48DP gear cutters needed 14-1/2PA, no 4 and no 8

[TiddlerTadParticipant @tiddlertad]

Hi
I'm in the process of building a Jerry Howell v-twin IC engine. I've managed to purchase number 5 and 7 cutters from RDG Tools, but I can't find a UK supplier with number 4 or 8. I've tried Tracey Tools, Home and Workshop Machinery, eBay etc. Some US suppliers have them but they are far too expensive after paying carriage and import duties.
I had considered converting to Mod 0.5 but I really want to stick to the drawing spec if at all possible. A gear hob isn't feasible either, as I don't have the necessary equipment (at the moment )
So, if there is anyone in the UK who would be willing to sell me either number 4 or 8 cutter, please contact me. My email address is learningturningmetal@gmail.com
For info, I live near York and I am covering the build on my YouTube channel (learning turning metal).
Cheers
Andrew

Edited By TiddlerTad on 18/06/2022 09:38:47

[TiddlerTadParticipant @tiddlertad]

[HopperParticipant @hopper]

HPC sell a full range of DP48 gears readymade if you wanted to go that route. Not as much fun but maybe easier?

[Brian WoodParticipant @brianwood45127]

Hopper,

HPC gears will all be to 20 degrees PA and whilst they will mesh with the others, life of the gears thus meshed in service will be short

Regards

Brian

[HopperParticipant @hopper]

Yes you have to make them all 20DP. Still might be cheaper than importing cutters.

[bernard towersParticipant @bernardtowers37738]

Any reason for not using 20 deg gears?. They are stronger and tooling is more commonly available.

[John HaineParticipant @johnhaine32865]

Make your own cutters by the button method?

[HuubParticipant @huub]

Making gear cutters isn't difficult and you can make them using a mill, a vice and a tapered drill (centre drill)

Making gear cutters and cutting gears

[HopperParticipant @hopper]

Posted by Huub on 18/06/2022 22:47:23:

Making gear cutters isn't difficult and you can make them using a mill, a vice and a tapered drill (centre drill)

Making gear cutters and cutting gears

Great video. Thanks for that.

[DiogenesIIParticipant @diogenesii]

For a light-duty application, depending how close the desired tooth count is to that of the cutters that you have, using those will make a pair of gears that mesh and run together acceptably.

For example if you need say, a pair of timing gears for a model engine, using a '5' cutter to make a 30-tooth instead of a '4', and '8' to make a 15-tooth pinion instead of a '7' is probably a realistic option..

..dependent on the sizes / desired clearance you may need to slightly adjust the centre distance..

I wouldn't use this method for a timepiece or power transmission, but for certain applications it will work and the results can be surprisingly good – involute cutters are a very loose approximation in any case.

If you want to try out the cutters that you do have, it's probably worth making a 'trial' pair in some easily cut material like brass, alu, or even acrylic, and seeing how they mesh..

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