Member postings for Peter Cook 6

That would work for width, but then I would loose the 10 inch thickness of the brick pillars in the overall length, and with a 2020 SUV and a 1970's integral garage I only have about four inches spare in length. The only real answer is a smaller car!!

Edited By Peter Cook 6 on 18/09/2022 10:39:34

C'mon guys and gals. This is an engineering forum. Surely the answer is a pair of good quality fine knurling wheels and a little ingenuity!

One thing to watch - assuming you are going to put a car in the garage - is the width of the mechanism at the side. I have considered replacing my old up and overs with rollers, but the side mechanisms takes more space than I can afford if I still want to get the car in.

I'm with Dave. Like him I had a test as part of a panel of tests to investigate a different problem. I was asymptomatic for prostate problems, but the test came back at 62! Cue panic at the doctors - them not me - and an appointment with oncology for five days later. For a diagnosis of T3. Five years down the road, After 4 years of hormone therapy wrapped around 35 trips on the radiotherapy machine my PSA is 0.09, I still have a prostate & no symptoms.

typo

Edited By Peter Cook 6 on 16/09/2022 21:04:07

I use a Taig which is the same size as the Sherline. I took Jason's advice a few years ago and opted for APT's CCGT 060202 inserts in a set of ARC's SCLC 6mm x 6mm holders. On my little lathe they cut brilliantly for anything ( alu, brass or steel) that I turn. The holders need very little shimming in the standard Taig toolposts and the tips will take very fine cuts if needed.

Edited By Peter Cook 6 on 15/09/2022 11:48:20

I think the trepanning process (step 4) is going to be difficult - especially in stainless and gripped on a 25mm hole in the internal Jaws. It's also not going to help with the final precision of the 25mm bore. I would

1) Make a short arbour from bar you have available. Put a flat on it.

2) Mark the centre of the bar and drill the hole to suit the arbour.

3) Drill & tap from one of the 75mm sides for the grubscrew

4) Rough out the circle with a bandsaw (or hacksaw!)

5) Mount the rough circle on the arbour using the grubscrew and turn the outside to 75mm

5) Remove the arbour, mount the disk in the chuck (3 or 4 jaw depending on the precision of centrality you need)

6) Face.

7) Flip and face then bore central hole to size.

Edited By Peter Cook 6 on 10/09/2022 20:41:34

Could you add a fixture plate on top of the existing bed if the damage is too extensive to live with. Depending on the size, a plate might be cheaper than having the existing bed machined.

Waitrose have done the same thing. The label colour on the bottle does however still follow the colour convention

My SX1LP mill uses MT2 taper. With myER16 adapter I simply take the nut off, slip a piece of tube over the threads so that it meets on the bottom of the quill, then put an old ER16 nut on the threads and tighten. Pops the adapter out easy.

Try running the motor directly on 230v AC without the controller in the way. It will run at full speed, if it still runs noisily, you have a motor problem. If on the other hand it runs at full speed fairly quietly, then the noise you are getting is an artefact of the waveform generated by the PSU.

If its the latter I would at least try a simple low pass filter. Put a series resistor ( 5w 50ohms which will limit current inrush to about 5A) in the positive line and then a 500v 100µF capacitor across the +/- lines. That should supress frequencies above about 40Hz and give you a smoother DC supply.

Duncan, it would if you used a simple capacitor, but a smoothing circuit consists of a series choke (inductor) or resistor followed by the capacitor. The inrush to the capacitor caused by voltage spikes (or on start-up) is "dropped" across the inductor/resistor and if appropriately sized should give no problems.

Dave - I would agree that it should be unnecessary, but he was asking how to "clean" the DC.

Looking at the controller he has I suspect it is one of the cheap brush motor speed controllers available for <£10. They are not true PWM controllers (which usually run at high frequencies) but simply half wave rectify the incoming mains then chop each cycle short to give output voltage control. I have one I use to speed control an old Black & Decker drill . It works fine but has "ringing" spikes in the output on each half wave that cause a significant hum. I assume that is what he is trying to clean up.

Typo

Edited By Peter Cook 6 on 29/08/2022 15:31:54

I am assuming that is a universal brushed motor, as it's marked for mains AC power, but you say you are running it on DC.

Why not as a first (cheap) step simply smooth the DC output of your existing power supply. If you repair tube radio's you probably have a suitable choke and some reasonably big electrolytic capacitors with an appropriate voltage rating in your bits box.

All the commercial circuits will be the same basic design as the one you have - the cost just reflects the level of smoothing applied to the output. Making one yourself will almost certainly cost more for the components than you can buy a ready made one for.

Reverse the motor?

Nope, just hoping that you don't associate the new name with the old awful reputation, so they can bury the bad image. Until this brand gets the same reputation.

Rebranding is probably cheaper and easier than fixing the underlying issues and then waiting until the improved reputation works through. Look how long it took for Skoda's reputation to recover.

Edited By Peter Cook 6 on 17/08/2022 13:20:54

Short length of tube which bears on the face of the quill, the other end of which bears on the back face of the collet nut. Tighten the nut while holding the spindle to squeeze the tube up onto the quill - pulls the taper down.

If the OD of the collet thread is bigger than the OD of the quill, slip the/a spanner in between the tube and the quill to provide a bearing surface.

Doesn't the Sherline High speed system have two concentric pulleys, so swapping from 10,000 max down to the other (2200 it seems to be) is just a question of shifting the belt on the pulley set rather than changing pulleys.

Trevor, perhaps now is the time to grab one of the free CAD packages, or a 90day trial of one of the paid for, and have a go.

Looking at the picture in post 7, the curve at the bottom looks very close to a semicircle. So either the board is 300mm wide and the slot in your drawing (post 4) should be 300mm long - in which case the simple print idea is not going to work, or the curve is 150mm diameter.

If it is 300mm wide, you could still print the difficult bits - make 2 of these

and bolt one at each end of a length of aluminium or steel bar 

Replies go there before I finished.

Edited By Peter Cook 6 on 09/08/2022 15:37:53

Edited By Peter Cook 6 on 09/08/2022 15:40:11

As it's only a check guage could you not 3D print it. My Ender 3 will print up to 220x220mm, so would accommodate the jig. Tolerance is pretty good <0.5mm so it would likely be accurate enough.

If it was OK you could knock off a few in case of accidents - they would come out a lot cheaper than Ali.

Something like

Cura says 128g of filament  so about £3 worth but 22 Hours printing time, however you can leave it to it.

Edited to add picture

Edited By Peter Cook 6 on 09/08/2022 14:07:46

Fine wire, pushed through the cord (a needle to make the initial hole) should be smaller than the cord.

A final input if anyone stumbles over this thread when planning to build one.

I cased the electronics for mine in a nice ABS box, and used it for the first time in anger the other day. It worked like a charm. Taking multiple cuts to mill curved slots in brass was soooo simple.

However It all got fiendishly hot. The motor got fairly warm, but no-one has mentioned how hot the stepper controller can get - especially in a closed box. The two bolts holding the stepper driver to the side of the box got so hot I almost burned my fingers.

This was my first experience of a stepper motor - the brushless motor on the lathe has a controller with exactly the same chassis and heat sink - but it never gets beyond vaguely warm. I suppose I should have realised. 12v in and only about 2V out with 2.8 amps holding current says that the driver is dissipating about 28 watts

Fortunately there was enough room in the box for a 40mm 12v fan ( the system runs on 12v) from the bits box, so some hole making and fettling provided a cooling flow. Things are much better now!

But now I know - stepper drivers get hot!