Member postings for David Littlewood

Graham,

Have a look at **LINK**

Should cover most machines.

David

Alan,

The reason why several of us have suggested gauge plate is partly because it is hard enough to stand up to a fair amount of wear, even without being hardened - but mainly because it is dimensionally very accurate. Most metal sections of a more mundane pedigree are often not too close - mild steel, for example, is often a couple of thou undersized, and also can be not as crisp in its cross-section. The only way to get it spot on is to start with a larger section and mill it down to size - and then (with bright sections) you can run into problems with distortion if you don't stress relieve it first. Black MS is rather better in this regard.

Of course, one thing for you to check is how precise is the section of your plastic. If that is slightly under nominal size, then you might find MS or aluminium in commercially available sections would be OK. MS would probably survive a few hundred holes without hardened bushes, if you are careful; aluminium probably wouldn't.

I have a miiling machine with DRO, but I'm too far away from you; I really think you need someone close so you can get together 2-3 times to get everthing checked out.

One afterthought - you might like to consider adding a metal section - say 6 mm square - at the base of the jig so that you can hold it in a machine vice without obscuring the holes or the slot for the plastic sections. As designed, you may have trouble in that respect.

David

Edited By David Littlewood on 24/11/2012 19:16:02

Alan,

OK, I get it. Yes, I see a jig would be necessary. I also agree that gauge plate would be the ideal material. If I were making it though, I wouldn't use a hockey stick shaped spacer; I'd use a simple rectangular piece with a separate end stop. I would dowel and fit the parts together with cap screws (counterbored to sink them below the surface), then make the holes with the jig assembled, using co-ordinate drilling from a reference edge.

So, you need to find someone who has a milling machine with a DRO - a bench drill would be possible but there would be too much marking out and increased risk of errors. I suggest you take a piece of the plastic to be drilled, to make sure it will fit neatly in the jig.

I haven't grasped what the extra little bit is supposed to do - presumably some kind of packing to hold the plastic in the jig, but perhaps you could clarify.

You didn't answer the last question I asked - where are you based? - as you are far more likely to get help from someone just down the road than someone 800 miles away.

David

Edited By David Littlewood on 24/11/2012 15:57:57

Alan,

It would help if you told us what you are trying to make, what are you making it from (i.e. the material) and (equally important) how many items. How precise do they need to be?

The "how many" question will guide the decision about durability of the jig (hard bushes etc) - or even whether you need a jig at all: if you just want a few, then coordinate drilling using a DRO could be the best route.

Also, what part of the country do you live in - if someone is going to help you, face-to-face would be best.

David

Edited By David Littlewood on 24/11/2012 13:13:57

Ian,

ISTR that during WW2 Stuart Turner made some steam engine generator sets for SOE operatives to take to France so that they could power their radios in locations remote from any power supply. From memory of the photos I saw, they looked very similar to some of the current range of verticals (not the tiny ones obviously).

Also, some of the larger verticals are specifically sold as being capable of powering sizeable boats, and I think there are some on Windemere (or therabouts) which do actually use them.

David

Siddley,

Just a minor pedantic correction: it is still legal to own self-contained air cartridge weapons (SCACs, aka "Brococks" ) in the UK provided that you owned them before the ban came in and you got them put on a firearm certificate before then. You are not allowed to sell them or give them away (you can't even leave them to your descendants in your will). I'm not sure what can be done with them (legally, I mean) though I can't immediately see anything in the legislation that stops you exporting them for sale abroad....

David

The bloodly smiley appeared again! I got rid of it by putting a space between the " and the ).

Edited By David Littlewood on 19/11/2012 23:03:38

Robin,

Your other option is to tailor your activities to suit the space. If you made something like small stationary engines, or Gauge 0 (or even gauge 1) locos, you could do all that on a micro lathe, which you could easily put on a board and use in a spare bedroom or dining table (with appropriate permissions of course!). A Unimat or Taig/Peatol size would be easily manageable in a flat. That would give you a few years of experience, then when you have more space you would have a better idea of what your interests wer, and what to buy.

One of my fellow Gauge 0 Guild members does some fantastic work on a Unimat inside his home.

David

Simon,

To add to the above, all of which I agree with, if you find a decent Super 7 at a price you can afford, it is a decidedly superior machine. Among other things, it has a more robust headstock spindle bearing, a countershaft clutch, a longer cross-slide (useful for milling), a far superior topslide design (the ML7 one is particularly inept as its rotation is limited), re-settable dials, and a leadscrew handwheel (an order of magnitude more accurate for setting the saddle).

Oh, and one other important thing to look for, whichever model you are contemplating, examine the inside of the headstock taper carefully. Having made sure it is clean of nasty sharp swarf (and if the owner leaves swarf in there it is not a brilliant sign), carefully stick you finger inside and rotate. If you feel any scoring or roughness it is a sign that the taper has been abused quite badly, and as it is hardened it is virtually impossible to cure. The tailstock taper is less crucial, as (a) they are not hardened, and (b) in the worst case, they can be replaced without too much difficulty. They are also far more likely to suffer scoring from tooling which loses its grip (mainly drill chucks) and it isn't quite as much of a black mark against the owner

David

Edited By David Littlewood on 14/11/2012 12:08:27

Doug,

(1) No, I have only used it for carbide, though I might use in on HSS if it happened to be on the grinder if I needed to do a light-ish job.

(2) No, at least I have not found it necessary with the cup wheel I have used, provided you take care to get it as accurately centred on the spindle as you can.

(3) I have not done a detailed comparison, but I would say it is comparable to the finish from a fine alumina wheel.

David

Doug,

I have several diamond wheels, bought from Arc Euro Trade. They are excellent for sharpening tungsten carbide - vastly better than the old green grit wheels - and are very reasonably priced. I recommend you try the cup or dish types for most tool sharpening, they have a flat face.

David

Jason,

Thanks for the suggestion, but I already had compatibility view on and the problem still exists; in fact, turning it off makes it much worse. Does seem though that I owe an apology to spotty youths as the explanation suggests it is Microsoft's fault. I should have known!

David

I know several people have said it works OK in Firefox - but I really don't see why I should change my browser (IE8, as it happens) just because some spotty youth doesn't know how to code a website!

David

Edited By David Littlewood on 06/11/2012 14:26:23

If you are going top tap the work to true it, I recommend you use a copper/hide mallet - it's much less likely to mark the work.

If you can afford it*, a Griptru chuck can be adjusted to make the piece concentric.

If the work is small enough, a good quality collet chuck will give a much better concentricity, and with far better consistency between workpieces, or on replacing the same piece.

BTW, the correct name of the chuck maker is Burnerd, not Burnard. Might help if you are searching for one, though perhaps best to try both, as so many people get it wrong.

David

*If you need to ask the price, you can't afford it!

Edited By David Littlewood on 06/11/2012 12:05:21

One issue I have experienced with knurling is shifting of the toolpost. Knurling places much greater sideways pressure on the tool, and this can cause a shift unless you are prepared for it and make doubly sure everything is tight. I find a Gibraltar toolpopst is best.

My reading of this thread has been completely spoiled by the b****y adverts down the right hand side. Is anyone at MHS interested in making this s****y web forum software work with any semblance of normality? It's by a country mile the worst I use.

David

Chris,

As another alternative, you should consider looking for a decent second hand T&C grinder such as a Clarkson; you can often find them at a price which is lower than the alternatives you mentioned. Also, be aware that without add-ons many T&C grinders will not sharpen twist drills in the conventional manner - though they can usually do them using the 4-facet method, which has advantages anyway.

David

Just a thought, if someone wants to try some experimentation: try electroless tin plating the brass. I have done this a few times, it almost instantly gives a coat of tin several microns thick which seems to adhere well. I have not tried painting it, so you can do your own testing! Available here: **LINK**

...but you can make up the solutions yourself at considerably lower cost.

David

Terry,

My understanding is that the Spitfires generally took on the Luftwaffe fighters, and the Hurricanes saw to the bombers - at least that was the plan, I'm sure it didn't always work like that. The Hurricanes were a very good stable gun platform but at a disadvantage against the fighters as they wer less nimble. Good partnership.

I take it that's the new apprentice?

David

Johan,

I think (and I could be wrong) that when you post pictures side-by-side, as above, it makes the text for the whole of the page extend sideways so that the stupid advertising panel hides a chunk of it. Yes, I know, even the average 10-year old could probably design a web site less cack-handed than this one, but still, it's kinder to all of us if you just try to post them one above the other.

David,

Any chance your web people could .... no, I suppose not.

David

Edited By David Littlewood on 23/10/2012 10:40:10

Any language where the definite article has three genders, a plural, and four cases has to be considered weird IMO. And don't get me started on compound verbs and word order!

David

Terry,

My experience exactly matches Jason's. I fitted a DRO system (from Allendale, who I found extremely helpful) to my milling machine about 4 years ago, and now could not imagine being prepared to put up with a mill without it. It's extremely useful for milling, but it's absolutely indispensible for co-ordinate drilling.

I contemplated putting a similar system on one or both of my lathes, but somehow it has never seemed quite so important - I'd still want to test diameters in the traditional way, and the leadscrew handwheel on my S7 has always been perfectly good enough for turning up to a shoulder.

In theory you could share a console between the two, but it really isn't worth it as Jason said. The fitting of the scales themselves is quite critical, and they realy have to be dedicated to the machine they are on, so the saving would be minimal anyway.

I have looked with some bewilderment at those DRO systems which work by measuring the rotation of the leadscrew (the ones that look like overgrown handles), and I really can't imagine why anyone would bother. Unless you have a zero-backlash system fitted (which probably cost more than the DRO) then they simply cannot handle backlash, and therefore would seem to me to be worse than useless.

David