Member postings for Simon Williams 3

OP doesn't identify the make or quality of the telescopic gauges.

With good quality (M&W, Starrett, Mitutoyo) gauges and practice you can get sub 'thou repeatability, then measuring this with an external micrometer introduces its own error. Overall repeatability with practice and developing a feel for the technique, expect to get repeatability of measurement say +/- 1 thou.

Cheap and clonky telescopic gauges won't let you develop the "feel" successfully.

There is a definite knack to setting the gauge in the bore - refer to Adam Booth's technique on Youtube. But you do need to practice.

edit - Emgee and Tony type quicker'n me.

Edited By Simon Williams 3 on 31/10/2020 09:21:06

Old Mart and Clive - thank you for pointing out my over-simplification. You are indeed right to point out that the top is top (edit - I meant too heavy, but the typo is appropriate!) heavy for a one man lift at that height and reach. . My defense is that I thought it self-evident not to undo both clamps together. Even that's not as simple to do as say - if the clamps aren't holding!

I like the idea of sticking something suitable in the taper and restraining the other end laterally!

My contribution is to caution against trying to withdraw the top bar out of the two clamps without having the clamp bolts in position, and just snugged up to stop the split clamp opening. It would be all too easy to allow the overhanging weight etc to crowbar the nearer clamp open as you bring the bar etc. forward out of the rear clamp. Ping!

I'm looking forward to hearing how this pans out.

Rgds to all our Senior citizens.

Simon

edit for typo

Edited By Simon Williams 3 on 26/10/2020 16:35:15

If Dave's sleuthing instincts are true to form, and it is the TS Light Vertical, failure to clamp that top bar only has a couple of explanations.

- Studs or casting are damaged, so the clamp nuts are not closing the split clamp.

- Summat in the split gap stopping it closing

Adding shim etc isn't tackling the problem, its creating another.

So remove the two studs (1/2 whit) and pass a feeler gauge through the split to check for clearance. While checking make sure the clamps haven't cracked through the heel, they're only cast iron. Check the nuts on their respective studs that they run freely.

Clean the bar off so it is free of surface rust and grubbage.

The clamps on mine are a very close fit on the bar, the clamp nuts only need nipping up lightly to stop any movement of the head.

Do let us know how it resolves

Rgds Simon

Somebody correct me if I'm wrong, but isn't the magnetic field in the centre of a toroid identically zero? The lines of flux are toroidal to connect the windings magnetically, it's only leakage flux remnant at the centre?

Rgds to all Simon

I'm with Maurice on this one, though I don't understand why. It can't be just that the width of the space between successive lines on the barrel is narrower - though it is - that's only 5 thou difference. But it is perfectly true that |I find reading a good metric mic' much more difficult than an imperial one. I find myself checking the mic' with digital calipers to see if I read the mic' right!

I even went so far as to modify my little Starrett metric mic' - Micrometer Blues - which has improved it but I still don't find it as intuitive as it should be.

I put it down to old age and dodgy eyesight. If so why is the imperial mic' not equally blurred?

Rgds Simon

Horses and courses again.

Borax (if I remember right) only works at red heat, using it in conjunction with low temp' silver solders doesn't work well. Good for gold soldering. OK on soldering Sterling silver, but bog standard yellow silver solder doesn't get hot enough to enter the range where borax is active.

EasyFlow Flux is suitable for low temperature (dull red heat) solders, easy to clean but exhausts quickly, and is intolerant of dirt. Tenacity solves some of these problems but is a devil to clean up. Tenacity will wet stainless steel (and some carbides), EasyFlow won't.

More complication comes when working with stuff for hall marking, and where the sequence of assembly means subsequent soldering operations, possibly at (slightly|) reducing temperatures. Easyflow won't survive being heated twice, Tenacity will.

For different grades of Tenacity, I'll defer to the maker's blurb.

+1 for NDIY's advice. Even if there is a trapped air pocket in a dead end, the amount of fluid and the velocities with which it travels will carry any air away readily. It's good advice to sweep the stroke of a newly installed cylinder a few times to exchange the oil and pass the oil with entrained (or even dissolved) air back to the reservoir tank. But normal operation will clear any remnant air in the fullness of time anyway.

Also bear in mind that even if the actuator cylinder is full of air, introducing fluid at pressure will pressurise it anyway, and effectively there is no limit to the amount of liquid available. Thus the hydraulic system will reach enough pressure to overcome the load (within the normal working constraints of allowable applied pressure) even if there is trapped air in the system. It just means that more oil will be needed to achieve working pressure that would be the case if there was no air in the system. The hydraulics operate, but may behave oddly.

Nothing could be further from the truth with conventional mechanical hydraulic brakes, where the available volume of fluid is that of of the (part) stroke of the master cylinder. In consequence of the limited fluid displacement there is a very limited (if any) exchange of fluid each operation, so any air included is not swept back to tank where it can be rejected by the fluid.

I did some experiments once upon a time with the behaviour of air in brake fluid. Actually it dissolves into the fluid quite readily at pressures of typically 2 - 3000 psi, but then comes straight back out of solution when the pressure is released.

This has cropped up before, and I seem to remember there is something odd about the tumbler gear operation on the Southbend.

But I'll ask the question anyway - if you move the tumbler gear to reverse the leadscrew does that not lose the registration between the leadscrew and the spindle? 'Cos if so you just screwed (pun intended) up your thread!

To rhyme with "bostin",....

Reference the comments above about "why use a diamond".

You can indeed use a carbide tip, or even another abrasive to dress the wheel, but it's horses for courses. I use a coarse carborundum stick for roughing the wheel but it leaves a crushed grit surface with a limited abrasiveness - it blunts the wheel grains and therefore the wheel loses some of its free-cutting properties. A wheel surface which is blunted in this way will cut as if it were a finer grit, but will generate more heat as the grains rub rather than cut. A carbide tip will have the same blunting effect as it crushes the grains it touches exposed on the periphery of the wheel.

Different wheel materials give different results - I have a white wheel I use for sharpening twist drills etc (HSS) and this is less susceptible to the "crushed grains" effect. Understanding the different effects of this means getting into the intricacies of the wheel construction - a green grit wheel for example is a hard grit in a relatively soft bond so the grit is renewed quickly as it cuts. A grey wheel is a soft(ish) grit in a hard bond so it survives the rigours of daily sharpening HSS with occasional (whisper it quietly) contact with bits of mild steel.

A diamond cuts the grains, and as a result leaves a much more free cutting wheel surface. It will cut more freely and cooler, and behave as a wheel of the designated grit.

If you want a really free cutting wheel - particularly if it is a fairly coarse grit wheel for coarse material shaping - then the old fashioned star wheel dresser is the thing. This pulls grit particles out of the surface of the wheel, creating a horrendous abrasive dust hazard, but the advantage is that the wheel will cut with a vengeance.

Hi everyone, and welcome to our new moderators.

I've been reviewing my inbox tonight, and I notice that the sender's name is mostly in blue, underlined. If I hover over it the little hand appears, so it is a hyperlink.

I also have one message from a member whose name appears in black. It also provides the little hand and the hyperlink.

What is the significance of black against blue please?

So has this cured the problem, or are you still suffering the same difficulty after fitting a new blade? Or perhaps (perish the thought) things were going just fine until you changed the blade??

Either way, check the blade isn't riding on the step flange on the wheels. It should be running adjacent to the step in the wheels' flange, but not on it. But you'd knno if it were, it puts a shoulder down the length of the blade.

Now why do I know that?,

+ 1 from me for change the blade.

What seems to happen is the set gets lop sided on the teeth, and/or unsymmetrically blunt, and the blade won't cut straight for love nor money. There is nothing you can do to keep the blade on the drive wheels|!

I've gone over to HSS blades, they're expensive but they're worth it.

HTH Simon

"Reasonable"?

Huh! I'd be mighty chuffed if I'd measured that.

For "reasonable" read "pretty blooming excellent!

Rgds Simon

PS But (if I remember right) that wasn't Hopper's concern.  To make a flat face at right angles to the axis of rotation you need the saddle to move at right angles to the face plate.  So this is checked by passing the dial indicator across the face plate surface, rather that rotating the face plate wit the DTI stationary.

Correct me if I'm wrong anyone?

Edit - PS added to treat Premature Send Button Syndrome

Edited By Simon Williams 3 on 15/08/2020 00:34:24

Ah ha!

We seem to have established this is a single speed drive, so the top speed is likely to be 800 rpm. It would be useful to know (by measurement in real life) what the top achievable speed is, also what does the gearbox plate say it is?

I have a 1.1 Kw motor on a Bantam 2000, my experience is that the top gear/high speed is beyond the capabilities of this motor. Otherwise it's brilliant, run off a Telemecanique/Schneider ATV inverter converting single phase to three on a simple 13amp plug.

On that basis I'd expect a 1 HP motor to drive the (low?) top speed perfectly well. BUT it's got to be configured in delta for a 230 volt line to line out of a simple inverter. The soft start function (if it's available) is an advantage.

As for the motor being weedy, give it some work and see if it struggles. More power isn't necessarily "a good thing" , it depends on whether you can turn (pun intended) it into useful work.

HTH Simon

Good morning Tom, welcome to the madhouse. From the sounds of it you have yourself a very pretty Mk2 Bantam, comes in various guises, the two speed ones are either 1600 RPM version or a 2000 rpm version.

The original motor is wound as a 4 pole or a 2 pole machine, and the connections to it go via a multipole four position switch (high/off/low/off) located under the front of the chip tray, The original motor will have been taken off because the windings need 400 volts and the conversion to run in delta on 230 volts is too complicated.

Unfortunately the 2 speed motor I took off mine got scrapped in the last factory move, but I'd stick with the inverter for sure. High and low speeds - particularly the ability to go below the marked bottom speed on a large diameter item - soft start, dynamic braking and all the other advantages of a VFD. Assuming, as above, that the inverter has these functions. If not I would spend the money on fitting one that does, not resurrecting the original controls.

Power limit with a geared head machine is unlikely to be a deciding factor in a hobby shop, and if it is I suggest a Bantam isn't the right tool for the job.

If you do want to return the electrics to original all the details are in the user manual, copies often on ebay or from Tony at lathes.co.uk. There are circuit diagrams for all the variants.

HTH Simon

If you google IEC 60309 the colour of the cable relates to the convention of relating working voltage to the socket cover colour for multi-pin outdoor connectors. Formerly BS4343.

I don't know if there is a formalised connection to the colour of the cable sheath, but having worked extensively on construction sites in the UK I know I'd be thrown off site for presenting extension cables not compliant with the colour convention a la IEC 60309.

We also encountered 24 V AC cable and connectors in a pretty lavender colour.

Rgds Simon

Back in the days when iron was shaped with a hammer and chisel, one of the tools in the blacksmith's grubby hand would have been a square chisel, used to cut grooves across the face of the work piece before using a flat chisel to take off the lands. One such of an appropriate cross section with the end ground flat instead of oblique would serve.

Where would one buy such a thing? I guess one would make it, possibly starting with a suitably sized square file. Grind off the teeth, don't worry about over-heating it as you go, it's going to be heat treated later anyway.

Once it is to size and reasonable surface finish, stick it in the fire overnight to soften it, then heat treat it to blue as spring steel.

Robert is your father's next of kin.

Rgds Simon

I too live in a mobile phone desert. 5G?!........2G would be nice!

Some banks (NatWest is one) use a SMS to a mobile as a second confirmation. That just doesn't work for me. It means I have to go and lurk in a car park in the nearest town and use my 3G phone as both hotspot and to receive the SMS. I'm sure the spotty 17 year olds who dream up these nonsenses haven't understood how limited mobile phone network coverage is outside the urban jungle. Perhaps they don't think our business is worth worrying about.

I've changed my day to day banking to Lloyds, who use a better system which works over a land line by voice messaging, and stays away from SMS complelely. In my rural backwater this works quite well.

Is Paypal heading towards the stupidity of NatWest?

A very long time ago I joined the Instrument Mechanics Dept of what became Severn Trent Water, was then the North West Gloucestershire Water board, based at Staverton Airport between Cheltenham and Gloucester

Two of the chaps whose unfortunate lot was to look after me and make sure i didn't get into trouble recounted how they had been employed in a Clean Room environment, I don't remember for whom.

Their angle on this story was that Rizla papers were the only thing they had found which did not shed fibres, yet would absorb liquid. Hence they could be used in a clean room without contaminating the dust free atmosphere.

Best rgds Simon