Member postings for Russell Eberhardt

This is what I use: **LINK**

Russell.

More sad really that they are destroying their goodwill and thus eventually, unless they do something about it, some good magazines.

However, a quote from Katherine Scott in an earlier post:

"B/ Yes the Online Archive is available with the Digital only subscription."

I take this to mean that the current web based online archive will continue. Are you reading this Katherine (or anyone else at MTM)? Would you like to comment?

Russell.

You've made a good start Allan. Well done.

Russell.

There is one big advantage Colin. A three phase motor has more or less constant torque throughout it's rotation while the torque output from a single phase motor varies with it's angular position resulting in vibration.

Since fitting an inverter drive to my 1950 ish lathe I get a much improved finish. However I still do most of the speed changing with the belts.

Russell.

Keep us up to date with your progress.

Russell.

Yes, I do the same. Drawing with Draftsight (free program) and printing on an HP laserjet. I think it is more accurate than I can achieve with a scriber. Best not to use cutting fluid though!

Russell.

Amen to that!

Russell.

Can you then archive it to DVD so that you are sure of keeping it or is there some clever security system?

Russell.

That's fine if your nearest club isn't 1000 km away! I've already thrown out most of my backnumbers to save space and now I'll no longer be able to access them on line unless I am prepared to increase my subscription considerably.

Perhaps some kind soul will put the backnumbers on one of the pirate websites and Mytimemedia will realise they are shooting themselves in the foot.

I wonder what they'll do next to piss off their customers.

Russell.

John S,

I think you posted your pictures the wrong way round

Russell.

Hi Steve,

I have now read that lantern pinions give less friction than solid ones when being driven by the wheels and more friction the other way round. Don't know if this is true or not - must do some more research.

Do you know the correct relationship between wire size and module? I cant seem to find that in any of my books.

Russell.

Thanks, I may need the luck!

I made the same mistake as you with my first clock and had to take it apart and open up all the pivot holes to make it more rattly. It now runs well keeping time to about a minute a week. I'm hoping for nearer a second a week with this one.

Russell.

Thanks Roy,

I'll probably go for solid pinions then. I'll buy them in as it's cheaper than buying the cutters.

I didn't think that the weight of the escape wheel assembly was important. It's the moment of inertia that is important due to the stop/start motion. The moment of inertia is the sum of M x (R x R) so weight near the centre of rotation is much less important than that near the edge. However every bit helps so I'll use the smallest ball bearing I can find, 1mm ID x 3mm OD should do it.

Russell.

Thanks for your replies. I found an interesting paper on the use of ball bearings here:

**LINK**

In that paper he has measured the friction in a ball bearing pivot to be about 70 times less than a conventional pivot. He has also calculated that the life of the bearings he has fitted to his clock works out at between 11,000 and 31,000 years although he does point out that the calculations may not be wholly valid at this extreme. Replacement is unlikely to be needed for a considerable time and I suspect by then they will be using totally different bearings which could be fitted and have even less friction.

I too have seen comments that ball races don't like intermittent motion, I can't find any references to any tests having been performed. However I doubt it will be a problem with our very light loading.

One more question: Does anyone know which give the best performance, cut pinions or lantern pinions? I guess it's easier to get a good finish on the working surfaces of the latter.

Russell.

Hi

I have just received the book and intend to have a go at making the month going version. Has anyone else here made one - any hints or tips.

I am intending to make a few modifications:

First I'll fit ball bearings to all the pivots. Modern miniature ball bearings have very low friction, even lower than jeweled bearings. I intend to fit them in eccentric bushes to enable the meshing of the pinions/wheels to be adjusted by a few thou. Something like this:

That should eliminate a problem I had with my skeleton clock where I had to bush and re-drill one of the pivot holes where the meshing was too tight.

The second proposed modification is to replace the one piece pallet assembly with the adjustable type of pallet frame with separate pallet nibs.

I'd appreciate any comments on these modifications.

Russell.

It's what is called a Driving Truck. There are two types, one for raised track and one for ground level track.

Russell.

If you cant find the size or grit size you want you can always make your own:

**LINK**

Russell.

Alan,

I believe you said that the white wires come from the start switch. So the motor itself only has four wires coming out so it is not as per original and has been rewound. The N terminal is probably the star point.

Have you done as I suggested and checked for continuity of each winding? I see you have a multimeter.

Your symptons suggest to me that one of the windings has gone open circuit if so you will need a new motor. It is cheaper to buy than rewind. I've had good service from **LINK**

Russell

If the white wires are coming from the start switch you only have one wire from the windings on terminals A, B, and C so it must be star wired. I can't see what's on terminal N, are there three wires there? If so and your converter is 230 V you need to rewire it for delta. If your converter is 440 V it should be OK. Perhaps one of the windings is open circuit or disconnected, check for continuity from each of terminals A, B, and C to terminal N.

Russell.

First you need to determine if it's a problem with the motor or the converter. Have you been able to try the converter with another motor?

Does the motor turn freely by hand with the belt disconnected when not powered? Try spinning it by hand when powered (carefull of fingers!), it could be a starting problem with the converter.

As has been noted, this motor should be wired in delta for 230 V operation, have you checked that? The motor is unlikely to be faulty but you could check the continuity of each winding (disconnect one if it wired in delta) with your meter.

Please post the results of any tests you do.

If the converter is faulty I would buy a 0.75 kW inverter. You should be able to find one for less than £100 new.

Russell.