Member postings for old mart

If I had a cylinder square, I would expect it to be within 0.0001" in 8" of height on the diameter, and have a perfect finish, something I could not achieve by turning.

If you were designing a lathe chuck mounting for a small to medium lathe, the screw thread takes a lot of beating. At the design stage, a positive spindle lock and a locking device for running safely in reverse would not be difficult to include. My second choice would be a variation of the bolt on flange which the mini lathes have, but with more room between the headstock and the rear of the spindle flange. The type with the keyholes in a loose plate has a lot going for it in terms of easy chuck changing.

I think the camlock system is more suitable for larger machines.

Edited By old mart on 08/11/2019 16:50:08

Dead right, Mick, machine builders have to supply their products with safety devices to satisfy the legislation, but there is nothing that says that the design has to be actually usable. Some of the worst designs are drilling machine chuck guards.

I don't care what size they are, I can easily measure them if I need to. Making a cylinder square is only worthwhile if you start with ground stock.

That's why I deleted that line before you posted.

I cannot identify Brian's VFD from the pictures and recon it would be better to bin it and get one with decent instructions, here is an example of the guide in pdf printable form for the VFD I bought:https://inverterdrive.com/file/Schneider-ATV12-Easy-Start-Guide

Edited By old mart on 07/11/2019 22:17:10

We are close to finishing the Tom Senior light vertical at the museum. There is a bit of play in the X axis which requires attention, and the Y and Z aren't great. I have been conducting tests on the spindle which runs better than expected, and is now trammed square and is also square in the fore and aft axis.

Problems started when I started checking the Z axis moving the knee up and down. A dti was fixed to the column and one of the 2-4-6 blocks was clamped square to the bed Xaxis. The knee was sloping by about 0.010" in the 6" of the block.

It turned out that the pair of 2-4-6 blocks are not dead square. They both are three dimensional parallograms. They not only lean sideways, but fore and aft also. What clinched it was putting the long MT2 test bar in an R8 holder in the spindle. Including the taper, it is 11" long. and I have it running 0.0002" tir at the top and 0.001" tir at the bottom. When I set the blocks against the test bar it was obvious that there was a problem with the blocks.

On the surface table, the lean is easy to see with my square and even more obvious when toe bottoms of the blocks touch and there is 0.020" gap at the tops.

I also have some of the cheap 1-2-3 and 1-2-4 blocks (metric), surprisingly, they are actually dead square.

If I was still working, I could have got the blocks trued up by the grinders or the toolmakers in a jiffy.

You would have to be the unluckiest person to have the inverter fail to respond to the stop switch at exactly the same time as you caught your arm in the works. I will not be worrying about having the two extra latching stop switches in series with the regular remote stop switch, especially as they are in places which are easy to reach. When one of these is pushed, the mill cannot be started until it is reset.

Edited By old mart on 07/11/2019 21:21:41

I cannot get the link to work. Is this a recent programme?

The machine will stop quicker ramping down than if it just freewheels if the power is isolated from the VFD. The emergency stop buttons I have fitted are in positions where the operator can reach them easily, I cringe when I see somebody's machine with nothing but the tiny buttons on the VFD controlling it.

Edited By old mart on 06/11/2019 21:31:22

It didn't start life with that 0.10075" slip, but I wouldn't worry about 1/2 of a tenth of a thou, half a thou is a much more realistic measurement for the real world. Anyone who says that they work to 0.00005" is either a liar, or delusional.

Sets of slips usually have a pair of 0.1000" wear slips in them, or the metric equivalent metric size.

I noticed that a good many people removed their chuck guard because it was badly designed, or just got in the way. Nobody seemed to think of designing and fitting an improved one.

This thread makes me think of parents taking their kids for a bike ride and dutifully fitting cycling helmets to their kids heads while going bareheaded themselves.

It just shows how the Mitutoyo has been copied, if that top part fits. The main difference between the cheapo's and the Mit, is the superb fit and smoothness of the mechanical parts, well worth the transplant.

 My Mitutoyo 6" is 29 years old and beats all of my cheapos hands down.

Edited By old mart on 06/11/2019 20:47:50

I bought an inverter from a firm which also had quick start guides in pdf form which showed exactly how to wire in remote switches and potentiometers. I added two emergency stop switches in series with the regular stop switch. Anyone who just goes out and buys this sort of device without doing research first to find out whether the instructions are understandable for anyone who doesn't have a degree in electrical engineering is in for a shock.

If you post the exact model of inverter you have, I will see if a quick start guide is available for it. Every make has its own exclusive connections and programming, so a general guide is of very little use.

 Just adding a switch in the power supply is better than nothing, but the motor will stop quicker if the inverter is set up correctly, with remote switches. Never put a switch between the inverter and the motor.

Edited By old mart on 06/11/2019 20:15:39

Edited By old mart on 06/11/2019 20:19:46

I bought a 180mm cut off grinder from Lidl earlier in the year, everything is good except the clamping vise is poor and needs looking at. The only possible drawback of grinding is the localised heating which could be a problem.

When I bought my 7 X 12 Warco mini lathe, the original owner had bought a parting off holder for the tapered HSS blades. Unfortunately, he had fitted the blade upside down, which was worse than a parallel sided one.

Excellent plan, go for it.

The type of bed design should make them quite economical to have a regrind. Only top, back and front.

Edited By old mart on 04/11/2019 19:52:58

I have just found out that Gloucester tooling sell the iso30 boring head shank on its own. The thread is 1 1/2 X 18. They may be hard to drill and bore, but the thread would come in useful, as you might add more than one different length of extension to the shank for different quill travel requirements with bores matched. 

Edited By old mart on 03/11/2019 20:52:03

Shame its a 40 size, I wonder how it is prevented from spinning round if you let go of the handle?

It would be too long even if it was a 30 fitting.

Didn't you read or understand my post? I said that inserts intended for aluminium are also very good for steel and CI (CAST IRON) using small depths of cut. Therefore putting less strain on the tool. Less strain means less flex on a tool which is having to bore a deep hole. Saving money by using the firms ancient tools is all well and good, but a compromise.

Out of 14 SSD's that I have bought, from 32 to 500 Gb, only one has failed, a 120 Gb. I have had 4 hdds fail over the years. If I was going to buy a new pc, I would look at what Novatech have to offer in the UK. Or something like this if second hand:

**LINK**