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Member postings for Simon Williams 3

Here is a list of all the postings Simon Williams 3 has made in our forums. Click on a thread name to jump to the thread.

Thread: Drilling then Tapping in Drill Press
04/12/2020 23:51:24

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

Thread: Myford Metric Conversion
04/12/2020 14:11:17

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Is it as simple as the 1480 kit suited the old Mk 1 gearbox, and the 1481/1 superseded it when the later (double speed) gearbox was marketed?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

dsc_0530-1.jpg

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

dsc_0531-1.jpg

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

Thread: COLCHESTER BANTAM PROBLEM
03/12/2020 19:32:45

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

But thank you for your concern.

Simon

03/12/2020 16:26:44

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.

03/12/2020 15:16:59

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

03/12/2020 12:24:24

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

Thread: "restoring" a Colchester student, anything to consider?
25/11/2020 20:08:45

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

Thread: Composite washers for Bullfinch and Sievert propane torches
15/11/2020 13:33:38

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

15/11/2020 00:21:09

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

Thread: Tom Senior LV modifications.
13/11/2020 16:36:15

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

Thread: Hand drilling stainless steel 3mm thick
09/11/2020 12:52:14

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

Thread: Bantam gearbox oil filling
05/11/2020 20:36:58

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

05/11/2020 19:25:16

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

Thread: bore measurement
31/10/2020 09:19:51

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

Thread: Tom Senior
26/10/2020 16:32:59

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

26/10/2020 12:23:11

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

Thread: De-magnetising
24/10/2020 19:27:51

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

Thread: Digital readings
22/10/2020 10:25:53

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

Thread: Fluxes for silver soldering.
09/10/2020 16:44:31

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.

Thread: Bleeding hydraulics
08/10/2020 13:50:36

+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.

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