Member postings for Simon Williams 3

Good afternoon and season's greetings all.

I've been looking for a definitive statement for the shaft size limits for standard taperlock bushes. I have a 3020 bush on a nominal 48 mm shaft which measures 48.01 mm and it seems awful tight to get on.

I want to fit a flywheel to the other end of this shaft, which would involve a 2012 bush, and 48 mm is at the very top of the range of sizes for a 2012 bush. This end of the shaft is presently 48.04 mm dia. Do I need to get nearer to the nominal 48 mm dia?

I've found a passing reference in the Fenner catalogue indicating that (quote) "accommodates shaft limits of +0.051/ - 0.127 mm". My shaft sizes fall inside these limits, but this gives no indication that the shaft tolerance might change with shaft size as I would have expected.

As ever, my thanks for the expertise.

Any ideas?

PS (edit)  It always helps to know the application.  I'm making a simple stone crusher, as I have a large pile of useless stone and several boggy gateways.  And I want to clear the stone but am too tight fisted to pay someone to haul it away.  So I thought the last lockdown would be usefully invested in making a gadget.  

I'll add a link to a Youtube video of its very first outing to a separate post,

Edited By Simon Williams 3 on 29/12/2020 16:51:32

Now there's an interesting little snippet I must scribble in the margin of my Zeus book.

I'd been warned by JS that some cutters (he said of Chinese origin) numbered "backwards". I hadn't twigged it's related to the module/DP swap-over.

Thanks for that pearl, and a Happy New Year to all.

Hedge your bets and carry a spare

The gear elements of the coupler seem to be pretty much sussed, so turning our attention to the flexy disc.....

I've made something similar by casting it from silicon RTV (silicon sealer). I made an aluminium mould to constrain the goo from going walkabout, and coated the surfaces with 3 - in - 1 oil to stop it sticking. Then just added RTV silicon from a squirty cartridge and let it set for a couple of days.

There is an expensive non-corrosive RTV option; I used the simple builders gloop which stinks of acetic acid as it sets. Once it's solid the acid isn't a problem.

Season's Greetings all

Simon

"May your God go with you". There's a concept with which to juggle.

And thank you to Neil, Jason, Dave and Mike, and the other essential elements of this wonderful meeting place. That's us, the contributors.

May 2021 be happy, healthy and wise. Why only May> (Don't call me Surely)

Simon

Good evening, I've played this game too, and I think you have several difficulties compounding the problem.

Firstly the disc you bought had a tag in it on the periphery. This tells us it's likely the offcut from cutting a hole - so that's why it's cheap. Cheap it may have been, but you would have been much happier with a clean disc,

The plasma cutting action of itself (assuming it's just mild steel) won't harden the disc. That's not the problem, the issue is that the oxide layer (and the snotty grotty bits) left on the outside is (b$$$$y) awful stuff, and your poor little lathe did well to tackle it. Buying a blank which is clean cut on the outside will make your life infinitely easier.

That said, cleaning up the oxide layer with an HSS tool is a recipe for going nowhere. You need a carbide cutting edge of some kind, and inserted tools are good but there ain't no substitute for horsepower. Sorry, but that's cold comfort in your case. For some reason brazed tools are often better at the brutal business of getting back to clean metal, it's all in the composition of the carbide edge. That is as much as anything about the cost per edge of an inserted cutter against the re-sharpenability of a brazed cutter.

You can do an awful lot to make it easier by tackling the periphery with a grinder of some description - a bench grinder is good, an angle grinder with a linishing disc (sanding disc - but coarse and aggressive and a hard abrasive) - is better if only because it saves ruining the shape of the grinding wheel. A belt sander will do a good job.

Essentially the moral of the story is - as ever - you gets what you pays for. If you can find a supplier who DOESN'T stick you with a in-cut on the edge (where the plasma pierced the sheet metal before setting off on the circular path) you will get on better, a few minutes work with some sort of grinder will save you a whole bag of grief, and then get in there with a tool which won't burn out (even HSS will) if you approach the edge at a ridiculously high surface speed. If I buy a cut blank I expect it to be clean edges and would get very chopsy if it had a cut in the edge I had to machine away.

Good luck,

All the best Simon

Blow a hole with the arc welder (plasma would be even better). Grind off the snots with an angle grinder - linishing disc.

Tidy the hole (if it needs it) with a Dremel or a die grinder. They sell little cylindrical stones for sharpening chainsaws which are just the very thing.

Enjoy!

A common, and annoying, situation.

Several ideas for work-rounds.

Ditch the tap guide, clamp the tap in the drill chuck and turn that. The chuck key make a nice tommy bar.

Ditch the tap guide, clamp the tap in the drill chuck and tap under power. (Not without its perils!!!!!)

Ditch the tap guide, don't clamp the tap in the chuck, just hold it loosely so it is held upright. Grind a square on the shank of the tap and fit your tap wrench to the middle of the tap not the usual square on the top end. You need three hands or a quill lock to make this work!

If your drill press has a morse taper, ditch the drill chuck, and hold the tap guide in a morse taper collet held in the spindle. This needs the quill of the spindle to be drilled lengthways as per a vertical milling machine so you can close the collet.

For a drill press without a hollow spindle, make a tap guide on a morse taper. As far as I know there isn't such a thing available commercially, but it's a nice little project.

Attacking the problem from the other end, so to speak, invest in the requisite sizes of long drills so as to make the set-up for drilling the holes equivalent length to the later tap plus guide set-up.

Buy a vertical mill with a dovetail column. This isn't quite as radical as it sounds, it's an entirely logical progression in developing the capability of your workshop. No my wife didn't accept this logic either.

I expect there are other ideas will be along shortly.

Bst rgds Simon

Brian - good afternoon.

Is it as simple as the 1480 kit suited the old Mk 1 gearbox, and the 1481/1 superseded it when the later (double speed) gearbox was marketed? Or is that too simplistic?

I'm trying to think if I've got enough information to follow this through and check the arithmetic works out right.

I believe that this is the diagram for the 1481 kit:

And the label issued for the 1481/1 kit looked like this:

I'm fairly sure (but haven't dusted off my notes from the last time we visited this) that the newer kit needed one less changewheel to achieve the same result. Which could, of course, have been the reason Myford decided to update the kit.

Best regards Simon

If that's aimed at me, there isn't.

But thank you for your concern.

Simon

Sounds like that's a plan!

I've got a Bantam 2000, which is the same thing as an 800 but originally with a two speed motor and slightly different gearing (drive pulleys?).

One of the functions of the original switch is to stop you energising the controls after power on if the apron switch is not in the "stopped" position. So the motor can't do an involuntary start if the mains fails and returns (no volt release function).

I use this as part of the E stop function via the foot switch, so that once you have pressed the foot switch you have to move the apron switch to OFF before the controls will re-energise. It means that the foot brake is an emergency stop, which is not ideal if threading up to a shoulder for example, but I thought it was a price worth paying.

I re-built mine to use a VFD whilst keeping the original switches so it looks and functions as closely as possible to the original. The reversing function uses the switch contacts of this F/O/R switch connected directly into the VFD , no longer taking the motor current.

Rgds to all

Simon

The two speed function is now achieved by feeding a single speed motor with 50 or 100 Hz. Actually this won't get me the top 2000 rpm speed as the motor runs out of puff, but otherwise it's been very successful.

I had a look in the Kraus and Naimer catalogue, they certainly do similar things. You might need to get your local K & N rep to take an interest!

Copy of the Kraus and Naimer C and CA switch catalogue here

There seem to be options for the operating angle, including 30 deg. I didn't find the precise electrical functionality, but it's only a combination of stuff they do in other switches. I've even (in desperation) mixed and matched the internals 'cos I was a long way from home and it was my ticket to paradise, but it's a pig of a job.

Let us know how it goes.

Rgds Simon

My copy of the parts list shows a part number of the F/O/R switch but doesn't show a picture. It's a long time since I had the switchgear in pieces, and I can't readily get to it, so could you post a picture of the offending item? Does it have a manufacturer and a part number on it? The operating mechanism is a bit special, but the body of the switch if I remember right is a standard item.

From the cct diagram it's drawn as a six pole cam switch with four changeover poles (i.e. two as on/off/off and two as off/off/on) , the third (correction - fifth)  pole is on-off-on, and the fourth (correction - sixth) pole is off/on/off so it's nothing special. If you take the original to your local electrical wholesaler - City Electrical or Newey and Eyre or similar - they should be able to identify something functionally equivalent.

HTH Simon

Edit - corrected the pole numbers, I originally mis-counted the number of poles as four not six.

Edited By Simon Williams 3 on 03/12/2020 12:45:56

Grabbit!

OK so it's a gamble on the time and effort and cost of collecting it, but if it is a dog it's still worth the money. Doesn't seem much of a risk to me.

Be careful loading it and transporting it. Most of its 700 Kg is in the headstock and bed, the stand isn't (comparatively) very heavy. So the centre of gravy is at least a metre off the floor , so it's top heavy as fun. Go to ridiculous lengths to not let it tilt AT ALL.

Good luck, happy Studenting.

Rgds Simon

I'm with Keith.

Could Andrew put a photo of the bits up for us, we must be talking at cross purposes here.

Rgds Simon

I've not played with Bullfinch stuff much, but I'm an expert in burning my hand on the Sievert nozzle.

So I can assure you that the nozzle gets hot. Very hot. Oxide dis-colouring hot.

Upon which basis I doubt that a rubber washer is going to cut the mustard (hot or otherwise).

I've also had experience (albeit not to an expert level) on having the nozzle come loose on the neck, and the whole thing breaking out in a ball of flame. Which is exciting but not useful. That's why I grabbed the nozzle to tighten it, and regretted it shortly afterwards and for some time thereafter.

My impression is that the Sievert washers are lead or possibly some kind of graphite material.

Seven quid a pair? Bargain of the week!

Stay safe (or is it too late?)

Simon

edited for minor typo

Edited By Simon Williams 3 on 15/11/2020 00:22:48

Excuse me for butting in chaps, but.....

So long as the gib lock isn't engaged, If the weight of the knee isn't sufficient to overcome the friction of the gibs, in the Z axis, then the gibs are adjusted wrongly.

Given the weight of the knee is always in contact with the upper face of the Z axis leadscrew, there is no backlash.

There is still a modicum of backlash in the bevel gears conrolling the leadscrew; one would hope this was insignificant.

Rgds Simon

Yes, as Mechman says you've got into the work hardening problem, where the tip of the drill skates on the surface of the hole and no amount of rotation will progress the drill forward. Pressure is your friend, by which I mean drilling a smaller hole. But then the drill is (disproportionately) more fragile. If it cuts through the hardened area (which is a big if) it's likely to snatch and break, and that's if you can avoid putting side forces on the drill, which will also break it.

Having drilled a pilot hole it's not guaranteed you can drill it out to size, that material is going to grab the drill and snatch again, always supposing you can get under the hard skin.

Cutting oil or coolant would have helped, but are now irrelevant. You needed pressure on the cutting edge to keep it cutting. Once it skates you're lost.

I wonder if you would be better off going abrasive. Having got the hole area work hardened I'd rather have a go with a carbide bur in a Dremel kind of tool. Keep the area wet to keep the tool from burning out, but you should be able to make progress, if slowly. Once you've got a hole open it out - if need be with a stone point (they sell grinding burs for sharpening chainsaws - they have all sorts of other uses).

Carbide drills or carbide tipped drills both need lots of pressure, so you're fighting the inevitable trying to use them in a hand drill. And, as you say they are very brittle so sideways pressure will shatter them.

Good luck

Simon

You've got me going now. But the manual does have oil fill capacities, they just hid 'em. Page 18/19 of the User Manual says the headstock takes 6 pints, the gearbox takes 1 pint. Suggests Shell Tellus 27, but that's just a general purpose thinnish hydraulic oil. I use 30 grade in a hydraulic hedge trimmer, I'm sure that'll do the job.

Rgds Simon

Take off the fibreglass gear cover (LHS of lathe).

There is a knurled plug about 25 mm dia on top of the curved surface of the cast cover LHS of the gearbox. It's got a breather hole in the centre. Its just in front of the 100/120 gear cluster.

Unscrew it and there is a 20 mm or thereabouts filler hole below.

HTH Simon

edit If you have a copy of the manual, it's the lower picture on page 6 of the parts book, If you need a copy I can't do it now the wife is on the scanner, but I'll add a picture later

Edited By Simon Williams 3 on 05/11/2020 19:29:16