Frame help

[garygfletcher]

I'm trying to put this frame together.

 

The gears just won't spin free.

 

Have I been given the wrong set? They seem to mesh if I pull them apart a bit.

 

It feels like the etch is perhaps out? It certainly is on the body. Could be wrong..

[garygfletcher]

Movie to demonstrate

[CF MRC]

Whose etch? I'm at Keen House today

 

Tim

[Orange Cat]

Those gears don't look like they match. The larger one has bigger teeth and a coarser pitch. It is hard to judge from the photo but it looks like one of the old 64DP ones while the smaller one is finer, possibly a Metric M0.3 one. One of them, at least, is wrong.

Does the small gear mesh wth the worm? If so, then I think there should probably be another gear to go on that shaft to mesh with the larger one.

[CF MRC]

They do look like mis-matched gears.

 

Tim

[Caley Jim]

Those gears don't look like they match. The larger one has bigger teeth and a coarser pitch. It is hard to judge from the photo but it looks like one of the old 64DP ones while the smaller one is finer, possibly a Metric M0.3 one. One of them, at least, is wrong.

 

I agree with the moggie and Tim.  That was my first impression too.  When you pull them out, the spacing will effectively open up, which is why you can turn them then.

 

Jim

[garygfletcher]

Thank you all, at 3am every thing looks the same! I bought the gears with the etch owner at tutbry. They were tge wrong ones unfortunately. Luckily I had some in my own stock, still mush tighter than I would like though.

 

 

With regard to the acetal axel muffs how does one secure the gear? Is it just push fit? And what about the centre gear to the worm? I was thinking I might have to put the rod in and turn down on the lathe - perhaps the stepped muffs were the wrong type also?

 

Thank you

[Caley Jim]

With regard to the acetal axel muffs how does one secure the gear? Is it just push fit? And what about the centre gear to the worm? I was thinking I might have to put the rod in and turn down on the lathe - perhaps the stepped muffs were the wrong type also?

I've always just push fitted the gears on the muffs.  When you say 'the centre gear to the worm' I presume you mean the gear beside the worm-wheel.  Again a push fit should be adequate.  It's a wee while since I built a loco and I've always used the 100DP gears with a 14T beside the worm-wheel on a stepped muff.  I've no experience of the new metric gears.

 

Jim

[CF MRC]

The stepped muff should bring the worm wheel on-centre. With gears on, the stub axles will generally expand the muff a bit in the gear so it should all get very tight.

 

Tim

[Izzy]

You need to break the inside edges of the bores of the gears to ensure they push nicely onto the muffs whatever sizes are involved. You shouldn't need/don't want to reduce the muff o/d, they will be loose otherwise. I believe current wheel stub axles are machined to be a good push fit into the muff bore, but again it helps to break the axle edges so they enter the bores smoothly. Twisting gears and wheels while pushing is a way of easing them in/on. The acetal will 'give' a bit and then tends to lock itself onto gear/axle after a while.

 

Don't know if these will help.

 

 

 

A 1/8" bore 30-1 gear wheel on a stepped muff with a 3mm bore M0.4 14T. There is a flange between the gears as a spacer and a slight space before the end of the muff, you can probably see it stands proud - so the small gears face doesn't rub against the frame/axle bush.This is what you need if you have a mix of imperial DP 1/8" bore and MO metric 3mm bore gears. All new supplies are now 3mm including the worm gear sets.  The all 1/8" gear muffs also have a flange spacer but the 3mm gear muffs don't so gear spacing is down to you. I just tap them gently through using a small hammer while between vice jaws where it's needed.

 

Izzy

[Caley Jim]

You need to break the inside edges of the bores of the gears to ensure they push nicely onto the muffs whatever sizes are involved. ........

It's also worth having a good close look at the edges of the teeth on the gears.  If there is any roughness there it can cause meshing issues and make the gears seem tight.  A light rub through between the teeth with a fine knife-shape file is usually enough.

 

Jim 

[Nigelcliffe]

It's also worth having a good close look at the edges of the teeth on the gears.  If there is any roughness there it can cause meshing issues and make the gears seem tight.  A light rub through between the teeth with a fine knife-shape file is usually enough.

 

Jim 

 

Agreed. but for most people, a "fine file" isn't the one in a cheap needle file set.    Cheaper option than expensive files is a bit of fine wet&dry paper to remove the roughness at the edge of the gear teeth. 

 

( a few weeks/months ago, I added advice to that effect to the 2mm products pages after seeing some current gears with quite a bit of machining flash on the corners of teeth.   Its quick and simple to deal with if you are aware of it ). 

 

 

- Nigel