Member postings for Mick B1

Well, if I'm remembering the conventions I once used as a Tool Designer, that 7,2 rad is thrown from the CL of the boss,and there's only one way to read it.

You're quite correct that the milled flats on the mating shaft leave a narrow line of turned diameter on the 'corners', and that might leave theoretical scope for milling the hole (as in eg. Blowlamps drawing), but with the boss being 22mm thick, trying it with a 2mm dia. endmill doesn't look an attractive proposition.

I've shaped out keyways and square corners before using the carriage handwheel, but with a dozen to do I'm imagining the blisters already...

I don't think I'm gonna be doing it - but I think it'll be easier to lash up some sort of fixture to set the angle so that a welder of normal skill can add the handgrip, than to precision-weld in a segment with an inside radius. The angle needs to be maintained within a degree or three, because in some applications the valves are ganged together in some way I haven't seen, and need to operate together.

The dimensions are basically a clearance fit on the milled and turned shank of the valve shaft. I don't know whether brazing would be strong enough - the welded-radius suggestion came from a very experienced locomotive fitter, but I'd rather make it in one piece as that removes any question, and looks like the original handle I'm wanting to copy.

Arranging spark-eroding would certainly be expensive and probably be more exhausting than filing/shaping out a round hole.

Thanks for the suggestions, fellas, but I'm wondering whether anybody actually knows, so likely I'm gonna hafta try it...

Edited By Mick B1 on 01/06/2023 22:28:15

I was thinking of a slot drill a bit over 12mm, fed over by about 1,2mm to elongate, and touch the rad inside. Still means there'll be more to take out where the rad corners out to the parallel faces than there is in the square corners.

A multistep broach looks a lot more complicated to make.

The angle can be set when welding the boss onto the handgrip part.

I've an 'ole to make in a valve 'andle boss, like this:-

I've a dozen to make, so I don't want to be filing out the radius and corners. People have suggested milling out a 12 mm wide slot in the bar the bosses are made from before parting, and then welding in a segment of a matching disc with a 14,4mm hole in it - but I've done no more than a couple of hours welding in 73 years.

So I'm wondering if it'd be easier to buy/make a rotary broach?

...and could it make such a hole?

...or does it require balanced material removal all around, as in regular polygons?

There was a related issue with the 'Any Elevation' loading system originally fitted to QE class 15" battleships. The idea was to raise the rate of fire by omitting to depress back to level or near between rounds. However, under severe manoeuvreing conditions, as in battle, hydraulic power to the rammers might be starved, and when working at a high 'uphill' angle with a 1938 lb projectile, the wring of the driving band into the rifling leed could fail and the projectile follow the rammer out on withdrawal. The wring could also potentially fail through vibration after the propellant bags had been rammed, which would be much worse still.

I understand that, rather than modifying the equipment, it was decided simply to resume the operating practice of depressing the guns for loading, but to a wider tolerance than before of (IIRC) +5 to +10 degrees or so.

Here's a very short video of a GPO master clock running, where I'd made up new suspension spring strips for the pendulum last year -

If it's any use...

Master clock running

If you've as much a half-a-thou to remove, I'd start with a second-cut or finer flat file, swept foreward and sideways across the area of bar you're seeking to reduce, hoping for a decent surface. If you see tramlines developing, stop and go over to strips of emery looped over the end of the file to provide a flat abrading surface. Finger pressure's enough to hold the strip and provides a bit of a safety feature - though I can't remember experiencing a snatch that was in any way dangerous over a lot of years. Keep speeds and pressure moderate. Choose a final emery grit that'll get you a suitable finish.

There can be much diversity of opinion over what you wrote, SOD.

There is a view that the defeat of the miners entailed the destruction of the mining industry and its huge engineering support base, which in turn undermined the machine tool industry. No effective plan was put in place, or even proposed AFAIK, to replace the local employment opportunities.

This left big post-industrial wastelands and an ageing skill base for manufacturing, the residue of which some of us on here represent. The bulk of the key productive resources we rely on are now either in foreign hands or dependent on foreign recruitment. How on earth we can pretend that Brexit has released us from such dependency I can't imagine. If we don't make our own clothespegs we shall have to pay others to do it, and ultimately pay for training their workforces to do so, and for their supporting industries to build the machinery. And if we don't do the basics, how can we hope to maintain the skills to do the jet engines, the vehicle batteries, controls and other hi-tech stuff?

We should be learning from our competitors; it's pointless and counterproductive to deliver false sneers at products whose capabilities are gin-clear to any objective observer.

If moderators regard this as political, I'm sorry - but 'twas a mod wot started it...

+1 for that. My Warco's been run regularly for 8 years now with no electrical issues.

Ketan's cautions are well worth bearing in mind too. Supposedly solid British machines, even those allegedly designed for an educational environment, aren't immune from a careless speed change. A local heritage railway's Colchester Student recently lost all 13 teeth off one end-pinion of a central headstock gear through such an incident. In searching 2nd hand replacement sources, it became very clear that practically every other gear in the headstock could be had in good condition from a breaker's, but the particular gear in question was only available new-manufactured at a price close to the market value of the whole lathe. Obviously this crash has been happening often, for long enough for someone to spot a market niche.

I've found on my Warco that the floor of the toolpost slot is 0.5" or 12,7mm below centre height within maybe a couple of thou or suchlike. So I buy 1/4" square secrion HSS toolblanks, grind the cutting geometry so as to take little or nothing off the top face at the cutting edge, and use a milled alli holder with a 0.250" thick base.

I only have to do a bit of shimming if I find I've taken too much off the top, and I've developed bench grinding technique to tthe point where that doesn't happen too often.

If the OP can use and obtain 10mm. square blanks, wouldn't it work to grind the top of the cutting edge to 9mm or the actual tool-slot-floor to CH dimension? Then shimming would only be needed to get you out of schtuck with a tool inadvertently ground too far down.

I have 3 of these, 1 for rough use, 1 for workshop, 1 spare if either of t'others should develop probs.:-

M&W calipers

I got from Machione-DRO but there are other dealers at decent prices.

I think they're a decent compromise, and they're adequate for most work.

Edited By Mick B1 on 26/04/2023 18:57:56

I thought there was quite a bit of adverse judgement in your initial post. It's OK to rant, but don't be surprised if others rant back.

Doh!

Thanks - yes, I should've thunk of that.

Nevertheless, as a turner who started in 1974, I don't believe I've ever actually seen a 4 jaw S/C, never mind used one, though I've known of them for I don't know how long.

I would expect one of those with a matching level of concentricity to be more expensive than a 3 law.

A good 3 jaw can hold work concentric within 0.0002 - 0.0005" :

Clocking the WM250V

Some horses can run better courses than they used to.

If a 4 jaw S/C can hold bare hex bar, I'd be interested to know how. If I wanted to do that with one, I'd expect to make a slit bush in brass, bored to the across corners size of the hex bar (generally measured rather than calculated, 'cos of the usual break edges), much as I do when I need to hold square material in the 3 jaw and prefer not to disturb it by swapping to 4 jaw independent. For most purposes, there's no significant concentricity issue.

Edited By Mick B1 on 22/04/2023 22:26:42

That's fair enough. The 3 jaw mayn't have the same grip, but it's horses for courses. I tend to find I need to use hex bar, both for models and railway work, plus I've never gone for records on cubic inches per minute metal removal. So the 3 jaw suits for me, with soft jaws to hold parts where there's not much to get hold of, and occasionally the 4-jaw independent for odd profiles and eccentrics. Hot-rolled black bar is something I've not seen in a while, though presumably it's still available.

I think it'd be quite unusual aluminium round bar work that the 3 jaw couldn't handle.

Edited By Mick B1 on 22/04/2023 19:23:36

The reason for the Myford procedure is that in the old days it was more difficult to achieve consistent low tolerances in chuck mountings than it is now.

Lathes for industrial as well as domestic/hobby use were typically sold initially without fitted tooling like chucks, even if such accessories formed other item lines on the same order.. So the idea was that buyers would mount the backplate on their threaded spindle nose and turn its O/D to a precision location fit in the counterbore of the chuck they happened to have, and drill clearance holes for the screws to secure the chuck body - which would therefore run to the best practically-achievable concentricity.

Engineers are required to spot this sort of thing, and to be ingenious (note liguistic-derivation pun) in their resolution of it.

Undoubtedly there's a culture associated with this, and part of it is due to the usually humiliating period of apprenticeship young people wanting to enter the field would have had to endure. Many are unwilling to give away for free the knowledge they've acquired at such personal cost - or perhaps, not so much unwilling, as that it simply doesn't occur to them to do so. Plus there's so much of this kind of background knowledge that most of us just don't know where to start in trying to shortcut someone to it.

Of course the world has moved on since then, and it's pretty easy now to buy a lathe already equipped with a basic selection of tooling - but for that you'd generally have to pay more, either buying new (probably from the Far East) or a running machine sold in good order as a going concern by somebody giving up.

Basically the facts of the game are *very generally* that if you want cheap, you need to have the knowledge and skills to provide the value you're avoiding paying money for.

Edited By Mick B1 on 21/04/2023 13:34:54

One of our local Tescos is closing its filling station for several weeks' refurb.

Me missus said, "Ah, they'll be putting in EV charging points".

"How'll they do that?" I said. "People usually do their shopping, then fuel up on the way out. Even the quick recharges for EVs take 30 minutes instead of 3, so they're gonna need at least 10 times the space and 10 times the number of points, aren't they?"

"They'll have to rebuild the caff bigger and nearer the filling station, too," she said.

It freaked me a bit at first on my Warco, but you can get used to anything. If I'm milling or co-ordinate drilling using the crossslide I double the metric offset I dial in. What complicates it more is that my vertical slide's a Myford Imperial.

I know I could buy a DRO set, but (a) I'm a cheapskate, (b) too lazy to want to go through the learning curve to fit and calibrate the things, and (c) believe in maintaining the mental calculation exercise.

I've had it 8 years and so far I've coped.

And more-or-less reduced the others in the squad to ammunition mules.

Found that someone had assembled the hinge pins I'd made into the smokebox door for one of the S160s.

Easily pleased, me.

I'd offered to put in a cross hole for a splitpin or suchlike, but nobody cared . Presumably gravity's adequate.