Duomo VM-20 (Bridgeport clone) power feed

The gear has stripped on the bottom of my power feed, are they available?

it's a Chuan Siang

Type 1000A

Date 1985

No. 5026

Fingers crossed!

Have you looked in the bottom of the cover as they often pack a spare gear there ?

Edited By John Stevenson on 11/02/2015 14:46:22

HI Allan, a few calcs suggest that it might be a 30 DP gear, the problem you may have is finding a replacement with the right helix angle.

Is it the bore or the teeth that have stripped?

Neil

I suggest you contact HPC gears of Chesterfield their phone number was 01246 268080, but you will need to know the gear technical details.Ted

Thanks for the rapid replies!

@Neil - it's the gears that have stripped

@Ted - I sent them over some details and gave a rough quote of £100 for a blank & £140 - £160 with milling.

I do have a dividing head that I bought from Axminster a few years ago but would have to study on how to use it and to work out what the pitch DP etc etc.

Allan

Gimme a bit as dinner in in the dog and I'll pop the cover off an align unit and see what that looks like as the Align gears are available easily

Manuals for Align power feeds are here. Include exploded view, parts list etc.

If it's the ubiquitous AL500, part number 102 looks suspiciously like this gear.

Where do you get spares in the UK? The Auction Site?

I've spent some time looking at the Align gears and they seem to be 107 teeth and the hole is larger.

Yes got one of my spare gears here 107 teeth 91.3mm OD and a tapered hole in the centre 42mm on the smallest diameter.

If you lay a protractor across the teeth and let me know the angle I can attempt to 3D print you one early next week.

I do have some decent gear software to work all this out.

Are you sure your gear isn't 107 teeth? That woudl make it almost dead to szie for 30 DP rather than pretty close...

You can always bush one of the align gears.

Neil

Neil,

How are you working out the DP ?

Because without knowing the helix angle none of the quick add two teeth formulae work.

As an example 108 teeth 30DP 10 degrees helix  gives an OD of 94.5mm

Increase to 15 degrees and the diameter increases to 96.35 and at 20 degrees helix it's now 99.0018mm OD

Edited By John Stevenson on 12/02/2015 14:50:26

Hi John & Neil

108 teeth for sure!

Wow, didn't expect the offer to make one, would love to see that on You Tube! I'm willing to pay obviously.

I don't have anything to measure the degree angle at work but have put marker pen on it and rolled it out, I will measure it later.

Thanks for all your help and comments

Allan

Working in AutoCAD from the jpg I get 15 degrees

Quillstar in Nottingham have been selling new Zytel gears for the Align power feeds for a few years, they are currently £35, but I think they are 107 teeth.

> Because without knowing the helix angle none of the quick add two teeth formulae work.

;-P

OK peeps, working off what we have as regards number of teeth, OD and we take the pitch angle as 15 degrees which sounds reasonable as they often work in 2 1/2 degree increments for some obscure reason.

The DP works out as 31.42 but more telling is the Module at 0.81 which we will ass-ume is 0.8

Now i don't mind having a go at printing one of these but my printer, UP!2, can do various densities as regards fill but it cannot do a complete fill. Probably as it uses to much filimant and / or takes too long so

[a] Not sure how strong it will be, and

[b] not sure what the tooth detail is like on something as fine as 0.8 mod but prepared to give it a go.

Alternative is to hob one but not sure if I have a 0.8 Mod hob and if I have I will have to make mandrels etc for it as I'm fixed on 1" or 1 1/4" bore hobs, not 10mm ones.

Alternative is to mill one using Gearotic which allows you to cut involute gears with an end mill, no special tools.

Drawback to this is the size of cutter needed, according to the screen shot it has to be smaller than 0.6 mm

That's an impressive demonstration, already, John.

This might be a useful time to mention that SurplusShed stocks loads of plastic gears, some of which are weird and/or wonderful. They happily ship to the UK, at realistic prices, and their service is excellent.

Incidentally: Those with an interest in Optics will be impressed by their product range !!

MichaelG.

Edited By Michael Gilligan on 13/02/2015 08:25:02