Cutting Meccano Spec gears

From memory, the standard gear pair that meshed on 1" centres are

38/38 50/25 57/19 60/15 The best fit for those gears is 38 dimetral pitch (DP) OD of the blank = (no of teeth +2)/38 inches No idea of the pressure angle. Could be normal 14 or 20 but knowing meccano could be a special. You might find locating 38dp cutters difficult and have to make your own.

Ivan Law's book on gear cutting could help you with this.

Good luck

Bob

There's a website out there that goes into great detail on this. I seem to remember that it arguess that Meccano used a commonly available cutter.

Try

Russell

The gears are 12tpi. Allegedly can be cut with a 3/4"BSF tap as a hob.

Mark Rand RTFM

Looking at the replies, the sense of it is that it's all a bit of a compromise. The project uses four meccano gears the small brass spurs that will look the part, and two larger steel gear wheels (127 and 56 tooth from memory) and look cheap and nasty, which are the ones I intended to replace with home made versions in either brass or cast iron, machined to look the part. Sounds like I'd be better off making all four from scratch to a current standard.

Looks like a 0.7module or 40dp cutter would be the place to be and make all four gears instead of trying to make to the Meccano standard.

Thanks

Steve

I'd forgotten I had the Ivan Law book :-)

If I look at pages 114 and 115, there are instructions to guide making custom gear cutters, but the dimensions in the two tables (for 20deg PA and

30 deg PA) don't seem to work.

The form tool uses two steel buttons of 51.30 inches, (normalised at 1DP) but the distance between centres is given at 49.6 inches, surely the minimum distance between the centres is 2 x the radius of the two buttons? ie 51.30inches.

Steve

Meccano Magazine published a gear cutting machine (made of Meccano) that used a 1/2" BSW tap as the gear cutting hob. I don't remeber which issue and it would take me some time to find it as I don't have an index. The gear cutting machine worked OK for plastic - not sure about anything harder. Keith

Thanks Keith - hot tip! Here it is:

I have a Mikron Hobbing machine and if you sent me some suitable blanks I could fairly quickly put some teeth around them for you, the 127 tooth would not be an option as I dont currently have that changewheel setup, but most other numbers are OK if you can make some adjustments to the design to suit. 38 or 40DP hobs are both in stock.

Phil

The actual gears are:

2 off 19 teeth 1 off 57 teeth 1 off 95 teeth

My eMail address is good - if you let me know the diameter of the blanks you would need and what the beer token tally is that would be great. The material for all four gears will be brass.

If all four are cut from scratch, then just use the best hob that suits the tooth count.

Steve