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Member postings for Calum Galleitch

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

Thread: Reproduction ivory look hand grips
14/10/2021 17:06:59

The GPS material Jason mentioned handles very like ivory, but lacks the crosshatching effect of real ivory. There is a rather cheaper material called Arvorin, which is made of resin and available in all sorts of shapes and sizes. It's a bit brittle so needs to be worked with care but does have a more realistic (though clearly not real) effect. White delrin can be baked in an oven and with a little care will scorch to a nice cream tone that can be polished. There is also the Guitar Parts stuff, which now includes Elforyn - they're pretty expensive but very nice and some of their grades are uncannily realistic.

Bone requires a lot of processing to degrease it, and if you don't do it properly it looks fine and then starts sweating fat a few days later.

You can still get actual mammoth ivory, although it's much more expensive and not particularly great quality these days. And if you search popular trading sites for "natural material", you can often find old and ugly bits of sculpture and carving that the world would not miss if they were recycled.

Thread: SKY abandoning their satellite customers
10/10/2021 19:15:17
Posted by Ady1 on 10/10/2021 17:57:37:

sat has got to be the future because they cant wire up the whole world, which would be daft anyway

The interweb consumes vast amounts of energy and resources

Satellite is ideal for broadcast, but less so for internet. My day job involves talking to a webcam all day, and it would be intolerable routed over satellite: you can't do much about the speed of light.

Thread: Indexing Plate
29/09/2021 15:29:41

The photo and drawing linked on this page show pretty clearly how a forked detent works in principle:

You can apply the same logic to your plate.

Thread: Converting fractions to decimals
27/09/2021 23:06:59

Not at all - I have a little app on my phone that reproduces a complete slide rule, with my own choice of scales on it (Infinirule, it's called, for the curious). I even use it every once in a while.

Thread: Heatshrink sleeving as a heat insulator for valve handles?
26/09/2021 13:21:20

Two wee points about heatshrink: one, it only shrinks to about 50% of its size, so it needs to be carefully sized for the part. Second, over time it will lose the inherent tension it has when shrunk, and can slip if it's not mechanically secure.

I'd give the silicon tube serious consideration - it's easy to find in various sizes and colours and should be ideal, I would think.

Thread: The most complex clock built in our lifetime
25/09/2021 14:31:25

In the context of hobby engineering, the question "why" is not a valid one.

Thread: Myford ML7 accuracy
13/09/2021 23:47:20

Cal, it's probably worth saying that cheap Chinese made specialist equipment and cheap Chinese made lathes are not quite the same quality of thing. A lathe is fundamentally a machine that can make machines, and as such it can be altered, updated, improved, in a way that (say) a polishing tumbler or a ring engraver can't. You can with a little effort acquire a very bad Chinese lathe, though these days you'd have to make an effort to do so, but it would be capable of improvement in a way the ring engraver isn't. Many are based on the same fundamental design and they've been making them for thirty odd years.

That said, I think I'd agree about a Taig or Cowells: we often say "you can make small parts on a big lathe", but the truth is it can be a pain and there's an ideal machine size for a given part. Those lathes will be far better machines than the smallest/cheapest Chinese lathes.

Thread: Lathe Vertical Milling Slide
10/09/2021 13:12:44

I think Ade's one is from Warco, and is similar to the ones you see all over eBay, etc.

I've been looking at the topic a little myself, as I'm not really keen on buying a small mill that I will still want to upgrade in any case. There seem to be three routes:

  • bodge
  • buy
  • build

Bodge: I was considering simply bolting an angle plate to my cross-slide, and my compound to that. Unfortunately my compound has a fairly fixed post in the middle of it, the removal of which would be more of a pest than I think it's worth. Acquiring a surplus compound from eBay or the like would seem to make sense, but people want surprising amounts of money for them.

Buy: there are quite a lot of not very good devices out there, all of which I'd need to make an adapter plate for. Obviously a vertical slide is a compromise but I kind of feel all these are a compromise too far.

Build: there have been (at least) two builds in MEW, one recently in 305 and 306, and a bigger, more robust one in 205/6/7. I haven't had a proper look at this last one but just from scanning it looks like a solid machine. I was thinking of modelling it up in OnShape to see how it looks. Other suggestions warmly welcomed!

Thread: I need to cut chamfers into x64 pieces of mild steel - any advice?
03/09/2021 14:49:31

Can you make a jig to be held on the cross-slide, and take it off with a milling cutter held in the lathe? Once you have everything lined up, it should be pretty quick - lock the carriage and away you go.

Thread: Protractors scaled in Radians
26/08/2021 19:16:23
Posted by Bazyle on 26/08/2021 18:20:53:

I've never understood why Excel does trig functions in radians making for an extra calculation instead of providing a straight-up degree option. It must waste millions of man-hours per year around the world.

Well, I suspect the answer is that most of the people designing software in the early days were mathematicians, and so it made sense to make your software that does mathematics do it in a mathematical way. Or, probably more likely, those functions were imported in from a Fortran library, long, long ago and now can't be updated, or everything would break. As an aside, trig functions are calculated in radians, so if you enter anything else it must be converted under the hood anyway.

This may be egg-sucking territory, but Excel has a "named range" functionality, where you can give a grid of cells a name. This grid can be 1x1, and it functions like a programming variable. It is useful for constants like this: you can name a cell "to_radians", say, and then enter your formula as =SIN(90*to_radians).

Thread: Left hand thread on a Chester drill spindle
24/08/2021 17:15:36

Well, having removed the nut, the pulley was absolutely not coming off the cone, so clearly the solution is just to have the nut tight enough! I put it back on and tightened it down with a bit of welly and we'll see how it runs!

23/08/2021 21:14:42

Thanks all - I think Brian and old mart are bang on the money, but to answer your questions: here's the parts from the manual

screenshot from 2021-08-23 20-56-43.jpg

Your can see the relevant parts are 75, 76, and 77. I've had the drill since March, brand new from Chester. It's seen very little use in that time.

To begin with, I had a real problem getting the belts tight enough to not slip under the lightest of loads - I was drilling 3-4mm holes in a bit of cherry and the drill was binding. The belt tensioning arm was quite short, so slipping a lever over it and tightening it up seemed to sort it. Then a few weeks ago it slipped again, which was the first time I discovered the nut had unwound itself. I agree it would make sense if there is any play in the cone then that will be causing bad things; I'll have a look tomorrow and see exactly how it all fits together.

22/08/2021 21:26:04

My Chester D20 pillar drill has a slightly odd construction, and I'm not sure if I'm missing something or the drill is!

Viewed from above, the drill spindle obviously rotates clockwise. The pulley wheel sits on a tapered cone that in turn sits on a keyed shaft that drives the whole spindle. The pulley wheel is held down by a thin nut (like an old-fashioned jam nut) that screws onto a thread, pushing the pulley down onto the taper. So far, so reasonable.

However, the thread is a left-hand thread (it screws on counter-clockwise from above), so the natural action of the pulley is to push up off the taper and then to unscrew this nut. The first time it happened, I didn't really think it through, I just assumed it hadn't been tightened properly to begin with. It happened again today and I don't think there's been five minutes of operation time since I last retightened it.

Am I doing something wrong here? Is there something missing? I don't understand why you'd specify a left-hand thread without good reason, so what's the good reason?! Should I just find another nut and lock it down?

Thread: equation editor
09/08/2021 00:09:18

It's a good example of making the simple things hard, but the hard things possible. The LyX frontend, by the way, is somewhere between WYSIWYG and screenfuls of code. The equation editor in particular is now very easy to use.

Thread: The shed may not be dead!
06/08/2021 13:13:12

Just out of interest, Neil, has it been reflected in subscriber numbers?

Thread: Pythagorean Triples in Babylon !
05/08/2021 15:19:43
Posted by Kiwi Bloke on 05/08/2021 11:26:15:
Personal realization was trying to get to grips with musical notation, as an adult. It's a disaster!

Hmm, well. It's very easy to invent a notation system for music that is easier to understand; it's far harder to invent a notation system that accommodates extension as Western notation does. Many of the advantages of music notation as used in the West are only apparent to relatively expert musicians. And it is far simpler to learn to read than written English.

Thread: equation editor
04/08/2021 14:52:34

The program I always turn to for mathematics typesetting is LyX. It's a front-end for LaTeX, and it can do more or less anything LaTeX can do, sometimes more easily, sometimes less. I haven't used it to generate individual images for insertion into Word, but I would think it's possible. At worst screenshotting would work.

Also, w3c maintain a list of MathML editors here:

I don't know how well any of them work!

Thread: Install & commission of a Chester Cub 630 (Warco GH750)
03/08/2021 15:04:25

Surprisingly difficult to find an 11mm chuck key, but I did find a 7/16" key which needed just a hair ground off to fit. And, with a good bit of force, and an extremely alarming bang the camlocks came loose. I got the chuck off, and like everything else, it looks suspiciously like the original factory grease.

I mounted the four jaw up just to see that it fitted, after all that, and it does - just. The jaws will hold quite a large workpiece without protruding beyond the chuck anyway but without doubt one could accidentally do a great deal of damage if they tried!

Thread: Paypal payment delay
01/08/2021 14:44:10

I think it is also to do with whether or not the transaction has cleared. When you buy something with Paypal, it takes several days for the transaction to clear, and if it's stopped in this time it's unwound, like it never happened. Once it has cleared, it has to be unwound with reverse transactions - which would also explain Robin's experience!

Thread: New idea of engine and security window idea
28/07/2021 21:45:16

Hello Daniel and welcome.

The first thing I would recommend you do is research and understand the law around "intellectual property". There are several different types: copyright, patent, trademark, and so forth. It's important when you're working with a potentially valuable idea that you understand what the legal protections you have and can get are. In particular, you can't copyright an idea: copyright is complicated, but it only applies to something that actually exists.

I don't know much about steam engines (or window tinting, for that matter), but one think I can tell you is that in general, ideas aren't the tricky bit - the tricky bit is (a) turning it into a working design that can be manufactured, and (b) selling it.

A good starting point might be to create a computerised design, using a package like Fusion 360 or OnShape, so that you can work out what will be involved in making your device.

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