Are these bevel gears worn too badly to re-use?

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 25, 2017

• #1

For 25 years I have used the same 3:1 bevel gears and a stainless-steel flexible shaft to turn the propeller on my human-powered catamaran. Yesterday I replaced the flexible shaft assembly but today the gears became noisy, started to bind, and then seized up completely. Are these gears too worn to re-use? Could they be causing the binding? The crown gear looks o.k. to me but the pinion has a lot of wear.

Please look at the attached pictures and give me your thoughts. Thanks.

 

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Last edited: Jul 25, 2017

L

L Vanice

Diamond

Joined

Feb 8, 2006

Location

Fort Wayne, IN

• Jul 25, 2017

• #2

Amazon sells Boston gears. If they have that size pinion, it would be a good idea to get a new one.

Hope you need this size because it is only $9.51 right now. Boston Gear PA45312Y-P Bevel Pinion Gear, 3:1 Ratio, .5" Bore, 12 Pitch, 18 Teeth, 2 Degree Pressure Angle, Straight Bevel, Steel: Amazon.com: Industrial & Scientific

Larry

 

bcstractor

Titanium

Joined

Apr 25, 2004

Location

Monument CO USA

• Jul 25, 2017

• #3

If you cleaned them up with a small Swiss file they might work Ok but it looks as though they were short on lubricant.

 

T

tdmidget

Diamond

Joined

Aug 13, 2005

Location

Tucson AZ

• Jul 25, 2017

• #4

What pictures?

 

sfriedberg

Diamond

Joined

Oct 14, 2010

Location

Oregon, USA

• Jul 25, 2017

• #5

I'd say that pinion is toast, although nothing would stop you from using it in an emergency. It also looks like the other gear (call it "face") was set on its shaft too far toward the pinion; there are pretty clear signs that the tips of the face gear teeth were grinding into the body of the pinion. In fact, if the noise and jamming started abruptly, I'd suspect the face gear shifted position (loose setscrew, perhaps) or whatever it's ultimately mounted to shifted toward the pinion centerline.

 

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 26, 2017

• #6

Thanks Larry. That's a great price at Amazon. I just checked the gears. They are actually 4:1 Browning YSB10B60-40 and 15-40.

 

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 26, 2017

• #7

Thanks, I'll get a file tomorrow and try that. I cleaned the lubricant off for the photos. I wish I knew how to post the bigger sized photos that people are using here.

 

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 26, 2017

• #8

Sorry. I accidentally deleted them all while I was trying to make the pictures bigger.

 

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 26, 2017

• #9

Thanks sfriedberg. Right now I can't use the drive at all, the binding makes it too hard to pedal. It's weird because before I changed the flex drive it worked fine. There is a factory-made 1/2" stainless-steel solid shaft fastened to one end of the flex cable. It extends through a bronze bushing, then the pinion gear is attached to it (to meet the crown gear that is mounted on the pedal axle). The old stainless solid shaft was 5/8" OD but the factory made the new one 1/2" OD by mistake so we simply bushed down the old 5/8" ID bushing to 1/2". Maybe the 1/2" bushing isn't strong enough to prevent all deflection. I can't see any, but I'm not sure. Could the gear wear alone cause enough binding to completely seize up the gears?

 

M

muckalee

Cast Iron

Joined

Jul 17, 2011

Location

Americus, Georgia

• Jul 26, 2017

• #10

No, look at the recent changes for the binding source.

 

Mechanola

Stainless

Joined

Mar 21, 2011

Location

Äsch

• Jul 26, 2017

• #11

I vote for replacement. These wheels are beyond form tolerance. The rolling action of one tooth over the other isn’t there anymore.

 

MrStretch

Hot Rolled

Joined

Mar 20, 2017

• Jul 26, 2017

• #12

Changing the gears without first finding the source of the trouble will only lead to wasted money & frustration. They might need to be replaced eventually, but the changes you made are causing the problem somehow. You Def want to figure that out first.

 

H

HuFlungDung

Diamond

Joined

Jan 19, 2005

Location

Canada

• Jul 26, 2017

• #13

Gears don't seize up, but you can jam two tapered gears together far enough that they'll be in a negative backlash state, I guess you might call that seized, but I wouldn't. Seized is something that has welded itself together and become inseperable.

 

A

adama

Diamond

Joined

Dec 28, 2004

Location

uk

• Jul 26, 2017

• #14

Bevel gears are real intolerant of setting errors, takes very little error to make em wear fast or jam up.

 

Gordon Heaton

Titanium

Joined

Feb 19, 2007

Location

St. George, Utah

• Jul 26, 2017

• #15

I think adama is probably spot-on. Are you sure somebody didn't try to compensate for wear by seating the gears a bit closer? (it doesn't work, and often causes a problem similar to what you described). As far as usable goes, those gears might have a lot of life left for a human powered device.

 

C

Clive603

Titanium

Joined

Aug 2, 2008

Location

Sussex, England

• Jul 26, 2017

• #16

Seen similar before. Well worn bevels apparently still working satisfactorily when in place but impossible to get going again when re-assembling after inspection. Logically it ought to be possible to get them back exactly where they came form but in practice nope.

Clive

 

C

cdnInventor

Plastic

Joined

Jul 25, 2017

• Jul 27, 2017

• #17

Thanks muckalee. During the recent changes, 2 set screws were added to hold the pinion gear in place (previously a spring pin held the pinion in place, so we tapped the old holes). Upon a complete disassembly, it was obvious from the scoring on the axle that the set screws had let go.

Thanks to everyone else who replied. Your comments have been very helpful. This forum is fabulous.