For Mark Rand - More gear-related stuff

Thanks for that.

I'll just nip out and turn a bit of extra length onto the 2 1/4" arbours I was using to turn the gear blanks. Now where did I leave that putting-on tool? :-)

More specifically, I've been working on the assumption of a 1/2" arbour at the drive end and whatever fits for the other end, with centres at both ends, because they have been turned between centres anyway.

I've not been bothering with threading them, since I've been holding the gear blanks on the arbours with Loctite 603.

These are the sort of thing I've got now:-

The top picture shows a couple of arbours, one that has been used to turn the blank down to size on. They are too short.

The Middle picture shows one of the slightly awkward gears, The shaft is 1/2" diameter, so that's good, but the total length is just shy of 4 1/2" and will want a bit extra for clearance from the tailstock. I'll extend it beyond the gear to a total length of 6"

The bottom photo is the awkward one. The shaft to the left of the pinion is

1/2" and 45 thou smaller than the tooth root diameter, that's ok. The shaft to the right of the pinion is 17 thou _larger_ than the tooth root diameter and is also a needle roller bearing surface. I think that I need to make something like the picture below the photo, again for a total length of 6"

Regards

Mark Rand RTFM

If I were doing this for a living, I wouldn't even make enough to starve on, but If I were doing it for a living I might not enjoy it so much.

Let me give it a bit of thought tomorrow and check measurements on the machine, you might not need to make too much use of that expensive putting-on tool. I'll get back to you.

Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Don't worry about that, I'm having fun and have just about got the hang of making the things to the desired tolerance.

PS

If anyone wants to see why the gears need replacing, clicking on the lower two photos and suffering the full size pictures shows the reason.

No progress tonight because I had to go back into work, and tomorrow night is the office Christmas party (I'm organising it, £450 bill and an indeterminate wait for expenses) If I'm sober on Thursday, I've got a day off to play in :-)

Mark Rand RTFM

Do the needles actually run on the shaft? or does the bearing have a proper inner race? If the latter, a few 'tooth marks' where the hob runs off won't matter greatly. How long is the leadscrew? I'll have to check, but I think the 1/2" shaft could be 'lost' down the drawtube. Alternatively, is the bearing surface bigger dia than the leadscrew, & what dia is the leadscrew? Might there be mileage in shrinking a sleeve on for the bearing, if the dia is bigger than the screw?

Cheers Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

The larger dia. one should be OK if it can be reversed, ie the longer shaft at the collet end. Is it 1/2" that end? Similarly for the smaller gear, if the longer end can be held in a collet it should be OK.

*If* the shaft can pass into the drawtube, and it's centred at the gear end, that should be doable.

I'll make a point of checking later this morning. Off to the dentist now :-(

How's the hangover ?

Cheers Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

I've now checked, a W20 collet will pass 9/16" through, and the drawtube looks to be made to match. It's stuck in a corner at the moment, so I haven't physically tried but can't see any reason why it shouldn't. For what I assume is your cross feed screw, it probably wouldn't be essential to have tailstock support as it's a small gear which could be mounted pretty close to the collet chuck. Otherwise it's probably not a massive job to take the centre out of the tailstock and make a little bush to stop the screw floating about.

Cheers Tim

Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service

Actually, the smaller one isn't a gear, it's an arbour that hasn't got a gear on it yet...

All the arbours are ending up with centres on them at both ends because they are being turned between centres!

It took a while to get going this mor^H^H^Hafternoon :-)

Mark Rand RTFM

Because the cross feed screw pinion and bearing journal are going to be a bugger to harden without turning the whole thing into a corkscrew, I've re-thought the way I'm doing that one. I'm going to use a bearing with an inner ring and use a 1" long inner ring as a coupler between the pinion shaft and the screw shaft. So the pinion will have a 3/8" stub shaft at the end rather than the 9/16" it's got at the moment. The original pinion must have been cut on a gear shaper in order to avoid messing up the 9/16" journal that's next to it.

That means that I'll have to bore the hole in the saddle out from 3/4" to

13/16", but that's manageable.

Mark Rand RTFM