Back again!

Good Luck with the new castle Nick! Just watchout for swarf in the bed. I find brass 'needles' the worst. Somehow for me they manage to travel from my shop through the house, up the stairs and into the bed. SWMBO does not appreciate find them! Seasons Greetings

Bob

Does she actually realise the present day cost of brass ?

Keeping it it bed with you at night has got to be the safest place to keep it.

John S.

The price dropped dramatically. So I see no reason to collect the chips in my bed. But cats' hairs seem to be worth collecting, asking my two cats.

Nick

Scrap may have done but new material went up and hasn't moved. Just bought 3 brass disks 7" diameter by 1" thick =A387 EACH.

John S.

ah hark yee olde klieber

Merry Christmas .

Welcome back Nick :-)

When you work out how to scrape dovetails, let us know how it's done.

regards Mark Rand (just starting some dovetails) RTFM

I already know (having made several metres of them). What's your question?

Nick

...ah.. I can scrape them - that's easy. The clever bit is getting them ending up the right size, finish AND orientation! (Oh I can also scrap them )

AWEM

Well, measure in between. :-) Are you talking about a crossslide? Size doesn't matter (almost), equal thickness is important and getting the right angle. The lathe has to turn a bit concave. You could messure the distance of the dovetail to the outer face on both ends (that face the chuck), note them and *then* start scraping. Keeping the two distances at the same difference.

But you can also clamp an indicator to the chuck somehow, put two precise cylinders into the dovetail and rotate the chuck (please by hand) so that the feeler touches the cylinders. Then you know how much you are off.

I also have the original Schlesinger standard that describes all the allowable deviations. If the name "Schlesinger" frightens you (sounds so Krautisch), he left Germany (guess when) and worked in England. Book is also available in English. Worth buying if you get one! And also the book "Machine Tool Reconditioning".

Nick

David Lammas wrote a very simple three part article in Model Engineer - around September - October 1988.

I recall that he covered the treatment of vee ways with cylinders as mentioned.

Of course, those with a surface grinder-- or a Quorn spindle in a mill drill , it's a doddle.

The last bit was MEW and Philip Amos.

I wrote a bit up in MEW about a Myford- but I cannot remember exactly when.

Senior moments, I am afraid

Oh, Nick- none of the Ludwig11 stuff, lakes in Bavaria are cold this time of year!

Cheers

from the other Newcastle- the Brown Ale one

I make that (£87 / (pi x 7 x 7)/4) per cubic inch = £2.26 a cubic inch

That means my circa 2ft long 5 inch diameter hunk of brass obtained for free 15 years ago is now worth nearly 1100 quid.

Be buggered if I'll sell it though as it makes a really good door stop.

Welcome back, my friend. You have been missed!

I'm not desperate at all at my new place. Au contraire, I'm very happy and regret having not moved 10 years earlier.

Nick

Oddly, my wife and I got our 10 year badges not so far away at Berwang, in the Tyrol. The beginning was over 40 years ago. I was 'leg pulling' about the mad gentleman and the castles which were the foundation for Herr W.Disney!

My wife and I spend quite a bit of time in 'the Alps' and have a small place on the French side. I hope that you will have that sort of time to enjoy 'your part'

Norman

Re my "dove-tail-o-meter"[tm] I mentioned: I have posted some pictures in a forum. Here they are:

This is the configuration for measuring (it only compares and gives no absolute size which is not of interest) inside dovetails. The arrangement is a bit exaggerated to show the details. On the left is a knife. The knife has contact to a cylinder that sits in the Vee of the dovetail. The lower end of that knife rests on the horizontal plane of the dovetail. On the right end, we first see a "crow's feet". Like with the knife's lower end, it sits on the horizontal plane. So we always have the same orientation height-wise (good for repeatability ). On the very right end of the ruler is a tiny dovetail (not scrapped, just milled) that holds the feeler gage. You can -and have to- adjust the feeler's ball end to contact the cylinder (in the dovetail to be measured) right in the middle.

Here is the apparatus configured for measuring outer dovetails. Note that the slider with the knives on the left can be flipped over if needed.

And here is the front view:

The whole gadget is constructed in such a way, that precision in manufacturing it doesn't matter. Even if the knife is not dead straight to the dovetail's horizontal plane, it doesn't matter because of the whole dove-tail-o-meter repeatably returns to the same height. Its good to case harden the knife's edge. Once, I'll let nickel plate the whole thingy.

Oh, and I found out, that the slanted guides of the dovetail have to be parallel within at *least* 1/100 mm to get a really good result that doesn't slack on one and and bind at the other end of the travel. I had an different arrangement for measuring inner dovetails that was not precise enough (now in the bin). I only got 1/100 mm readings with +/- 1 digit (that were +/- 1/100 mm). I strongly suggest using a 1/1000 or 2/1000 mm dial indicator and not the 1/100 indicator shown in the photo.

And one more thing: If the adjusting gib is bent, you have to straighten it. Preferably find someone with a surface grinder who knows how to work with bent pieces or take the hard tour and scrap it flat. At tad of a bow (convex to the contact side; maybe 1% of the length bowed, depending on the thickness; if you can't easily bend it flat with your little finger it's bowed too much) is OK, but not as much as I have seen in Chinese dovetails. They bend the gibs to hide their inaccuracy and as a result you'll never be able to adjust the dovetail properly.

Hope that helps a bit!

Nick

. May I add a bit to Nick's excellent discourse?

Like most amateurs, I hit problems in getting to the bottom of the vees in the scraping cycles. The easiest way to get into the corners is to use a hacksaw with not one but two blades to get into the 'female' kerf. In effect, the male edges are similarly 'broken' with a file or scraper.

If, Mark, you have access to a simple surface grinder, it is fairly easy to make a vee jig - and the parellism is assured.

I read somewhere of someone who bought a set of 'references' from bigger scrap lathe to scrape to. It might be far from elegant but somewhere in my dump of metal which I fondly call a workshop is something similar.

But didn't Connolly write something along these lines?

Norman

I found a much better and elegant way. It also doesn't matter how long the kerf has to be and the result will be nothing to be ashamed of:

Take your scraper and regrind the carbide blade (I only use carbide on cast iron). Looking at the flat side, it has to be a rectangle (no radius and especially no rounded corners). On the (normally) cutting face, you have no relief, just straight. Now rotate the scrapper 90° (lengthwise axis) from its normal working orientation and insert the blade -with its narrow side of course- into the kerf. By *pulling* (don't try to push, you might regret the scarfs in the surface when the blade jumps out of the kerf) you can really quickly deepen the kerf or even make a brand new one. If the blade is not thick enough, just rotate the handle a bit. I hold the scrapper with both hands in the lower third, and the handle rests on my shoulder. This way I can apply a lot of force and make lots of chips.

My Vee jig (touching prism) is a bought one. Took 5 months to arrive. 8-/ In the meantime you could also scrap your own one. That had to happen anyway because of the odd angle I needed for my first scrapping "victim".

Nick

On or around Tue, 16 Dec 2008 10:19:22 +0100, Nick Mueller enlightened us thusly:

Blimey, I don't think I can remember how to do that.

Can you imagine how desperate I was? :-) First, I thought that I should have a PCMCIA-card to go into the laptop. Well, where's that thing? Hunt hunt hunt. Right, in the antique Newton (remember?). Ah, Kubuntu recognizes the card. And now for the cable ... hunt hunt hunt ... here it is! Damned, wrong plug at the other end. Now where could be the adapter? Finally got it running. But only for one day, then the card died. Went shopping for a modem. I *knew* that they will stare at me, so I started with "Now for the funny thing ...". The 4th shop had one. But only with a network-connection (it behaves like a DSL-modem, with a little difference that drove me nuts). Took one day to get that thing running ...

Nick