Gear question

Suggest buy them instead--Sterling ( stock drive products ) should have whatever you need reasonably priced although you might have to machine out the bore and press in a new hub.

1. You are going to be cutting aluminum. M2 ought to be fine.
2. and 4. You can use either, but I would look on Ebay to see if you can get a gear cutter that you can use. I did a search on Ebay for gear cutter and found 400 items.

Note you may not find a gear cutter that will work to cut gears that are compatible with your existing gears. But so what. You can make gears to replace your existing gears. You just need a complete set of gears. They do not have to be 1.0 Module.

1. I would use the cheaper alloy. If any of the gears fail you can make another one.
2. and 6 I have no idea.

1. Module 1.0 gear cutters can be found by searching on the internet. I suspect one could use a 24 or 26 DP gear cutter and cut gears that would work with Module 1.0 gears. But surely someone that actually knows something about cutting gears will chime in here. ( Unless they have all quit reading RCM because of all the OT posts ).

Dan

George, I'm really confused. I cannot see you making any gears with the equipment you have. I think you will find it an exercise in frustration. Gears of any description are not easy to make. Good gears require the proper equipment. I never make parts that I can buy. Buying is almost always cheaper. If you are doing this as a hobby, I suggest you have far too much time on your hands. Steve

have. I think you will find it an exercise in

the proper equipment. I never make parts that I can

suggest you have far too much time on your hands.

Blink blink...even I..a fumble fingered service tech, have made gears on my home hobby shop machinery....

Some..some gears are hard to make. Others are rather easy.

Gunner, pondering on the ways of making a 40" diameter x 10" wide herringbone gear....and not finding any

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have. I think you will find it an exercise in

the proper equipment. I never make parts that I can

suggest you have far too much time on your hands.

========== Indeed, but I am retired and have far more time than money. Blue Ridge sell the EMCO gears, but apparently these are made from solid gold. Stock gears are a little less expensive, apparently made from sold silver, and will require considerable rework including filing a keyway after opening up the bore and cutting back the boss/hub. I have already made several functional gears using a hand ground

3/16 square form tool in a boring bar and a spindex, but the number of teeth possible is limited. I have acquired an inexpensive dividing head, and now want to finish not only the "factory" set, but also some additional sizes, possibly including metric change gears. Even if there is not room for a 127 tooth gear, some compound ratios come close [enough] to 1.27.

The good news is that after considerable internet search I have located a supplier of metric/modular gear cutters. They can provide both the B&S style (like a slitting saw), and end-mills formed to the involute profile, which appears to be ideal for my particular set-up. The bad news is that they are located in India, but will sell at retail, and ship international air parcel post. Given that these end-mill profile cutters are about like 3/8 or 1/2 end mills, and I have both MT Weldon adapters and ER25 collets to fit, this seems the most likely solution.

The supplier is

they supply apparently all of the various styles of gear cutters, pressure angles, PD/Modules, etc. [I don't know about cycloid in addition to involute profiles.]

Email contact for these products is snipped-for-privacy@gmail.com Att: Sri Vishal Kapoor {Tell him George McDuffee sent you}

Truth in posting disclaimer: I have not yet done business with this company.

Note to Gunner: This may be one way to machine your special gear if you can stand a space down the center for tool overrun, but it will be a king size PITA to set up and where do you get the blank? Would ZA-27 [zinc alloy about as strong as a good grade cast iron] be acceptable? Might be a good lost foam project. Any of our foundry people want to try? How much does this gear weigh?

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-- 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).

Since you need several sizes of the same pitch, maybe the one-time overhead of making a hob would work for you:

You could cut the gear teeth close to final shape at the pressure angles with a slotting cutter to help the hob self-center and stay sharp longer.

jsw

Make two helical gears 5" wide with opposite angled teeth and bolt them together.

That depends on what other (non-powered) tools he may have.

There is the pride of accomplishment to consider.

And looking at the second URL this being done by student machinists as part of their learning process.

Interestingly enough -- there is something about this web page which crashes Opera -- though Mozilla Firefox shows it with no problem

-- just too small a font for my current eyes. :-)

This suggests that other tools are available.

Blending the various radii might be a bit tricky. I have a surface grinder, but not a radius dressing tool.

Cartoon? Where?

The lathe can be used for turning the gear blanks. The milling head could be used for a form cutter in an appropriate holder, or the shaper could be used with the form cutter -- but the problem with the shaper is getting a consistent depth of cut.

But for either, you need a dividing head or perhaps a rotary table with dividing plates. The problem may be getting one small enough to fit either machine. I've got a Rockwell/Delta 7" shaper and know how difficult it is to fit extra tooling like dividing heads onto it.

You should have asked this *after* mentioning the material. Given that you are going for aluminum, I think that even the M2 will suffice.

Which one can you fit your dividing head or rotary table onto in an orientation which allows access to the work area of the gear to be?

Personally, I would consider the milling head on the lathe (really, don't just call it a lathe when you are intending to use the milling head) with a selection of involute gear tooth milling cutters on an arbor. (Check which ones you will need for the tooth counts which you are making. You don't mention which tooth counts you will need to make -- but if the counts are widely separated enough, you will need a different cutter (either the milling cutter or the form cutter) for each tooth count.

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No guess here. How fast will the teeth wear and deposit on the meshing teeth? One thing to bear in mind is that you absolutely *don't* want two aluminum gears meshing -- alternate between steel or cast iron and the aluminum. Aluminum on aluminum will gall badly leading to a

*very* short life for the gears.

I seriously doubt that they are.

Not I.

Probably more than the cost of involute gear tooth cutters bought as milling cutters.

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Highly unlikely. No commercial use. Commercial shops who

*have* to make gears instead of purchasing them (because they have some kind of unusual feature) and don't have the production quantities needed to justify a gear hobber would be purchasing the involute gear tooth cutters (likely a full set of eight with spares for the most commonly used sizes) and certainly not single-point form tools. The production rate difference would be too much of a penalty for the form tools.

Personally, as a hobbist, for gears which I need to make (or repair), I have purchased the gear tooth mills -- and I have a horizontal spindle milling machine so there is sufficient rigidity to drive them well.

Hmm ... another possibility with the shaper. Simply grind a rack form tooth (no involute shape needed), and set up the gear blank so it is rotated as the cutter steps across the blank, so it is turning and producing the true involute shape as it passes. You will need to sit and wait as it passes through a single tooth fully before resetting the blanks to cut the next tooth. It will take *lots* of time, but you will get the right gear tooth shape with a simple to produce tool. Something like an Acme threading tool if cutting 14-1/2 degree pressure angle, or somewhat more blunt if cutting a 20 degree pressure angle. The real trick is setting up the mechanism to rotate the blank at just the right speed as you step through the tooth position. I think that this would be done with a drum with a steel cable running around it with the cable's centerline at precisely the pitch diameter.

Good Luck, DoN.

Strange -- how about the other pages on the site? Nothing fancy and no special features on any of them, just box stock M/S Front Page 2000. All pages work fine with both FireFox [v 3.6.6 latest download] and M/S Exploder on my computer.

will allow you to adjust the font size. Font at 100% is about right on my monitor.

Upper right hand corner of the spreadsheet. Shows in both M/S excel and Open Office spreadsheet for me.

also see

I also have a B&D RTX electric die grinder. Some sketches indicate that it may be possible to mount this grinder in a frame to generate the two radii on both sides of the tool. I have some small mounted stones and a set of the diamond pins from HF and these allow very easy freehand grinding of hook and chip breakers in 1/4 square HSS. Also ground up a "bullnose" finishing tool with considerable hook for the shaper using a 7/16 M2 blank. Worked fine and gave a very nice finish.

I was expecting to rig a positive stop for the shaper down feed. Further consideration indicates that I will most likely do all the operations in the mill mode on the Emco including rounding the blank and thinning the outside edges of the gear to 9m/m. The dividing head can be mounted vertical or horizontal and used as a rotary table. LMS [Little Machine Shop] had some blank 2MT arbors with 1" diameter heads. I plan on modifying one of these to use as an arbor in the dividing head to mount the gear blanks.

The dividing head I purchased will just fit on the Emco, and the Atlas 7B will require a table extension to support the dividing head, and a "short" tool post to clear everything.

Being a real cheapscrew, I generally get the sale stuff from Enco, but even this is getting expensive.

The dividing head just fits the Emco, so this looks like the better option. Could fit the shaper, but will need to rig up a table extension.

#2 [55-134 T] and #3 [34-54 T] cutters will cover the range of interest. { FWIW -- while it may be a typo on some of the foreign sites, it appears their cutter numbers are "backwards" to U.S. usage} I managed to locate a 2MT arbor with drawbar that is the correct size for the 1.0 module B&S style cutters [apparently 16 mm hole as these are all imports], but from a UK supplier. As indicated in an other post in this thread, I also located a source in India that makes gear cutters like an end-mill. Downside is the difficulty in sharpening compared to the form ground B&S style, but I already have both Weldon endmill adapters and ER25 collets for 3/8 and 1/2 shank endmills.

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Thanks for the reminder. The aluminum gears worked well with the CI gears, but most likely would not be satisfactory with another aluminum gear. That leaves 11L44 and sheet plastic such as nylon.

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I was thinking of the home/hobby machinist, and possibly the "one-off" repair shops where parts are no longer available.

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Indeed. See

I considered this but the effort required to construct the indexer/rotator and rig the shaper seems very high. I could see this for the hobbiest that makes lots of gears in strange sizes and profiles, e.g. cycloid. This looks like an interesting project for CNC that would rotate the dividing head so many "clicks" for each stroke of the ram, assuming fine automatic feed. Easy to change the number of "clicks" for changes in diameter/tooth count.

Thanks for the feedback.

Similar to above I recall as being called using a "pitch block", and though generally it's used for gear grinding I see no reason why a single hss tool blank having a rack form couldn't be used in a planer / shaper instead....

We had used a round chunk of aluminum and a couple pieces of steel banding...and I can't remember exactly how the arc was swung in relation to the wheel stroke axis or even how the gear was indexed for each tooth but pretty sure the wheel was dressed to a rack geometry and had perhaps 5 "teeth"