Member postings for old mart

TPAN is very old technology, the numerous adverts for 50mm shell mills using four APKT16 are a better bet. Inserts for steel and aluminium are available from the cheapest Chinese, to premium makes. The Chinese inserts are pretty good these days.

Here is one of many on ebay UK. 1630941344584

Glanze indexable lathe tools are in the higher quality sector, I can recommend them.

What do you think of the Warco at the centre? They do a range of smaller models, although I do not know if they ship to Ireland.

My only experience of live steam, was as a teenager, getting hold of a Mamod oscillating, very basic, stationary engine. The first thing I had to do was replace the rubber seal in the filler/safety valve, the blow off seal, that is. There was no way of checking the actual pressure the valve would work at with my carefully cut 1/8" long section of bicycle tyre inflator hose. I bent up a length of copper tube and soldered it to the exhaust port and through a hole drilled in the dummy chimney.

I'm pretty sure the boiler was made of brass, I thought that de-zincification only occurred in a salt water environment, which is why bronze is used.

At the museum we now have two plates, the first one is a 12" square of float glass stuck onto a 14" square piece of chipboard with some 1/4 round beading glued round the edge. It does the job admirably , especially for small jobs.

The second is a 2 foot square surface table which I bought on ebay for £50, which I collected from about 30 miles away, it just fitted in the back of my Corsa. It is heavy, my left arm is still bad after four months.

I have no plans to retire the glass plate because it is still very useful. If anyone gets a glass plate then I recommend not sticking it down too permanently, as it can then be turned over when the first side gets scratched. I had the cross slide of the lathe on the glass sitting on two 123 blocks. When I lifted the slide off, one of the blocks stuck to it and then fell 6" onto the glass without breaking it. It took a chip out of the glass surface, the plus side of this is there can be no burrs unlike a cast iron surface would have.

Have you tried out the chuck on a lathe? Do the jaws fit well in the slots? I find it very difficult to believe that someone managed to assemble different manufacturers parts, especially as they don't seem to be in a worn condition.

I bought a Vertex electronic edge finder years ago, it has a 20mm shank, and a 10mm spring loaded ball. The shank size will be too big for smaller machines, but if you can manage that size, it is recommended. They are not intended to be used with the machine running. Identical versions are available cheaply on ebay, see listing 263808616504.

Myfords are ok if you don't mind paying extra for the name. Boxfords are a less expensive, heavier duty lathe.

I've never needed differential calculus since leaving school.

Have you tried all of your collets for consistency using undamaged drill shanks, or milling cutters? If the average is only 8 microns, then its best to leave well alone. If you have a longer test bar, and that is ok with several successive fitting and refitting, turning the collet in the nut each time, then what you have is as good as it gets.

The lathes UK site has the manuals but they are not cheap at £45.

That shell mill is a bit big and sticks out a lot from the spindle. The skin on the cast iron is a real problem. I think you are exceeding the capabilities of the machine.

Some years ago, we had contractors at the museum putting insulation and a second skin inside part of the building. They were cutting the modern corrugated steel with 9" angle grinders. These panels are only about 0.025" thick, but one of the younger lads managed to get a bad kick back and the disc skimmed the side of his arm. It did very little damage, just abrasions mainly. It was his first accident with the grinder, I hope he learned to respect the tool, as he was very lucky that day.

At risk of wandering off topic slightly, If you use carbide insert parting off blades, all the manufacturers recommend that the tip height is set 0.004" high if used for parting solid stock.

The two flute slot drill can cut downward (plunge) and is recommended for cutting a slot like a keyway because only one of the flutes is cutting at any time. This puts a strain on the side of the cutter in one direction. Four flute cutters are commonly also available in a downward (plunge) configuration, but are not recommended for cutting slots for the following reason. Having four cutting edges means that two of the flutes at 90 degrees spacing get to cut at the same time, bending the cutter and producing a slot wider than the same size two flute slot drill. A three flute cutter just misses the multiple cutting problem, but is harder to find. Standard end mills do not cut in their centres and can only plunge a small amount, say 0.5mm for a 12mm cutter.

Being stiffer than steel, four flute end cutting solid carbide mills are better for keeping the slot width to size. For precision, it is best to use a size of cutter smaller than the slot and creep up on the width using extra passes.

Three jaw self centring chucks are quite different mechanically from four jaw independent ones, so the way they are attached to the backplates varies. There are chucks made to fit directly onto Myford spindles by doing away with the backplates and screwing the chuck body straight on. The advantage of this is the extra couple of inches gained, and increased stiffness. 

Edited By old mart on 16/07/2019 17:58:37

I don't remember the launch, but certainly the landing.

There is a very good film called "The Dish", based on facts that have been forgotten regarding the Apollo 11 story.

Those torx screws are not all that hard, so drilling the head is possible. Just look at a spare screw profile to see how deep to drill. The edges if the drill will be the worst for wear after hitting the hole in the insert, but its easy to re sharpen a drill.

As for cracking the carbide tip, don't just hit it, put the tool in a vise with the insert away from you and use a drift or chisel to stretch the screw a little. Do not try to knock the insert off, just loosen it. then the screw should turn easily.

Mechman 48 has the method I would use, if there is any concern about overheating, score deeply using a diamond file all round before snapping off. The advise regarding the cloth is particularly important.

These problems with parting off are so very hard to figure out.

You may have had too much speed for steel. I would run 100-200 rpm.

Something may have moved. If there is a choice of three or four jaw chucks, always use the four jaw chuck.

A properly set up tool height gauge is better than a drill in the tailstock and can be calibrated using a lathe tool which faces off exactly on centre.

Check your jibs on the cross slide and compound for play.

Lock the saddle when parting.

I still have problems, even when using modern industrial parting off blades, 26 and 32mm in specially made dedicated toolposts, also inverted rear toolposts fixed directly to the cross slide with rear saddle lock.

A lot of that stuff will respond best to a bit of wire wool and 3 in 1 oil or WD40. Use thick pvc gloves.

 If the faceplates are to be used in a lathe, then a light facing off will kill two birds with one stone.

Edited By old mart on 15/07/2019 22:53:16