Cutting gears?

[Gareth's was W7 now W10 Downst]

What's the favoured approach to getting hold of gears, to cut them yourself, or to buy from, say, HPC gears?

[The Natural Philosopher]

i buy from wherever

depends on what size

[harry]

You are not likely to have the equipment needed to do this .

[Gareth's was W7 now W10 Downst]

Actually the reason for my query is that last year I bought a Jacobs gear hobber for a reason that has now gone and I was wondering if there might be a market for its sale.

I have a 55 year old dream from the days of my impoverished teenage years that I would make my own communications receiver to compete with the likes of the best at that time, and I intended to cut gears for the tuning dial but recently have obtained the rolls royce of dials, the Eddystone 898 so no longer need the hobber.

[tabbypurr]

Of course there's a market. Silly question. As is the choice of buy or cut, anyone that can buy the gears they need/want will do so.

[Another Dave]

I used my 3d printer to produce the gears and pulleys for motorising my astronomical telescope.

Your application may be somewhat more strenuous.

Another Dave

[Gareth's was W7 now W10 Downst]

What module or DP for those gears, because AIUI there is a limit to how small something can be extruded from a 3D printer?

[John Rumm]

Hobbed gears are nice, but not the only way to cut teeth. Milling with a single gear cutter is less equipment intensive.

[Brian Gaff]

The parameters for teeth are many and its a bit of a minefield. Most gears these days seem to be made of a crappy form of Nylon and lose teeth. If they are to be custom made, say for fixing a curtain closer etc, then it might be good to get them made from something more robust. Or are you refurbishing an Aerial Rotator? Brian

[Brian Gaff]

Ah OK. So are you saying you want to fix it to flog it? I remember seeing the drawings for some gears used in Radar turning units, and it was a scary lot of measurements of pitch, and form, ie shape, and remember the right diameter and pitch are needed before you start or you end up with half a tooth at the end.

Brian

[Another Dave]

I'm just using the standard 0.4mm nozzle because it's OK for my application. 0.2mm is the smallest practical size.

I'm using pulleys with GT2 toothed belts mainly, but a worm and gear arrangement for the focusser.

The patterns for the printer are generated by Autoscad

using (for gears)

and (for pulleys)

Both are quite difficult to use (the gears thing is in German!) but very rewarding.

Another Dave