pitch.

Good Luck, DoN.

Yes, it is.

It would have been worth it if I could use a dividing head.

The entire length of the table itself is 15-5/8". :-)

390204979900

Not any time in the near future, unless I win the lottery. But since I don't play the lottery...

The two parallel raised flats in the center of the table are about

13-3/16" long.

Nope. Cheap is the operative word with me. :-)

Well, obviously one cannot use a dividing head with a mini mill/drill, unless there are special "small" sizes of dividing heads made somewhere.

That will have to be my first project after I get the machine working. I just need to find reference material to study. Or if I'm lucky I can find some keys that fit the tailstock but with enough on them to mill down for the table.

Bevel and Helical gears will obviously have to be purchased from some company like "small parts". In the meantime I'm forced to concentrate just on what I can do with my rotary table.

Thanks.

Darren Harris Staten Island, New York.

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Which requires a larger mill than what you have, based on what follows.

You could conceivably make shorter arbors, but then the taper becomes more of a problem.

O.K. Yes, it does have a threaded spindle nose -- covered (and protected) by the black ring behind the chuck.

:-)

Too sort -- and only one T-slot (the area between the two "raised flats"). If you look at the ends of those flats, you will see that they are undercut along the center line -- but not on the outside areas, because there is no change in width where it comes in line with the raised flats.

[ ... ]

Not unless you make one -- a bit of a project. But you might be able to do this with an angle plate under the rotary table to give it a

45 degree angle or so. [ ... ]

O.K. Just measure what is wider -- the slot in the center of the mill's table or the groove in the bottom of the rotary table. Mill up some material just barely the wider of the two and long enough to make two keys plus a bit. Then mount it in the mill vise (which I also don't see in the photos of the mill). First adjust the vise so the stationary jaw is parallel to the motion of the table. Then mount the key blank in the vise, supporting it by parallels the right width so you can access both sides to the depth necessary to make the sides the same depth as (or a little deeper than) the groove on the bottom of the rotary table -- or the vise -- or the dividing head -- or whatever you are making keys for. And mill that portion to fit the mill's T- slot Then cut it in two to make two keys.

If the mill's T-slot is wider than the key slot in the bottom of the device in question -- make to the mill's width first and narrow the one area to fit the key slot. In this case, you can mill down a bit deeper.

Once they are made -- you will need to drill through them for screws to mount to the key to the device, and counterbore to swallow the head of the screw.

The purpose of the keys is to make it go onto the mill precisely the same way each time. Useful for the angle readings on the rotary table, or for a vise's fixed jaw being parallel to the table travel so you don't have to indicate it in every time you install it. And for a dividing head -- to make the spindle parallel to the X axis, and the tailstock precisely on the same line.

BTW -- looking at the photos of the mill -- you should get some fine steel wool or fine ScotchBrite (not the kitchen cleaning kind) and a bit of a light oil (maybe a penetrating oil) and clean off the rust which is forming -- then rub the surfaces down with Vactra No. 2 to keep new rust from forming.

Good Luck, DoN.

But I don't think that would help me a whole lot with making more than one kind of bevel gears.(Or Helical gears). In my mind I've been working on some ideas though and may be onto something.(Too bad our patent system is useless for the little guy). :- (

I've copied the above to a special text pad for later.

I do want to say however that my table appears to have three T-slots. Those two raised flats in the center are "T" shaped from one end to the other. And the outside flats of the table have spaces under the inside making a total of three slots. If the ASCII comes out correctly, you would be looking at the table from the end. ___ _____ _____ ___ | _| |_ _| |_ _| |_ | | |______| |______| |______| |

Thanks. I recently brought it up from the basement.

I'll use WD40 to clean iot up and then the Vactra #2 I just got via eBay.

Thanks.

Darren Harris Staten Island, New York.

But I don't think that would help me a whole lot with making more than one kind of bevel gears.(Or Helical gears). In my mind I've been working on some ideas though and may be onto something.(Too bad our patent system is useless for the little guy). :- (

I've copied the above to a special text pad for later.

I do want to say however that my table appears to have three T-slots. Those two raised flats in the center are "T" shaped from one end to the other. And the outside flats of the table have spaces under the inside making a total of three slots. If the ASCII comes out correctly, you would be looking at the table from the end. ___ _____ _____ ___ | _| |_ _| |_ _| |_ | | |______| |______| |______| |

Thanks. I recently brought it up from the basement.

I'll use WD40 to clean iot up and then the Vactra #2 I just got via eBay.

Thanks.

Darren Harris Staten Island, New York.

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But I don't think that would help me a whole lot with making more than one kind of bevel gears.(Or Helical gears). In my mind I've been working on some ideas though and may be onto something.(Too bad our patent system is useless for the little guy). :- (

- Hide quoted text -

- Show quoted text -

I've copied the above to a special text pad for later.

I do want to say however that my table appears to have three T-slots. Those two raised flats in the center are "T" shaped from one end to the other. And the outside flats of the table have spaces under the inside making a total of three slots. If the ASCII comes out correctly, you would be looking at the table from the end. ___ _____ _____ ___ | _| |_ _| |_ _| |_ | | |_____| |_____| |_____| |

Thanks. I recently brought it up from the basement.

I'll use WD40 to clean iot up and then the Vactra #2 I just got via eBay.

Thanks.

Darren Harris Staten Island, New York.

- Hide quoted text -

- Show quoted text -

- Hide quoted text -

- Show quoted text -

But I don't think that would help me a whole lot with making more than one kind of bevel gears.(Or Helical gears). In my mind I've been working on some ideas though and may be onto something.(Too bad our patent system is useless for the little guy). :- (

- Hide quoted text -

- Show quoted text -

- Hide quoted text -

- Show quoted text -

I've copied the above to a special text pad for later.

I do want to say however that my table appears to have three T-slots. Those two raised flats in the center are "T" shaped from one end to the other. And the outside flats of the table have spaces under the inside making a total of three slots. I couldn't get the ASCII working properly so here is a diagram I drew.

Thanks. I recently brought it up from the basement.

I'll use WD40 to clean it up and then the Vactra #2 I just got via eBay.

Thanks.

Darren Harris Staten Island, New York.

I was not talking about making gears here. I was telling you how you could possibly use your rotary table, a boring head, and the mill to make a ball end to a shaft. (You would have to finish the end away from the handle with a file however, because it does not continue the curve down into the area opposite the shaft.

It helps to work for the government. I have three patents acquired when I was working for an Army R&D lab. Not that they were for things likely to be commercially viable -- but the patents did not cost me a cent -- and the government has the right to make the devices royalty free. :-) (No -- they weren't mechanical devices -- electo-optical ones. :-)

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O.K. The reason that I did not think that you had three T-slots was the lack of a stepback on the sides lined up with the ends of the center parts. So -- you would have to put the T-nut in the end recess, slide it forward or back (to get under the ledge for the front or back T-slot), and then slide it into the slot.

Good Luck, DoN.

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Actually -- the ASCII drawing looked fine on my system. Yours may have been displaying it with a proportional space font, even if you created it with a fixed space font. Try setting your newsreader to Courier to get a fixed space font.

And the web link shows precisely the same thing that I got from the ASCII.

I've already replied to the rest of this -- one of four copies which showed up yesterday, plus today's copy with the URL instead of the ASCII drawing.

Enjoy, DoN.

Ok. The reason for that is because I don't have a news reader. I view and post via Google Groups. And Google Groups has a delete option which I used when the ASCII didn't show up right.

When you post ASCII it won't show right either, until I copy it and paste it into a text document. And when I create ASCII in the same text document, and attempt to post to the Google "rec.crafts.metalworking" newsgroup, it will not show up correctly.

Thanks.

Darren Harris Staten Island, New York.

Why the hell not? I pay about $4 a month for newsgroups from Giganews and simply changed my settings in my old copy of Forte Agent 1.93

Best newsreader out there.

Service is great too!

Gunner

One could not be a successful Leftwinger without realizing that, in contrast to the popular conception supported by newspapers and mothers of Leftwingers, a goodly number of Leftwingers are not only narrow-minded and dull, but also just stupid. Gunner Asch

I don't pay nuttin... :-)

Darren Harris Staten Island, New York.