Can Anyone Make Bevel Gears?

Who here has a gear making machine?

Looking for a shop that can make a set of spiral bevel gears. The current gears are straight bevel gears but want to replace them with spiral to smooth out the drive. This is for the table drive on the Gray PM. I have prints of the gears and can email the PDF to anyone interested.

Gear 1:
9.666 pitch diameter
29 tooth 3 pitch
20 degree pressure angle
material 3140

Gear 2:
5.666 pitch diameter
17 tooth 3 pitch
20 degree pressure angle
material 4140

We can supply the rough machined blanks and also take care of the heat treating.

Here is the 5 page PDF file. The bevels are pagfes 1 and 2. This site will allow a maximum of 100 downloads for the next 7 days.

Download PDF

I would contact Martin Spocket & Gear in Scottdale, GA (might have to go thru Applied Industrial Technologies, not sure).

They have made all kinds of "MTO" (made-to-order) sprockets and gears for me and I'm always impressed by their low costs and fast turnaround.


Aside: What's up with that old lathe in Kentucky (??) some of us donated money towards the retrieval of....???

Yep Rick:

I could use my $50 if moving the big lathe is not happening in the forseeable future.

John

Rick
Call Stahl Gear in Cleveland
440-431-2820 ask for Joe Bronstein
They can make bevel gears over 50"

PS. I will be outta town from the 30th to the 9th so I'll just store your hoist till I get back.
Scott

You can also try Moore Gear manufacturing company at
573-486-5415

I know they have CNC and manual machines for making gears and should be able to get this done for you.

Bobby

One-off sprial bevel gears are hideously expensive. It's an 8 hour job just to perform the calculations and set the machine up. It's additional if they have to make arbors. Then you have to pay for tooling - the share of the cutter price they have to sharpen back. Or you might have to pay for a new rougher and finisher. There's there's heat-treating and finishing. I think that $5000 is the low end for a gear pair like you want.

If that straight cut gear set is noisy or cogging it's either worn-out or not set up correctly. Flushing the back angles of a bevel gear pair does not constitute a good set up. The gears have to be blued for a central toe bearing and all the other details covered by the excellent Gleason bevel gear manual.

The tooth numbers tell me that gear pair is high performance; they don't make gears in prime number pairs unless they're following the Buckingham design protocol for high performancs or precision drives.

Good luck on the spiral bevel gear pair. Unless you can find factory parts, a commecially available pair that's close, or reconcile a straight bevel gear pair as a replacement you'd do better to see if you can tune up the existing gears.

Couple things to look for. Foreign object or material damage, evidence of running dry, odd wear patterns, cratering at the pitch line. If none of these are present chances are you can re-set the existing gears to eliminate you problem.

Rick Rowlands,
Not to rain on your parade, but further to Forrest's post:

Spiral bevel blanks have different face & root angles than straight or Zerol bevel gears.
As For the calc's it's called a "machine summary" this has to be done first before the drawing change, because this is where the numbers come from.

The straight gear cutters are relatively simple compared to Zerol & spiral cutters.
Three Diametral Pitch cutters are probably going to be 12.00" Diameter heads so, if the gear shop has the cutter heads (about $8,000.00 each 1990's) the blade and shim sets, one for the gear & two sets for the pinion say $6,000.00 a set, used to be 12 weeks delivery, You are all ready into a big number.

Machine tooling, nose arbor for each part both for the cutting machine and the test machine, these are some moderately big parts so the arbors are going to be big too, cutting machine needs custom draw rods for the hydraulic chucking system on "Gleason" machines.

Now you go to heat treat and you hope the gear house engineer has enough experience to accurately guesstimate how the spiral is going to unwind, so that your gears finish up with the correct contact pattern. Drwg difficult to read, is that Rc 30? If so I would have rough blanked, NQ&T to Rc 30, finished machined & then finished cut the gear teeth.

I had many one off quotes & did not see the customer proceed, some that did I ground the parts from the solid, takes a while grinding, but you did save overall for one or two parts versus the cutter cost, you still have arbor costs, also gear house will probably need at least one set of parts for setup & development, usually do not need for straights.

I wish you well in your endeavor,

Les H.

hpc gears mite quote you on them but its going to hurt the old wallet

why couldnt a machining center with a rotary axis just ball end mill it out of solid?

maybe half hard 4140?

it's just one gear set.

????

The lathe is still down in Kentucky and basically the ball is in Tommy Turner's court now. He was supposed to be having a large machine delivered and he was going to see if the trucker would take the lathe on up to me. Haven't heard anything recently on that.

I would be willing to refund everyone's contribution and let Tommy find another home for it if that is the consensus of the STOIC membership. Moving the lathe is going to be a stretch for my tight budget and perhaps it would be better for me to concentrate on some of my other projects.

As for the gears I'll have the owner of the planer mill read this thread. Perhaps it will change his plans for replacing the gears. He already got a quote of 20k to replace the gears in kind. We were thingking that was way high but after reading the posts perhaps it isn't too far out of line.

I would be willing to refund everyone's contribution

Click to expand...

Plainly the right thing to do Rick, IMHO

John

Rick,

Option buy these if you can locate them.



make sure you get the change gear cabinate & cutter gages that came with the machine originaly
then you can cut your own!

Cheers Les H.

I am a factory, not a machine shop, so I could be way out of line here. I constantly get faxes from this company: RUSH GEARS

That Rush Gears outfit has to be the epitome of industrial spammers. They can fix you right up with a spur gear most anyone could cut in a mill, with 24 hour shipment for just $5000 or so, and no, I didn't put more zeros in that price than intended. Hard to imagine who it is they actually sell anything to.

Jason, Rush seems to be a good outfit but I had the same sticker shock on gears as others mentioned when I wanted a quote from them. In my case I wanted to buy 3 simple spur gears just a disk with teeth or so I thought. They could have been almost any old metal just something better then plastic, I didn't need hardening and I was shocked at the price. Turns out they needed to make all sorts of special tooling and the likes. I'd have thought that in this day and age making spur gears in small quantity would have been far cheaper. I guess I'd imagine a CNC vertical shaper with a disk mounted on a arbor. Punch in the gears specs and a computer could generate tool path. I could imagine a factory stocking a given # of blanks in house with holes in them and a holding jig that would be kind of one size fits all. Then Plop the disk on the jig and hit go sounded fine to me but the guy on the phone said it was more complicated then that though.

Oh well with horizontals costing what they do and an indexer being a nifty tool to have around the shop one day it should be an educational fun little project. Perhaps this would make a nice little buisness for some one if my idea would work. In my case there was like a $1500 charge per gear with a minimum order of 2 with prices steadily dropping after that.

Adam

Depending on the use making gears can be easy. I needed 2 30 tooth gears ~1.3 OD for the maximat standard. I had never cut gears before but figured why not give it a try. After cleaning up the dividing head found under the lathe at school and shaping a HSS 3/8 tool bit by eye with the old gears I shaped the new gears from High density polyethilene using the old Bridgeport. These gears are have held up well even though I think that material is a little too soft.

Setting up Offset bevel spiral gears is not easy. as the backlash and pinion depth are related and often confusing to read in the contact pattern. Also the straight Bevel gear you showed in the PDF will result in little to no axial load on the pinion gear. While a spiral Bevel gear may result in considerable axial load on the pinion gear this may require redesign of the bearings and or threads in the end of the pinion. If your client is set on this type of gear perhapse a change to a standard automotive rear end gear set may be in order. Though a 17:29 ratio would be rare to say the least.

Glad I never had to use rush gears services. They do however waste a serious amount of my fax paper though. Sorry it is of no help.....

Jason

Way back in the day, in 1985 I setup some Gleasons for a few jobs, what amazing machines, like little sewing machines that make bevel gears


Bill

Thats where the 20k quote came from. Rush Gear.

For 20K I'll whittle them out of a solid with a file!