Gear cutters

[RICHARD GREEN 2Participant @richardgreen2]

[RICHARD GREEN 2Participant @richardgreen2]

I am building a 6 " Burrell traction engine and I would like to cut the gears myself,

It all seems straightforward enough, however I have one question,

The two sliding gears on the crankshaft are 25 and 34 teeth 6DP,

A no.4 cutter will cut 26 – 34 teeth,

and a no.5 cutter wil cut 21 – 25 teeth,

Could I get away with the no.4 cutter to cut both gears, ?

Or is it important to only cut the amount of teeth recommended for each cutter ?

Richard.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi, you can not use the same gear cutter for the two gear wheel with teeth who is far away from each other due envolvent in the gear teeth. In teoretical is possible if near the counts of the teeth, but the envolvent is difference from the smallest gear wheel to gear rack.

Best to use the gear cutter no. 4 and no. 5 and get correct fit between the gear wheel after running-in period is done.

Edited By Jens Eirik Skogstad on 24/05/2012 22:04:37

[John Stevenson 1Participant @johnstevenson1]

In thoery no, in practice yes.

The number 4 cutter is only truly accurate for the lowest count gear which is 26, the greatest error is on the 34 tooth gear.

The differences between a 25T overlayed onto a 26 tooth are 0.002" maximum at the greatest error.

If the worst comes to the worst then cut the 25 tooth gear 2 thou deeper. I can supply a geometrically correct CAD drawing but the picture software on this site sucks more than a hoover and the quality also sucks.

John S.

[JasonBModerator @jasonb]

If you do it with the single cutter use a gear depthing tool to make sure your shaft centres are correct rather than setting them out for the correctly cut gear PCD's.

J

[chris jones 14Participant @chrisjones14]

Richard,

Did you ever sort the gears? I am after getting some gears and looking at options. Not sure I could machine something this dia, or have the skill to get it right without making 5 sets?

I have bought a part complete engine and am keen to talk to someone who has been through the process, would you fancy a chat?

019467 25755

Cheers

Chris

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