Gear suppliers

[Big Jim]

Does anyone know of a good source of brass gears?
I need a selection with a 1/8'' bore, I can find plenty of suppliers that list metric sizes but no one seems to list imperial ones. I know that 1/8'' is a gnats under 3.2mm and I suppose the .2mm won't make that much difference but I would prefer something correct.

[tuppenced]

Does anyone know of a good source of brass gears?
I need a selection with a 1/8'' bore, I can find plenty of suppliers that list metric sizes but no one seems to list imperial ones. I know that 1/8'' is a gnats under 3.2mm and I suppose the .2mm won't make that much difference but I would prefer something correct.

The mere 0.2 mm will mean you can't fit the gear on your axle!

Easy alternatives are:

- Get a 1/8" Hand Reamer.

- Use 3mm diameter axles.

- Go for 1/8" bore Delrin gears, which are generally superior to brass anyway.

You can get Delrin gears readily either from manufacturers Serv-O-Link in the USA (minimum order $30 last time I looked) or from one of several UK importers.

Let me know if you are stuck, because I have a small stock of garden railway sizes.
I ask for £1 per $ list price (remember, I've paid airmail postage, Duty and VAT on that $) plus UK postage.

David 1/2d

[Busted Bricks]

David, since you mentioned you have access to a laser, try cutting some gears on it. I have cut MOD 0.5 gears from 3mm acetal/delrin on mine. Because you get the slight taper from laser cutting you just flip one gear and they mesh perfectly. White acetal can be dyed with RIT or Dylon. You will have to drill or ream the center hole - a laser does not produce great quality holes. Fine for marking the center though. If you use a 2.9mm drill you get a very tight fit on a 3mm axle. I use Gearotic Motion to generate gears but there are many other programs that will do it, even some free ones.

The gears without spokes in this pic are MOD 0.5 and they are all dyed with Dylon

Michael

[Busted Bricks]

PS: I agree that delrin gears are better than brass in many applications as long as they are not subjected to high temps. However people see them and think "cheap plastic" so go for brass. Of course there is also the look but as I have shown there are ways to improve that. For some reason thin black delrin sheets are hard to obtain in UK.

Of course I have 40 meters of 30mm black delrin rod and some gear cutters.... Just need to start on the digital indexer.

[Big Jim]

Thanks for the advice gentlemen.

I think the 1/8'' reamer is the way to go. What is causing the problems is that I have acquired a number of SM32 wheels with 1/8'' axles.

[Busted Bricks]

Once you leave EU you can go back to your old imperial ways

[Big Jim]

Can't wait.
I am also looking forwards to being able to send small boys up the chimneys to sweep them.

[tuppenced]

I love the laser cutting tip, Busted Bricks, even though it wasn't me wanting gears and I'm not allowed to cut acetals on the school laser.

For anyone with the opposite problem (needing gears for metric axles) good old Serv-O-Link also make some metric-bore Delrin gears and sprockets, though I suspect you might have to buy them via the UK.
    I stock those too, for the convenience of myself and friends.

[Not a lot of people know that, just as not a lot of people know that the US first authorised everyday units to be based on the metre and kilogram in the Metric Act of 1866 - 150 years ago! - and made such units compulsory in the Mendenhall Order of 1893.
     If ever the UK were to revert to Imperial, it would be to the SI version, rather than the pre-1958 units.

And if ever the UK does leave the EU, it will be in the same position as Norway and Denmark, i.e. legally obliged to obey EU regulations - and to pay towards them - but without its voice at the table any more.]

David 1/2d

[sstjc]

Just to support David 1/2d and Busted Bricks comments Delrin is now used almost universally by manufacturers of electrically driven 5" gauge engines. I have owned several such engines which suffer proportionately higher stresses and stand up very well to the abuse they receive in such environments. I would have no concerns about recommending these gears or using them myself. Its a brilliant material for gears.
Barry

[tuppenced]

I suppose it's time to answer Big Jim's original question - where can he get a selection of 1/8" bore brass gears?

Try HPC Gears http://www.hpcgears.com/

Or Reliance Precision https://www.reliance.co.uk

They both do 1/8" bore worms, spurs, helicals etc with brass (or at least bronze) as an option.

Not as cheap as hobby gears, and possibly more limited in sizes because industrial gears have the bore proportionate to the diameter. But a wide range of stock gears nevertheless.

As ever, an industrial catalogue takes a fair degree of decoding :-)

This site just does one size of pinion: http://tinyurl.com/jg9qsvc

while this American firm does several ranges in metal, albeit not actual brass and rather fine in the tooth http://www.sdp-si.com/products/miniature-gears-inch.htm

Remember brass is a poor choice for either bearings and gears, but it's tolerated for toys and models because it's cheap and easy to machine and the duty is light and infrequent.

[tuppenced]

Another good gear supplier - North West ShortLine - albeit heavily into worms.

Gear catalogues at http://www.nwsl.com/uploads/chap4a_web_09-15.pdf and http://www.nwsl.com/uploads/chap4b_web_09-15.pdf

which include 1/8" bore brass gears.

Note the advice page on Part A from which I quote (emphasis mine):

[quote]In an apparently properly operating mechanism, excessive gear wear may occur. Our experience in modeling
and more recently in gear manufacture has led us to conclude that the most common causes of excessive wear
are:
1. Poorly made (or damaged) worm.
2. Improperly selected materials (most commonly a brass worm driving a brass wormgear - ie. Same
materials - wear out rate will be very high, usually whether lubricated or not). Driving gear should be harder
material than driven gear.
3. Worm not centered or too short for running mate wormgear.
4. Inadequate lubrication or lubricant (use a gear oil).
5. Improperly matched worm and wormgear.[/quote]

David 1/2d

[Big Jim]

Thanks David for your information. I think that derlin looks like the way to go. I had always assumed that brass or brass/steel combo was best but it would appear that times have moved on.

I have somewhat of an inbuilt resistance to plastic gears due to many years of suffering problems with cheap nylon products on various model projects and more recently as a Father being asked to repair my Son's toys!

Cheers
Jim