Identification of gear cutters

[Kerry GascoigneParticipant @kerrygascoigne56747]

Hello members.
I am looking to the expertise of the group to help identify some gear cutters that I am hoping to use.They are at least 50yrs old and were used by a chap who made clocks for a hobby. The cutters are all labeled in the same fashion.

Cutter No 1 has a theta symbol followed by 42,5 and then 40Z
Cutter No 2 theta 10,3 8Z
Cutter No 3 theta 22,6 30Z
Cutter No 5 theta 33,8 52Z
Cutter with no number (but possibly4) theta 42,8 40Z
There are several other cutter similaly labeld but looking different.
If I could get a handle on the marking system I could be in business to make the gears for the Jerry Howell hit and miss engine that I am halfway thro making.
Cheers,
Kerry

[Kerry GascoigneParticipant @kerrygascoigne56747]

Gear cutters

[JasonBModerator @jasonb]

If they are clock making cutters then the cyclodial form is unlikely to suit your hit & miss engine which will want involute cutters.

J

[Phil PParticipant @philp]

If I had to hazard a guess, I would say the first number is the outside diameter in millimetres and the second is the number of teeth.

In which case you have cutters for very approximately the following sizes

1 mod (24DP), 0.7 mod (36DP) & 0.62 mod (40DP)

I agree Cycloidal gears will not be any good for an engine.

Phil

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