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Member postings for Russell Eberhardt

Here is a list of all the postings Russell Eberhardt has made in our forums. Click on a thread name to jump to the thread.

Thread: Removing bang in self tappers
28/09/2020 11:53:24

I found them easy to remove from vintage cast iron car engine blocks by filing flats on the edges and gripping with a mole wrench to twist them out.

Russell

Thread: COMPRESSION RATIOS
31/08/2020 16:28:08
Posted by Tim Stevens on 31/08/2020 15:34:28:

Sorry, Howard, but fuel with Tetra-ethyl lead was available from the early thirties. The Shell petroleum handbook 1933 says it is used in aeroplanes and US gasoline, and the 1938 edition refers to it as a regular constituent of motor spirit. Such fuel was often called 'Ethyl' as distinct from Benzole (with benzene etc from coal) and Discol (with alcohol from the Distillers Company Ltd.

Yes Pratt's Ethyl fuel became available in early 1930 and the 2.3 litre Talbot 90 was racing reliably with an unheard of 10:1 compression ratio. That enabled them to compete with the Bentleys with their 6 litre engines!

Russell

Thread: varifocals
31/08/2020 15:59:36

The only problem I have with varifocals is when working close to something overhear such as when rewiring a ceiling rose. For those occasions I have a pair of prescription reading glasses.

Russell

Thread: ultrasonic cleaning fluid ?
18/08/2020 20:49:28

I use this recipe for cleaning clock parts in my ultrasonic bath. It brings brass parts up to a lovely shine.

**LINK**

For general cleaning I just use a little dishwasher rinse aid in water. It is just detergent but doesnt foam.

Russell

Thread: Remote Controlled Boat
16/08/2020 09:54:28

Will it detect and give way to small sailing boats?

Russell

Thread: Carbon fibre pendulum rod
12/08/2020 11:22:06
Posted by Alan Crawley on 11/08/2020 19:35:38:
I’m beginning to realise my IQ is too low for this conversation!!

Surely not. Sorry if I have assumed too much.

To simplify things; Q is just a measure of how much energy is lost on each cycle of the pendulum and how much energy must be given back to it on each tick of the clock to maintain it. The higher the Q the smaller the energy is needed to keep it going and the less disturbance that it causes to the regularity of the clock.

Hope that helps.

Russell

11/08/2020 15:52:47

I did measure the Q factor of my pendulum with all fittings. I can't find my notes just now but I think it came out at about 6000. Easy enough - set it going and count the number of cycles it takes to decay to 37% of it's starting amplitude. Multiply that number by 2 x Pi to get the Q. The most important factor is the air resistance so best to use lead or even uranium for the bob and an aerodynamic shape. I stuck with steel not having uranium to hand!

Russell

10/08/2020 19:30:55

The supplier of the pultruded CF tube I used for my regulator quoted -0.1 to -0.3 ppm/C. I used a threaded bottom fitting for the rod for use with a regulator nut at the bottom of the bob. I calculated that making the transition from CF to steel 30mm below the centre of the bob would compensate for 0.2 ppm/C for the rod with a small positive contribution from the suspension.

Seems to work fine.

Russell

Thread: Another new member
09/08/2020 11:47:41
Posted by Peter Cook 6 on 09/08/2020 11:13:26:

Thanks. No plans for clockmaking! I have rather too many clocks as it is. In any case clockmaking would involve gear cutting and (after so many years in IT) I am averse to highly repetitive activities. That is what computers are for.

So clock making probably lies on the far side of a timeline that includes CNC - and I have a LOT to learn before I even contemplate that.

Hello and welcome Peter

I was always interested in clocks having taken old alarm clocks apart as a teenager to see how they worked. Most of them went back together and continued working!

In my retirement my wife bought me a Vienna regulator (American) on Ebay and I restored that and was pleased to get it working. Later, on researching my family tree, I discovered that three generations of my ancestors were watch and clock makers so I took the plunge and started clock making as well as repairing clocks for friends. Making gears (more correctly called wheels and pinions) isn't that tedious.

Your new mill is very good for small items and could be converted for CNC. I have an SX2P which I have converted for CNC and find it very useful for crossing out wheels which is more difficult than cutting the teeth.

Have fun.

Russell

Thread: Cleaning emergency !
04/08/2020 19:52:13

Replacing the floor covering in a camper van is by no means easy. The flooring is usually laid before the installation of the furniture so everything must be removed including the kitchen sink!

A possible alternative is to use floor paint. This is a useful guide: **LINK**

Russell

02/08/2020 21:42:34

Try Googling "Plasticiser migration". I think you're stuffed.

When manufacturing electronic products we used to have to be carefull how they were packaged to prevent the plasticiser from the power cable ruining the plastic case of the unit.

Russell

Thread: Opions sought on using the USB Photo Stick for photo storage
30/07/2020 10:24:38

Have a look at MEGAsync. Will automatically sync any folders on your computer with cloud storage. You can also set it up on your mobie phone to automatically upload photos (only when the phone is on charge so as not to flatten the battery). All free of charge for up to 50 Gb IIRC.

Russell

Thread: Why is there no side relief on a wheel cutter
28/07/2020 10:30:07
Posted by Clive Steer on 28/07/2020 09:45:44:

To see the machine check out Petermann on the lathes.co.uk site.

Clive

Some other fantastic machines in the Petermann range. Lathes with tool setting thimbles calibrated to one micron diameter!

Russell

Thread: Slitting Saw Arbor
19/07/2020 11:57:01
Posted by JasonB on 19/07/2020 07:00:16:

MC B, the stepped ones work OK if reasonable quality though I think there have been some poor ones about in the past which has given them a bad name.

Yes, I bought one several years back and it was absolute rubbish. The stepped circles were far from concentric. I stick to single size ones now.

Russell

Thread: Carbon fibre pendulum rod
19/07/2020 11:41:51
Posted by Emgee on 18/07/2020 23:26:52:

I'm sure that if anyone on here needs any specific shape or size of carbon rod/tube it could be produced by some of the current membership, at reasonable cost of course.

Emgee

That is if anyone has the equipment to do pulltruding. A normal lamination will not be stable enough.

Russell

19/07/2020 11:40:27
Posted by Alan Crawley on 18/07/2020 17:41:45:

I have one other small query about the CF rod, will it be ok where it is subjected to the friction of the crutch? This consists of two 3mm silver steel pins in a brass disc that can be rotated to adjust clearance to the pendulum rod. I would like to thank everyone who has taken the trouble to help me with my project.

I had the same worry at first but my regulator has the same type of crutch and, after five years of running, I can't see any mark on the CF tube.

Russell

18/07/2020 17:20:37

I used a pultruded carbon fibre tube for the pendulum of my regulator. I used 7 mm O.D. and 1 mm wall thickness. It has supported a 5 kg bob for the last five years without problems. I used slow cure Araldite to glue steel fittings to the ends. The fibre tube manufacturer quoted -0.1 to -0.3 ppm/°C and I have no reason to doubt that. You have to remember that the bob, suspension, and rod end fittings will all have a positive expansion coefficient but the threaded end of the rod for the regulating nut, combined with the bob itself can be made to approximately balance the expansion of the suspension.

The only unexpected effect I noticed was that the clock gradually slowed down over the first six months or so as the rod crept under load but it then settled down. I guess that was a result of the stress being redistributed from the epoxy to the carbon.

Hope that helps.

Russell

Thread: Vfd sizing
14/07/2020 16:57:13

I would go with the 0.5 kW one. De-rating electronics generally leads to improved reliability.

Russell

Thread: Con rods, stressman needed
14/07/2020 16:45:26
Posted by Dave Smith 14 on 14/07/2020 14:33:19:

The other thing is they lighter, you remove mass from the point where you do not not want it. Buckling comes down to stiffness again for a given load which is controlled by the cross section as you say. In my racing days we did as much as we could to take the mass out of the pistons and the little end of conrods.

Dave

Yes. Many years ago I restored a vintage sports racing car that had the OHV push rods originally produced by a knitting needle manufacturer as they were experienced in making fish bellied rods!

Russell

Thread: Hose thread queery
14/07/2020 16:31:54
Posted by fizzy on 13/07/2020 21:04:01:

well im none the wiser...just read that it might relate to NPT.....who knows?

I'm pretty sure that you will find that the 3/4" refers to the OD of the connector and that it will be 1/2" BSP.

Russell

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