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Member postings for Bill Davies 2

Here is a list of all the postings Bill Davies 2 has made in our forums. Click on a thread name to jump to the thread.

Thread: Vacuum Pump Advice Please!
24/09/2020 19:37:54

Do you need a 'high' vacuum Dave. The vacuum pump I used as a school technician would remove enough air that a buzzerl was all but silent, but would be nothing like the vacuum required for making bulbs, electronic valves (tubes), sputter aluminium onto mirrors or the like. I can't recall the pressure that it went down to, but a surprising amount of air had to leak back into the bell jar when the valve to the atmosphere was opened.


Thread: Spindle Speed
24/09/2020 19:03:00

Ooops, added to the earlier thread; go up the page!

Bill, blushing.

24/09/2020 19:01:08

Found this on our website:

Strobe disks

Go down the page.


Thread: What sort of light source to use a strobe disc?
24/09/2020 18:54:37

LEDs will work, depending on how bright or how large an area needs illuminating. But I've use printed strobe disks to check the speed of my mill against multiples of the 50Hz mains.


Thread: Steel stock for newbie ???
10/09/2020 21:48:44

Strictly, Ian, the EN series is obsolete (introduced during WW2), but EN1A is the weakest of the mild steels. It is offered with and without lead, and the leaded version must not be welded or brazed, as it formed a weak joint. Both machine well, especially the leaded variety.


Thread: Surface gauge reconditioning
11/08/2020 09:19:48

Or even a bit of firm polishing with green 'scotchbrite' scouring pads. If case hardened, the case may not be very thick.

Thread: Arduino low power alternatives
06/08/2020 20:02:48

Unless things have changed, you would need to burn a bootloader onto blank atmega328 chips and the like. I've used a few with very few external components (crystal, ...) on veroboard, but not recently.

Thread: Basic Electrics
13/07/2020 16:02:17

Alan's comment reminds me of the 'gut-buster' power drills used where I worked for drilling holes by hand on top of 20 ton castings. Big motor, a pipe handle sticking out on each side, usually a two-man job. I can't recall what make they were, but I imagine there was a genuine risk of rotating the operator !


Thread: Myford chuck not gripping
10/07/2020 19:33:44

Perhaps the scroll needs some lubrication.

Thread: Gear software
19/06/2020 14:10:53

To show it's not too tedious to draw the curve, here's part of a scan of an A3 drawing I made a few weeks ago to give me some idea of the error between a circular arc and an involute, so I haven't actually drawn the involute, just tested various radii to detemine the fit. It's not very clear because the pencil drawing was quite light; I've attempted to increase the contrast. The scan is in my album.



19/06/2020 13:52:45

Perhaps cut a base circle from plywood, plus a length of string and a pencil, which would provide a suitably accurate involute for this project. Or even get the long-unused compass set and protractor out, and draw it.


Thread: Mono or Multi tube water heater
19/06/2020 13:46:59

Interesting problem, raise a body of water to temperature, and simultaneously stabilise it against heat losses. A a general rule, gas is one third the cost of electricity generated from gas, due to conversion losses.

Dave's comment is interesting,regarding solar. Assuming direct solar heating, we've all felt the heat of water from a hose pipe on a hot day. But how doable? Today, in Cardiff, it's cool and overcast, so it depends on where Fizzy is located.

What's the power of the electrical heater?

Thread: Questions about lathe power feeds.
06/06/2020 16:23:56

Clive, looking at, the Ikegai A-20 (for example) has some very nice features and seemed to incorporate these quite early on, including the recirculating ball leadscrew. But then it is described as a toolroom lathe.

It almost breaks my heart to imagine what it might have cost new, and after a google-search to see the second-hand prices at the end of its life.


06/06/2020 13:23:54

The reason that the rack is used for sliding feeds is to preserve the accuracy of the leadscrew for threadcutting. Many of us are familiar with a lathe or mill's screws being locally worn. Apart from small 'amateur' lathes, even lathes produced for training or light engineering purposes had a separate feed bar usually driven from the gear train that drives the leadscrew, or a keyway cut along the leadscrew to serve the same purpose. Clive's point above about doing it right, I take it to mean using current technologies of recirculating ball leadscrews or other methods causing less wear of the leadscrew.


Thread: Soldering Iron
05/06/2020 00:46:44

Why North Americans call it 'soddering'? - possibly a French influence. Solder is souder, both soft and hard, and I think the word is used for weld as well. A quick search finds old French spelt it 'solder', but ultimately it's from Latin 'solidare,' meaning to make solid.

On the other hand, perhaps a desire to differentiate themselves from 'native' English (can of worms) or more likely, the Americans speaking the King's English and we've (meaning the Brits) moved on.


04/06/2020 01:11:07

I recognise speedy builder's problem with cold pvc leads. Antex also provide their irons with silcon leads, which remain flexible when cold, and are not damaged by accidental contact with the hot tip. Over time I have replaced my irons with these versions. The leads are also available separately. No connection, just a happy customer.


Thread: Help identifying collets
29/05/2020 23:00:59

I think they are 3C collets. The CC indicates that they were made by Crawford, and the 327 I think signifies 3C.

Crawford Collets is now part of the 600 Group, a long established group of British machine tool manufacturers.


Thread: Stabilising a Milling Machine
19/05/2020 14:05:00

Lee, I have the similar Wargo GH (geared head) Universal mill. Mine sits on a wooden stand, which in turn sits on a wheeled base I bought at the time to help me manipulate the mill around a small garage.

When I bought mine, Warco was out of bases. I was later delivered the next size up, and I wish I had your one. I have kept the wooden stand as it is a better height for me I don't like stooping.

From my experiences with the wooden stand, I don't think it's possible to destabilize 300kg of machine, even though there may be some wobble and vibration. Heavy stone structures withstand a lot, often even earthquakes. I look at buildings and marvel that they stand, yet I understand cognitively in which direction the forces are going.

If you can raise it up again, some rubber might kill the vibration, the wobble is due I think to the thickness (or otherwise) of the stand, but I don't think you need be concerned.


Thread: Unknown tool
17/05/2020 19:32:50

Or for a star wheel dresser for a surface grinder? Is the base of the block ground flat (and magnetic!)?

However, I've only ever seen surface and cylindrical grinders dressed using mounted diamonds, which I occasionally use on my 6 inch bench grinder.


Thread: Box-Shifters and Quality Assurance
12/05/2020 11:18:45

Michael's comment reminded me that the Sinclair scientific calculator was the first one I bought. Shame the trig functions were inaccurate, so it was of little use to me as a young engineer. I expect it's still lurking in a drawer somewhere, unused. I see that someone has reverse engineered it:

Sinclair Scientific

I also bought several other Sinclair projects, before I learned my lesson, including a stereo amplifier. It never worked. I was never as impressed by Sinclair as the Press seemed to be.


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