Member postings for Mick B1

Well, thanks again for that table, Paul - I've saved it and printed a copy to put in my manual.

I have found that threads I've cut as above - using the gear settings in the manual - have fitted existing components quite nicely, but I'll certainly use your table if I come across pitches not in the manual.

There are two shearpin issues I've come across, both resulting from errors of mine, that it's as well to be aware of:-

a) The leadscrew shearpin on mine (just right of the sleeved flange where the leadscrew drive comes out of the headstock) was made of not-very-mild steel, and failed to shear when I engaged the wrong feed by mistake, resulting in a bend in the apron pinion (or its shaft) that drives the saddle feed. I was able to straighten it, but lived with tight spots for over a year before I found a way to do that. I then replaced it with brass.

I had a chance to examine and test the very similar (and more recent) Chester DB10VS a few months back, and it looked as if it had a brass shearpin in the analogous position, so the factory where both machines probably originate may have done a change here.

b) If the crossslide leadscrew shearpin (which is brass) breaks, it's likely to fall into the apron gearbox, and you'll likely need to take that and the longitudinal leadscrew off to get out the broken bit - which in my case jammed the gearbox most perfectly!

Both of these issues could be fixed with no lasting damage once understood.

I think this too. I've been using a Metric WM250V for about 8 years now, and the screwcutting I've done has been mostly threads for railway parts where the Imperial pitches I remember have been 11, 14 and 19 TPI. As far as I remember I couldn't find another lathe in their workshop that was listed on its plate to do 19 TPI.

Frankly, I think the threading dial Warco have put on there is probably just to satisfy a marketing requirement that there be one visible to the punter as they make up their mind to buy, irrespective of whether it's any good, which I suspect it isn't. It's a helluva lot safer and simpler to just keep the nut engaged and reverse back, and unless you're doing a long thread for a time-deadline, that's not much of a problem.

I have generally a pretty high opinion of the 250V. It doesn't have the power of the industrial lathes I used for my daily bread in the 70s, but OTOH that's also saved me a few broken tools. It's quiet, smooth, versatile and reliable - the only problems I've had have been of my own making, and fixable.

Thank you for the links to off-table pitch gear calculation routines - I haven't come across requirements to do any such yet, but of course it's possible I may.

I did a PMR 7 some years ago. I did all the machining on a Myford Speed 10 with a double-swivel vertical slide to do the milling and co-ordinate drilling.

The valve timing was a bu99er to set up, and I thought for ages that I'd made some fundamental error, 'cause I couldn't make it work at first. But I made another attempt more recently and finally got it right!

PMR-7 running

So, as long as it can rotate freely, keep at it till it goes!

Edited By Mick B1 on 14/04/2023 11:06:18

I used the same for 45° milled chamfers. For a long time I had an old slot drill that I'd ground to a 90° point with clearance behind the cutting lips - that worked well, also for countersunk slots and suchlike, but I lost it sometime in the last 20 years or so.

I'd make another, except I don't currently have a good enough reason to repurpose a decent slot drill.

But many cars are needed to do more than commuting. I don't want to arrive in Dartmoor or The Lakes from the Midlands with a near-exhausted battery, and then have to join a queue to spend hours recharging.

Last year we went to Orkney, which needed a 400 mile trip each way to Aberdeen, and a couple of hundred more miles touring. That'd be considerably more difficult and time-consuming in most current EVs. Right now I can put in over 500 miles' range in a few minutes. I'll be interested when I can buy a lowish-mileage but several-years-old EV that can deliver comparable performance for a modest SH price.

It's a stand for a soldering iron or a pyrography pen (which is almost the same thing), almost invariably sold bundled with them.

You bend the 'Y' up to make the cradle for the tool - usually the barrel of the soldering iron.

Doesn't look like your dad ever used it - he might've had some other rest, or not used the iron much.

Thanks for that, I get that now.

Though I paid what seemed a sensible and very moderate price for my low-mileage but (at that time) 9-year-old Touran - and a practical workhorse it has proved to be.

I think I'm the only one mentioning VW in this thread, and I don't know what that's supposed to mean. It doesn't make any sense in my knowledge of German.

I've had various estates over the decades, including Mondeos and Focuses, and they all worked. I'm happy now with a VW Touran. It's moderate on footprint, economical, reliable and spacious. What's not to like?

What about bridges, car ferries, etc., if a similar volume of traffic weighs 50% more?

They need to remark car parking spaces anyway - some I know look as if they were designed for 1960s Austin A40s and 1100s.

Exactly. A colleague at work had a similar attempt made on her handbag in a Redditch car park over 20 years ago. She wasn't aware of the cut till much later. The bloke got a packet of Polos, but failed to release her purse.

Me too, 'cept I never thought of the newspaper, and it doesn't seem to matter much if you don't get greedy.

You can get away with weird stuff, like chucking a boring bar with a long (carefully-set) toolbit to cut the internal radius on a ring-reinforce for a hypocycloidal engine...

Finished some smokebox door hinge pins for the railway's S160s, and last week delivered them the last of the lubricator union nuts.

I measured the pins already in place at 19,55mm dia, so made the new ones to that. The parallel portions are 4.1" long, and are indeed parallel within < one tenth for one of them and about 2 tenths for the other. Considering the WM250V was just plonked down on the garage floor by removal men 2 years ago, and hasn't been levelled by anybody's dad's method, I think that's OK.

The lube union nuts are for a 5/8" shank cone into a M20x1,5 threaded spigot. Mercifully the railway have a plug tap that size, or I'd still be on it now if I had to screwcut 'em. They wanted 32-off, which is a bit of a tedious task for a volunteer on a plain centre lathe - I couldn't go much faster than 2 an hour - so I was on it in spare time for a couple of weeks. I'm trying to instill the idea of them getting a smallish capstan for this sort of work.

Then I found I had a bit of 1" AF Hex phossy bronze left over from some other forgotten job, so I made an extra out of that for fun, for my sample shelf.

Edited By Mick B1 on 02/04/2023 16:32:12

Me too. I spent nearly 40 years in various contacts with engineering personnel from Cornwall to Dundee and never heard the word in any other context.

I used a wipe with meths followed by a hot wash in washing-up solution, then apply the bluing with a soft paintbrush while the metal's still hot. Wash again (in rubber gloves), dry, and oil up when happy.

Edited By Mick B1 on 31/03/2023 12:19:48

As a kid I knew the son of the builder who put up our house. He completely dissed Bayko sets with their vertical wires and slide-on wall sections - it was nothing like the way you built *real* houses, he said.

I suspect his dad was quite a traditional builder with a low opinion of the prefabricated techniques used by some sections of the trade.

I used G96 cold blue 'creme' (fancy word, I'd call it a paste) on the naval cannon in my pic album, in 2005. It still looks the same now AFAICS, with one light touchup at some date in between.

Well, you've picked a considerable outlier to the normal range of model engineering components, in size, difficulty of material and cost . So, is powered partoff just another extreme sport?

My own view is that manual feed provides a flexibility, and an awareness of any issues developing during the parting cut, that I don't think you'd get from doing it under power.

The biggest, thinnest thing I can remember parting was some side flanges for toothed-belt wheels I was making for a subcontractor to Ford's toolroom in the late '70s. I had the dishing problem I mentioned above, and sorted it with light facing cuts in soft jaws. Can't remember whether I lost one through not having left enough excess, but if I did I had enough of the 5 or 6 inch bar to replace it.

But hey, as is often said on here, no-one can tell anyone else how to do summat, only how they think they'd do it.

And yes, with material like that and a tight quantity, sooner thee than me!

In deep parting cuts, angling the tip can also bow the blade sufficiently to concave and convex the sides of the parting slot, even on softer materials like acetal/delrin. That may mean an extra facing cut on the bar end before machining the features of the next component. You have to balance that against any advantage you might gain, such as a clean cutoff of the parted component, if it's small enough and has a through hole. Horses for courses.

I'm not bothered by return fire . I can't see a practical role for powered partoff in the sort of quantities typical in model engineering, and where other parts of the cycle aren't also automated.