Involute gear cutters?

[Bo’sunParticipant @bosun58570]

Good afternoon,

I need to buy a DP involute gear cutter/cutters to make two gear wheels. Am I correct in assuming I need to select it depending on how many teeth each gear has?

[Bo’sunParticipant @bosun58570]

Buying the right one(s)?

[not done it yetParticipant @notdoneityet]

Yes, and the correct DP and pressure angle. Likely more than one if tooth counts differ by just a few.

[geoff walker 1Participant @geoffwalker1]

I think they're numbered 1 to 8

Number 1 cutters for a large number of teeth down to number 8 which cuts gears with 13  teeth.

Some years ago I bought 3 cutters numbers 6,7 and 8 to cut 3 gears 20t, 16t and 13t. all cutters around 25 quid each from rdg in halifax.

The cutters were great, still using them now

Geoff

Edited By geoff walker 1 on 23/06/2021 13:24:33

Edited By geoff walker 1 on 23/06/2021 13:25:20

[Howard LewisParticipant @howardlewis46836]

If do not already have a copy, it might be worth getting Ivan Law's book "Gears and Gear Cutting" No 17 in the Workshop Practice Series.

The formulae in it are invaluable.

As warned, you need to ensure that the cutter is for the correct DP AND Pressure Angle.

Cutters are numbered 1 to 8

No 1 – 135T to Rack, No.2 – 55T -134T, No.3 – 35T – 54T, No.4 – 26T – 34T, No.5 – 21T – 25T, No.6 – 17T – 20t, No.7- 14T – 16T, No.8 – 12T and 13T.

It may be that cutters for Module gears are numbered in reverse order. Anyone to confirm?

Module is the Metric equivalent to DP

HTH

Howard

[Anonymous]

Posted by Howard Lewis on 23/06/2021 14:26:59:

It may be that cutters for Module gears are numbered in reverse order. Anyone to confirm?

Correct, annoyingly module cutters are numbered in reverse.

Andrew

[egaParticipant @ega]

I seem to recall someone who bought a set of module cutters which *were* numbered as for DP.

Plus one for Ivan Law.

[not done it yetParticipant @notdoneityet]

The range for the cutters is that the cutter is sized for either maximum or minimum of its range (can’t remember which). That means that the odd tooth (or maybe two) difference will make no odds if the tooth counts are top of one range and bottom of the next one up – ie no point in getting two adjacent numbered cutters if one gear is only a tooth outside of range. Thought and common sense needed to be applied in these marginal instances.

[Anonymous]

Posted by not done it yet on 23/06/2021 18:28:40:

….the cutter is sized for either maximum or minimum of its range (can’t remember which).

An involute cutter has the correct tooth form for the lowest number in its range.

Andrew

[Chris CrewParticipant @chriscrew66644]

I have bought several involute cutters from RDG and found them to be very satisfactory. I would not hesitate in ordering some more when required. I have cut gears and racks using the 'Myford' method, with the dividing head mounted on the vertical slide and now mostly on an horizontal mill with a Vertex BS 0 dividing head. Both methods worked for me and the gears and racks mesh and perform their intended function. How precise they are I have no idea but as an amateur pottering around in a back-shed workshop I don't have to submit to any inspection process. I can also highly recommend Ivan Law's book.

 

Edited By Chris Crew on 24/06/2021 08:26:11

[Bo’sunParticipant @bosun58570]

Thanks all for the confirmation.

[Author]

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