Here is a list of all the postings David Littlewood has made in our forums. Click on a thread name to jump to the thread.
|Thread: Seldom have I seen a more offensive item!|
I think I'd be more embarassed to be seen with the Presley CD (which fortunately is not included in the sale).
Edited By David Littlewood on 12/07/2013 17:57:59
|Thread: Not throwing anything away!|
I just bung the end of the tube on mine out through the cat flap! Of course, the cats are not too pleased...
|Thread: Precision on the Beeb|
Yes, I agree, a hugely enjoyable and educational program. Note part 1 (at least) is only available on iPlayer for another 5 days, I watched it meyself on iPlayer last night having forgotten to record it. Have not watched part 3 yet, but at least I have recorded it.
Should be shown in schools IMO. I do wish there had been slightly less time spent on soulful staring into the distance and more on the nuts and bolts aspects, but then we are all here, I suppose, that way inclined.
On the hand production of the silicon sphere (as a standard kilogram) it reminds me that back in the 70s one of the major Japanese camera companies (I think it was either Canon or Minolta) said that they used highly skilled workers to check the curvature and finish of their glass lens elements, as they were more accurate than machines. Thus this part did not surprise me.
|Thread: Shaping Machines|
0 to 9 embraces 10 digits (sorry, unintended pun).
|Thread: measuring thread depth|
Can't help with the pins, but the tap dimension is not unusual. Many thread forms have a clearance in the root of the female thread in order to avoid the risk of binding. To do this requires that the tap is slightly over nominal size. This is particularly pronounced on ISO metric threads; I don't have details of the BSF thread form to hand, but it doesn't surprise me that the tap is over nominal.
Edited By David Littlewood on 13/06/2013 00:13:07
|Thread: Bulk Metal Removal, Any suggestions?|
Yes, I made one of those for my S7 many years ago - from a Hemingway casting IIRC. Most useful for doing large chunks of iron. Not sure, but it may be possible to adapt it for a Boxford; I'd guess Kirk (did I remember that right?), the new owner of Hemingway Kits would know, seemed a helpful guy when I spoke to him a few years ago.
Edited By David Littlewood on 12/06/2013 16:15:12
Thanks Ian. I have used Mike quite a few times, just wondered if there was another useful source to add to the list!
If I understand your description correctly, you are making a part with a 50 mm spigot 80 mm long, with a main part 160 mm in diameter. I must say if I were making something of these dimensions I would be looking at fabrication - either Loctite or silver solder to fix a spigot in a bored hole in the disc. Much quicker and cheaper. However, I do understand if it's for someone else, and they specified it and supplied the material, you may have to go that way.
Just out of interest - if you know - where did you get the EN24T from? Lovely stuff, used it a few times myself.
|Thread: Wood's Metal/Cerrobend suppliers?|
That's odd (though perhaps not altogether surprising, given the normal paranoia) as bismuth (note - by convention, chemical names are not capitalised) is one of the least toxic, least bio-accumulative of all the heavy metals, and its compounds have been used in medicine for decades (especially in indigestion relief!). Although many of its compounds are toxic in larger amounts (what isn't - sodium chloride is lethal in large enough amounts) the metal itself is considered fairly harmless.
Was there some special reason it was considered unsuitable in your application?
Edited By David Littlewood on 06/06/2013 22:37:53
|Thread: Storing chuck keys|
That rather assumes you only have one chuck.
|Thread: Why is this site's functionality so DREADFUL!!!!!|
I disagree. The Yahoo Myford Lathes group can be a very efficient means of asking and answering questions; it has a lot of very knowledgeable people there, and frankly, as I use it, is far less of an IT pain in the arse than this site software. I use it by having e-mails delivered to my computer; that is a lot less trouble than logging on to the site every time I wish to read stuff. I'm not a fan of Yahoo in general (just the opposite in fact) and I agree that if you only use it by visiting the website it is archaic. The other Yahoo groups I use regularly (Harrison Lathe and 7mm) are also both excellent.
If I had to choose between any of those, and this site, it would definitely be goodbye to you here. Ah, desert island web forums anyone...
|Thread: workshop photography|
Back in the dim and distant past (about 15 years ago) in the later days of film photography, as I was a very extensive user of transparency film, I bought a copy of Wilhelm's "The Permanence and Care of Color Photographs". Rather expensive, but very comprehensive, and with lots of interesting detail about the scandals of mass produced material with very poor keeping properties. If you are interested in looking after old film, try to get hold of a copy, though it may be a bit out of date now.
The gist is that all film material deteriorates, the only difference is the speed. Kodachrome is excellent in the dark, terrible in light. Later E6 films (especially Fujichromes) are nearly as good as Kodachromes in the dark, and vastly better (in fact the best of all) in the light. I switched entirely to Fujichrome...
I do find E6 film is also easier to scan properly. Even using a fairly high level scanner (Nikon Super Coolscan 5000) with special settings for Kodachrome, the colours always seem to come out wrong for me, in a way I can never correct with Photoshop. Maybe I just haven't tried long enough, I just gave up and used a slide duplicator, which worked much better.
Sam, your setup is functionally just the same as mine, just a lot cheaper, and I guess a lot fiddlier (you can't have everything). The only extra function I have on the Illumitran is the contrast control, which helps prevent contrast increase. Even this is a lot less important when the end product is a digital file which you can manipulate anyway.
Edited By David Littlewood on 29/05/2013 13:02:51
I do have a USB microscope, and it does what is supposed to do quite well. However, for vastly better convenience and ease of use (and also much better image quality) you should try using a decent optical stereo microscope. The quality will blow you away compared with any USB microscope I have seen, and you don't need a computer to use it!
How did you go about digitising the Kodachromes? I ask because I recently spent some time doing quite a few of mine; I found them hard to scan (much harder to get the colours to come out accurately) than E6 films. Eventually I found the only satisfactory method was to photograph them using a Bowens Illumitran slide duplicator.
As for the blue tint, Kodachrome is often regarded as an exceptionally stable slide film. This is true is if is kept wholly in the dark, but on exposure to light it is really very susceptible. Even a few minutes being illuminated in a slide projector causes noticeable deterioration.
Not by any chance a 28-135 IS USM is it? Had two, both had the zoom control crap out.
I agree with most of what Norman said above, and you won't go far wrong if you follow his steps verbatim. I do differ in my own practice in a few areas; not that my approach is better, it just suits the equipment I have.
I use a Canon DSLR which is probably wildly over-specified for the job. Since my workshop has no windows, I use flash. I don't find it necessary, or even desirable, to use manual focus unless using a macro lens for ultra close-ups; the AF on the DSLR is sophisticated enough to get it right provided you know how to use it. On flash, I always use a separate (and reasonably powerful) flash - indeed my DSLR does not have a built in one anyway, and they are pretty horrible. The secret is to bounce it off the ceiling and walls behind me; these are painted white - always a good idea, and I used to use it as a darkroom, for which white is the only remotely sensible colour. Using a reflector is much better than direct flash (yuk) but bouncing from the wall/ceiling is as much better again, but you do need a gun witha rotating head, or one which is capable of being held separately.
As has been said, digital pictures are free (well, to be more accurate, they effectively have a zero short-run marginal cost), but they also have the advantage that you can look at the result immediately. With a bit of experience you can soon tell from the review picture whether the focus is sharp and the exposure is acceptable. Even the latter is a lot less critical than in film days, especially if you use RAW files and process later. I find it's rarely necessary to take more than 2 or 3 pictures unless I want a variety for composition.
Edited By David Littlewood on 25/05/2013 17:41:57
|Thread: Parting off problems|
VFD stands for variable frequency drive. It is a box of tricks which is used to drive a 3-phase motor (much smoother and more efficient than a single phase one) and to allow the speed to be varied on the fly (i.e. by twiddling a knob, not stopping to change belts or gears).
I can confirm the the Q-cut sold by Greenwood Tools will fit quite comfortably in a size S00 Dickson toolholder (Myford 7-series size). I can also confirm, as a previous gent said (can't see previous page while typing this) that it's the best parting tool I have used, and I've tried quite a few. It's not just a bit better, it's in a different league; you can easily part off under power, and without resorting to backgear.
It is however vital, whatever tool you use, to get it absolutely perpendicular the the bar being parted, or it will rub on the side as it goes in.
Edited By David Littlewood on 15/05/2013 16:06:31
|Thread: Old carbide tips|
I suppose I ought to put my money where my mouth (finger?) is; put me down for one please. PM me a mail cost and I'll send you a cheque - or PayPal if convenient.
PS - you should try a carbide scraper some time, if you have a significant amount to do; they need far less sharpening than a HS steel one.
Edited By David Littlewood on 14/05/2013 15:05:55
You could make a scraper handle to hold them - rather like the excellent Sandvik one. (Let me know if you don't know that and I'll see if I can find a reference to it, failing which I could send you a photo of mine.)
Edit: just found this reference - plenty more if you Google "sandvik scraper". The tips are £33 each!
Edited By David Littlewood on 14/05/2013 11:44:08
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