Bevel + Mitre Gears

Whats the difference between the two?
I'm considering using bevel gears (mitre?) to drive the governor on a small
stationary steam engine. The drive would be 2:1 from the crankshaft then
1:1 to drive the governor. The crankshaft is 7/16inch and the flywheel is
7-1/2 inch diameter. The governor driveshaft can be chosen to suit,
probably 3/16.
Two challenges are to get the large gear on the crankshaft in proportion to
the flywheel and to find a supplier who want less than £20 a piece + VAT
+P&P which makes the thing not doable. RS don't have what I'm looking for
and HPC looks like well into £100 for the four. EN8 or equivalent would be
fine. Bronze gears would be great but I dread to think what the cost
wouldbe.
Any suggestions?
Steve
Reply to
Steve
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If you could change the ratios around and have 2:1 at the governor then th egears that I bought for my traction engine governor will do, brass with 1/4" bor to the large wheel, 3/16" in the small but you could solder in a bush. All for about £20 the pair. If they suit I will post details.
Jason
Reply to
jasonballamy
Why not make your own? Peter
Reply to
petercolman45
Don't know about prices, I've not used them for a while, but SH Muffett were helpful a few years ago.
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Richard
Reply to
Richard Shute
Why not make your own? Peter
Looks too dificult - I have a mill and decent rotary table, so plain spur gears I can do, but bevel gears look beyond beyond me.
Reply to
Steve
Wise decision. Proper bevel gears cannot be milled as the tooth pitch is not constant.
Reply to
Erik Olsen
So machine them as parallel depth bevels, it was a dodge brought out in WWI so engineering shops could do bevels along a simpler line. It save the hand fitting needed to part of the addendum.
John S.
Reply to
John S
Doesn't that involve a second cut with the gear advanced a bit to thin the teeth?
I'm sure Ivan Law had something to say on the subject.
regards Mark Rand RTFM
Reply to
Mark Rand
There are errors in Law's methods. Been a recent post about cutting bevels on this forum.
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Another thought to keep the costs down as the gears don't need to transmit much load is to use an off the shelf gear with a smaller O/A dia and bore, then bore it out to suit the 7/16 shaft.
Jason
Reply to
jasonballamy
You need a dividing head which can be tilted, you will find the calculations in Machinerys handbook. I have done several but it does take time and concentration, If you need help contact me. Peter
Reply to
petercolman45
So machine them as parallel depth bevels, it was a dodge brought out in WWI so engineering shops could do bevels along a simpler line. It save the hand fitting needed to part of the addendum.
John S.
Is this the thing -
ME Vol 130, No.3261 p814 "Cutting bevel gears by the parallel depth method" by R.S.Minchin might offer some sensible advice.
Reply to
Steve
So machine them as parallel depth bevels, it was a dodge brought out in WWI so engineering shops could do bevels along a simpler line. It save the hand fitting needed to part of the addendum.
John S.
Just found this as a legitimate PDF download - Handbook for machine designers, shop men and draftsmen (1916) which has trhe design data and method on p113 - 116
Reply to
Steve

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