Member postings for Mike Crossfield

Full details and much more besides are in GHTs book "The Model Engineers Workshop Manual". If you don't have this I can't recommend it highly enough.

Otley. Interested to read about your conversion. I can appreciated the theoretical benefits, but do you find that there is a noticeable performance improvement? If so, some further details would be appreciated.

Mike

-most enjoyable programme. Very nice to see a Myford Super 7 of the same vintage as my own being used.

Mike

Entex has a very impressive catalogue. However, like other major suppliers they are not interested in supplying small quantities. I recently needed a single special spring, and after working out all the details, rate, initial tension, extension etc found just what I needed in the Entex catalogue. Price was a mere £1.80. Problem was I would have had to buy 25 and pay a hefty postage charge. Effectively £50+ for 1 spring!

If you haven't already seen it, there is a decent write up at www.lathes.co.uk.

Mike

Tony

If you haven't already seen it, there is some info in the archive at lathes.co.uk.

Mike

Well, I think my questions have been pretty comprehensively answered!

Thanks to everyone who responded. I was particularly impressed with Andrew's detailed test results in his linked thread.

Just need to digest it all and do some tests of my own now.

Thanks Raymond. I wasn't sure if there was some non-obvious reason for not using GT inserts on steel, but it seems not.

Mike

That's good information.

Many thanks Thor.

Mike

After many years of using only HSS tools in my home workshop I have recently been spurred into trying carbide insert tooling by posts on this forum. My first tests with polished TCGT inserts were very encouraging indeed, and for finishing cuts on unleaded mild steel i got a better finish than I have ever seen with HSS. However, I'm aware that polished TCGT inserts are intended for aluminium and plastic, so I would be interested to know what the issues are in using them for cutting steel. I have tried coated TCMT inserts, but I can't take cuts as fine as with the GT inserts, and the finish is not as good.

I would also appreciate some guidance on what cutting speeds to use with carbide inserts (TCGT or TCMT). Can I just use some multiple of the speed I would use with HSS for the same task?

Neil

I think your maths has gone astray. A 6 inch hss fly cutter should, I think, be run at 60 rpm max, not 1 rpm.

Mike

Jim

5 years ago I was looking for a first clock, and chose Colin Thorne's Skeleton timepiece. It was enjoyable and pretty straightforward to make..It looks very good under it's glass dome, and keeps time to about 2 minutes a week. You can buy the basic plans quite cheaply, but it helps a lot to also buy Coiin's book on clockmaking for model engineers.

Mike

Well, I ordered up the micro polished inserts as used by John yesterday, and they arrived today (great service from APT). I set up a 5 inch length of 1 1/2 mild steel (unleaded) round and took a roughing cut to get it running true. Took a couple of 2 thou cuts with a very carefully ground and honed HSS knife tool. 250 rpm/2 thou per rev feed. Finish was what I've come to expect - rather similar to John's second photo. Switched to the micro polished insert and took another 2 thou cut. Very pleased to say the result was excellent. Significantly better than that achieved with the HSS tool. Played around a bit with speed, going up to 400rpm and down to 150 rpm (lathe has VFD) but didn't seem to make much difference. Slight improvement brushing on some neat cutting oil. Doubled the feed to 4 thou/rev. Hard to see a big change. It was quite noticeable that with the HSS tool the swarf came off in long stringy threads, whereas with the insert tool the swarf was in tight curls, and noticeably wider.

Didn't explore different depths of cut since there was so much material extending from the chuck, but I would be interested to know what depth of cut would be ok with these inserts. They are supposedly intended for Aluminium, so I wonder how they would stand up to heavy cuts in steel.

My lathe, by the way, is a carefully set up Myford Super 7. The topside is set slightly stiff, and is normally locked anyway. The cross slide is silky smooth moving - probably a bit too free - but has absolutely no trace of shake.

Mike

Andrew has it almost spot-on. One small detail wrong - the box of diamonds was concreted into the hull of the boat, and after being salvaged was then hidden in the engine sump.

Absolutely cracking good story. I've re-read it several times, and it always bring a smile to my face.

Mike

I've just ordered the ones detailed by John from APT, so watch this space…….

Mike

Thank you for the info. I've always resisted insert tooling except for roughing out cast iron, but maybe it's time to resist my prejudice!

Mike

John

Mighty impressed by the finish in your final photo. Can you give some details about the indexable tip you used? I want one!

Mike

If your cross slide dial is slipping when you turn the ball handle it can only be because it's rubbing against the end bracket. This seems to be confirmed by the observation that it doesn't slip when you turn the handle the other way - presumably the backlash is moving the dial just clear of the bracket when you wind the slide outwards.There should be visible clearance between the dial and the end bracket. If you don't have this you may need to skim a couple of thou or so off the back face of the dial. HTH. Mike

- problem with the old 3ltr V6 Ford set up was when the tufnol gear became brittle after a few years, then disintegrated under load. Ask me how I know……...

Mike

As is sometimes the case, this thread has gone off in a direction of its own.

When I started it, as anyone who reads my original posting will see, my intention was simply to warn the unsuspecting that a fake product was being passed off as the genuine article on Ebay, and to offer some advice on spotting the fakes. I thought I was being helpful, and certainly not "whinging".

I particularly wanted a Mitutoyo product because I appreciated the functionality and quality. Yes, I was looking to buy at a good price, but I think it's offensive to call this greed. Don't we all shop around, particularly when making a significant purchase? The description of the item gave every reassurance that the item was genuine, and the £50 price was not implausibly cheap. As it happens, after my bad experience I bought a genuine item from a UK source for a similar price.

Mike