Member postings for old mart

You can easily check if the screwhole is vertical by screwing the screw underneath a couple of turns and eyeing it up. In a tool like yours with a positive insert, the insert is horizontal and the screw is offset slightly so that the insert is pulled tightly into the machined recess when the screw is tightened. Your idea of producing a recess on the other side of the holder has merit, and only the difficulty of small scale precision milling is against it. Most of the common positive inserts have sides sloping 7 degrees and the pocket in the holder has sides to match, that is difficult to reproduce.

Looking at your photos, I see a problem, there will not be much thickness left with such a small tool if there are pockets on either side.

I have machined loads of indexable tools to get them all the same height and can say with certainty that Sandvik, Kennametal, Seco, Korloy, WNT, Mitsubishi, APT, Iscar, Walter and the cheap Chinese ones are equally hard. Not so hard that they cannot be filed or cut with a hacksaw, but carbide tooling is the best way to machine them.

The Chinese toolholders readily available are so cheap, that unless you want to modify your existing one as an exercise, then simply buying a left hand one is best.

Edited By old mart on 04/09/2020 17:56:41

Make sure you have plenty of straps to secure it and blocks to stop the base moving. Just take the tailstock off, and move the saddle to the far right and lock it.

When we did repair work on the Smart & Brown model A at the museum, I made a new leadscrew nut out of gunmetal, and to keep most of the swarf away, I bought some telescopic tubular springs to cover the leadscrew. I'm glad I did as the leadscrew always looks like it has just been washed. You just pull back the spring each side of the apron and squirt oil over it every six months.

They are available on that website we are not allowed to mention, so no helpful links from me anymore.

PB used two types of thread on similar sized chucks, square and ACME. You can compare the teeth in the jaws to easily check. I was in the process of repairing a very worn 6" PB and after making four screws, I was dismayed to find that the plugs which you are in the process of removing were all cracked. This prompted me to give up and I got very lucky buying a NOS Toolmex for just over £106. The square holes are smaller than PB ones, and consequencly, the ends are less likely to crack.

I always use a strap wrench to unscrew the chuck, and never use a "cheater" for more key leverage.

Torque?

I would feel safer if the 8mm size could be increased to at least 12mm or better 14mm. Whatever you do, take small cuts, and as both ends will have to be faced, then use tailstock support.

Oilite bushes can be bored to size, but reaming is not recommended. The reaming action tends to smear over the pores and impede the oiling.

SOD would look for 74 and 75 and I would look for 77 and 78.

If you use mild steel, the life will not be as good as hard material, but for home use it would be satisfactory. Polish the shaft where it passes through the bush. While you are about it, why not make an extra shaft, then you can be sure that the first one you fitted will last forever. Dont forget to oil the bush with a couple of drops regularly.

I would have some rubber pads under the feet and a safety strap attached to the wall behind. Lathes are top heavy and even a little clip on chain like gas cookers have would make all the difference.

As far as I can tell from the pictures and assuming they are single sided with sloping, not square edges, they are likely to be TCMT 09 for steel, and TCGT 09 for aluminium/ finishing stainless and steel. There doesn't seem to be an 08 size and the next one down may be 06 which is much too small. The size is the inscribed circle diameter which will fit in the triangle. These left and right handed inserts are rare nowerdays, you will be unlikely to get any. For most applications, the symetrical type which is common today is better anyway. Prices vary from silly overpriced big brands to the affordable Chinese ones which are very good.

Hi, Stan, welcome to the forum. You should start by spraying the chuck liberally with Plus Gas, AC90 or WD40 and leaving it for a few days. Some taps with a soft hammer and a lot of patience is what it needs. Sooner or later, it will start to move a bit, and when its apart, then scrape the rust off with a penknife, rather than abrasives, a few blemishes are preferable to something that just looks pretty. Oily wire wool and elbow grease is good for rusty steel without loosing the tolerances.                                                                             

Edited By old mart on 27/08/2020 20:49:43

I do it by eye, but it is very difficult to get them identical.

I mentioned 9" plates as they are common in various configurations wheras 10" are like hens teeth. Keep looking on that website that must not be mentioned.

Keeping the sheet flat will be a nightmare while it is machined. In industry, a vacuum plate would be used. I would go for HSS and buy several,making sure that a lubricant like WD40 or AC90 was used at all times.

My imperial Baty has a dial exactly the same cream colour as your photo, probably aging of the paint. Metric gauges will normally have a much brighter yellow dial colour.

The grub screws will probably be made of the same steel as high tensile SHCS (12.9) which are easy to cut with a hacksaw, so hss will machine and drill them ok.

Get another D1-3 backplate, modify it to fit your spindle, face it off and get hold of a 9" faceplate. Drill and tap the backplate so the faceplate can be bolted on backwards and machine the central part to fit when it is turned round. You will have to allow for reducing the backplate diameter to as small as possible when machining the back of the backplate, or you will loose access to the mounting slots towards the centre of the faceplate.

I have just performed a similar but simpler thing to an Atlas screw thread backplate, which is 1 1/2" thread and a 9" faceplate with a smaller threaded spindle fitting. I managed to get the backplate down to 3" diameter and use 8 x 6mm SHCS to hold them together. You won't be able to make such a compact boss for your faceplate. A tee slotted faceplate might be a viable option.

If your contact cleaner is a spray can, just spray a little into a small container and dip a large sewing needle into the cleaner and apply it locally with little chance of damaging nearby parts.

Be careful with electrolytic cleaning, do it in a well ventilated area, and treat any froth build up as an explosive, no sparks, especially electrical ones.