Member postings for Glyn Davies

I have a VMC with R8 taper and share your frustration. Havent got around to it yet, but I wonder about adding a collar to the drawbar between the top of the R8 collet and the inside of the spindle so that unscrewing the drawbar self ejects the collet. Then making a hole in the belt cover to allow the drawbar to be screwed and unscrewed using a cordless drill with a socket.

In the meantime, I've removed the R8 alignment pin from the spindle, which at least saves a few seconds each time I change the tooling.

My VMC knocked quite badly when I first got it. Traced the problem to the motor pulley. I slackened both pulley grub screws and then tightened the one opposite the key as tight as I could, then tightened the key side screw just snugly. Cured the knock.

Thanks for the replies - Dave's was particularly useful in improving my limited it knowledge!

I tried switching off the router for a few minutes and, on turning it back on could then access lathes.uk, albeit with a not secure warning in the header. Will monitor and report further incidents if they occur.

Edited By Glyn Davies on 17/03/2023 18:56:36

Just tried to access lathes.uk using the phone - using WiFi I get the 400 error; turn off WiFi and use 4g and no problem. So it's my talk talk isp?

For some reason, many of the websites in my favourites have recently started to generate a 400 series error when I try and access them. Lathes.uk being an example. Also get asked for a username and password on some sites as the site is not secure. The internet says the standard fix for this is to clear the computer cookie cache, which I've done but it makes no difference.

My PC never used to do this, so has a Windows update caused it? It's very frustrating and I get the same result when I try and access the troublesome sites on my phone.

Any suggestions?

I mounted a cheap 3 jaw chuck to an angle plate and leave it permanently set up on my D-W miller. No DRO, so I turn a piece of scrap 1/4" rod to form a pip whose diameter equals the thickness of the slitting saw. Then align by eye. If using small countersunk Allen screws, I slot them to allow them to be removed if the hex socket becomes rounded.

Thanks for the additional replies - I've learned a lot! In the short term, I've ordered some SR160 diodes to replace the BAT41s and as a longer term fix, have ordered from China the multipurpose charger circuit. When I get that, I'll connect a battery to the output and see if there's any voltage at the input. If there's none I can presumably ditch the blocking diodes altogether.

For interest, here's the lamp as first built running on propane:

And here's the LED conversion:

Thanks for the replies. I had some LEDs and diodes spare so I used my power supply to test the actual resistance of the diode. With the voltage set to 5V (the max open circuit voltage of the solar cells), with no diode, the current is 67mA; with a diode in circuit, the voltage across the LED is 4.4V and the current is 45mA. With the voltage set at 3.6V and no diode, the current is 31mA. With a diode, the voltage across the LED is 3.0V and the current is 9mA. So by my reckoning, the diode resistance is .6/.045 = 13 ohm at 5V and .6/.009 = 66 ohm at 3.6V. I tried two diodes in parallel and the voltage and current were the same as with one diode.
I have no data sheet for the solar cells (off ebay) - is there a way of finding if there is a blocking diode in them without causing damage? The cells are 100mm x 172mm and are rated at 2W at 5V. I measured the 270K by putting my pocket multimeter across a diode.

I have been asked to convert a propane eternal flame to solar powered LED. This is the set up I have built and it seems to be working well, with the batteries powering the LED as daylight fades.My question concerns the diodes. I just measured the forward resistance of a BAT41 diode at 270K ohms. I thought diodes were low resistance in the forward direction. Would the set up work better if I replaced a single diode with two or more diodes in parallel? Are there any other improvements that could be made to the circuit? My electronics knowledge is limited! Thanks.

Lidl is currently selling 6" bench grinders for £21. These have a 200W 2980rpm induction (I think) motor, which is a bit weak for 6" grinding wheels, but I bought one with a view to re-purposing it. I removed the motor end caps and extracted the spindle and cut off both ends. I then turned the right hand end to 12mm and cut an M8 thread to take an angle grinding adapter.

The result is shown in the photos and allows accessories such as sanding discs or the thin cut off wheels to be mounted. These latter are useful for roughing out HSS lathe tools to be used for parting or screwcutting.

I extended the tool rest by drilling a couple of 3/16 holes in the original and clamping a piece of 2" x 1 1/2" x 1/16" plate to it. I then filled the holes using a stick welder, sticking the extension plate to the original rest.

I think the motor is a gem for the money - very quiet and smooth running and enough power to drive angle grinder tooling.

I found these gauge ball sets for sale:

They come in metric or imperial and contain pairs of balls up to 1" or 25mm diameter. Can anyone tell me what they are used for in industry? All I can think of is measuring internal cone angles or measuring dovetails.

Thanks

Thanks Michael, I'll give it a go.

I just bought a nice compact 12X monocular off eBay. It cost £10 and offers quite good imagery but the body is plastic. I'm curious to know if the lenses are glass or plastic. Is there any way to tell, other than trying to scratch them? Thanks.

I don't have a 127 tooth gear, but looking at my gearing spreadsheet and using the metric conversion set, with:

Tumbler stud - 30t

Gearbox input gear (gear X) - 127t

First stud driven - 60t

First stud driver - 80t

Gives exactly:

A1 - 1mm pitch

B1 - 0.5mm pitch

C1 - 0.25mm pitch

A4 - 0.8mm pitch

B4 - 0.4mm pitch

C4 - 0.2mm pitch.

The arrangement looks like it will fit the standard metric conversion banjo.

The standard metric conversion set using the 63t gear gives an error of .00125mm per 10mm of thread length in all the metric pitches.

On my 2017 VMC, this is the speed sticker on the belt guard:

This is the pulley arrangement:

This is the speed table I constructed having measured each speed with a tacho:

I have reamed Delrin with a mild steel D bit reamer and it cut to size. I turned the reamer to size and put about a 1mm chamfer on the front end before milling it to a D form. I'd obviously ream the bore before turning the OD.

If I understand the task here, it's to produce some flat area in the chamber that is a defined distance from the top face of the cylinder head so as to provide a guide when using a mounted point on a flexible shaft grinder to fully profile the chamber. Why not set the depth on your pillar drill and use a small diameter end mill (~5mm) to create a number of spot faces in each chamber? Or just use a 5mm drill instead of the end mill.

If the valve seats are already cut, you could make a pair of dummy valves that protect the seats and sit in the seat at the correct depth to act as a further guide when grinding.

I still have my 1973 Vizard's guide to cylinder head modification from my 998cc Mini days and scanned the 1275 Midget template:

Edited By Glyn Davies on 01/07/2021 10:46:59

Here are pics of the No1:

I set up an experiment some time ago with my Aldi calliper where I powered it from an external 1.5v source so I could measure the current drawn. I forget the value of current (very small) but it was exactly the same whether the display was on or off.

Found this old card, could be your man: