Member postings for old mart

Fine swarf can get into motors and cause earth faults before the big bang.

If you use a single phase 230V domestic power source for the VFD, then its best to keep to a maximum of 3hp for the motor. Three phase motors come in several guises according to how many poles they have.

2 pole- 3000rpm, 4 pole- 1500rpm, 6 pole- 1000rpm, 8 pole 750rpm, approximately at 50Hz.

Modern motors can usually run faster than standard, I bought a 6 pole motor and run it from 25-75 Hz, between 500 and 1500rpm.

You need to make a note of the rpm of your motor and choose accordingly.

Here is a link to Inverter Drive Supermarket, their "quick start guides" are excellent for making the wiring and VFD programming easy.

**LINK**

We get our gas and electricity via British Gas and have two "smart" meters. Not quite so smart when I have to take manual readings from both over the last 18 months.

Read and understand mgnbuk's post about where the strength of this type of belt comes from.

Remove the drawbar, check the threads and cut a short section of suitable bolt with a screwdriver slot added to screw into the end of the stuck tool. This should be screwed in at least 1 1/2 diameters and show in the slot, so measure carefully first. Then your wedges will extract the tool easily.

Due to the very high prices of fixed steadies for Smart & Brown model A lathes, I bought 2 at different times on ebay, one small for up to 2" diameter and the other larger which can take about 3 1/2" and with a hinge. They were for Chinese lathes and having a mill at the museum, I cut the original bases off, and machined them to bolt on aluminium bases made to fit the lathe. The larger one has bronze fingers with screw adjusters and I made another set with sealed roller bearings to add versatility. If you have milling capacity, that is the best way to go. They both bolt to the side of the aluminium bases and can be bolted either side to suit the job in hand.

I was going to suggest going to a scrapyard and buying some cast iron, but Noel's garage brake discs is an even easier source.

They have their uses, particularly for users of hss tooling, as there should not be any bother with shimming after every sharpening to get on centre height. We have avoided QCTP's at the museum, all our tooling is indexable, holders are milled down to centre height, or boxed with custom made shims for smaller boring bars. Having a choice of over 50 tools would be rather expensive and space consuming if QCTP's were used.

A quality drill, and in good condition, to boot. There is information on these machines in the Lathes UK website:

**LINK**

A drilling machine which uses Morse taper usually has an extraction slot for a wedge to remove the tooling. Very few mills have this feature, unfortunately. Morse taper mill fans are always people who are stuck with one and try to justify its shortcomings by telling potential mill buyers it is perfectly satisfactory. I repeat, as usual, if you are in a position to choose between Morse taper and R8, go for the latter.

I certainly hope that people considering buying a new mill read this thread right through before choosing a Morse Taper spindle. These threads repeat several times every year.

With a smaller mill, you may loose some Y axis travel if the X axis encoder is at the rear of the bed. At the front, it might interfere with the X axis stops.

If the mill looks cared for and not abused, it should be fine. We have a round column mill and a Tom Senior knee mill at the museum, and the only real advantage that the TS has for me in my old age is a higher bed which means less back strain.

Welcome Richard, if you make your own stand, it can be much stronger than the tin boxes that cost £300. Also it can fit your workshop better.

Whether a holder has a shim under the insert depends entirely on the whim of the manufacturer. The shim is to protect the holder from damage in the event of a pile up. I have holders for single and double sided inserts, some with shims and some without. Some of the high end holders, Sandvik, for instance have shims, but not universally, even for the identical insert. High end shims are usually carbide, but the cheap Chinese holders have steel shims. Shims are not identical, different clamping methods would use different shims for the same insert.

Over the years, I have bought lots of indexable tooling, and I have engraved the insert codes on the side to make it easy to select the right replacements.

Edited By old mart on 16/08/2022 20:26:28

I have looked at the picture and think it is VM on one side and 04 on the other. Unfortunately that is more likely to be a mould number than a grade. If you look closely at the sides of the insert, there may be a laser engraved code which would be a grade. The insert is certainly for steel, but grades for aluminium are also easily available, I have both plus stainless grade which is halfway in between.

I have had some good deals from the JB site on ebay.

Here is a link to the APT relavent page, unfortunately the SNMG12 inserts are too big to be included in their list of hobby machinist inserts which are available in smaller quantities than boxes of ten. The Cutwel page is very useful to identify various shapes and sizes of inserts.https://www.shop-apt.co.uk/carbide-inserts-for-turning-apt/page/2/

Edited By old mart on 15/08/2022 18:54:57

Edited By old mart on 15/08/2022 18:56:48

I saw that and made a small contribution as I have benifitted greatly from the help available and would like to continue to get advice.

A fortnight ago, I had a text inviting me to book a flu jab along with the second covid booster. When I had to actually go to the surgery last week (because the NHS website is impossible to navigate and the phone line is specially difficult), I was told that there were no places left and I should try again in 10 days.

If anybody gets an invite, be sure to get book up straight away.

Anything printed on an insert will be the grade of carbide. Would you check the name of the inserts? SNMG1204 may be what you have, a common square shape, neutral, double sided and 12.7mm width per side and 4.76mm thick with 8 corners per insert. They are good at 45 degrees as a chamfer, but cannot face up to a square edge. The holder is 20mm square section.

You are talking about tarnish to the zinc, I presume, corrosion of the steel beneath would be brown rust coloured. Zinc can be passivated like cadmium plating, this link may help.**LINK**