Member postings for old mart

I think you will be ok for home use, but sometimes a bigger chuck cannot hold much bigger work as the jaws are also bigger, and tend to hit the bed earlier. The biggest chuck a lathe can hold, safely, or not is the one that allows the maximum safe extension of its jaws to clear the bed. People frequently fit 125mm chucks to 7 x 12 Chinese lathes, I was happy with a 100mm four jaw independent on mine.

I saw this on the auction site and as the price was right, I couldn't resist it. It is an integral shank two flute 50mm NOS Maydown with 22 inserts included. They are an old style triangular shape which will give me 33 changes of edge. There was only one deciding reason to get it, the extremely low profile. From the large end of the taper to the tip of the inserts is only 36mm, none of the shell mills can get anywhere near that. I used to have a quantity of those inserts, but used them all up screwing them to handles for scrapers.

Thanks, the hole looks like 1 5/8" diameter, so there will be plenty of room for part of a nut down there. It looks like you will end up removing the bed and cross slide to get at the knee mechanism. I can say that the tapered gib for the bed is removed from the left hand side and the X axis wheel and both endplates for the X leadscrew have to come off, then the bed can be slid off easily. After that, the X leadscrew will have to be unscrewed to get at the Y axis nut holding screw in the middle of the cross slide. After that, I can't remember. The whole lot is pretty easy to dismantle, we took the mill to bits and put all the bits on pallets when the museum inherited it.

I have watched an expert scoring the circle with a diamond and then adding lots of radial scores. He then used some special pliers to snap off a bit at a time. The Maun pliers with the parallel jaws were the nearest that I could think of. Then he finished the edge with a linisher. I noticed that he touched on to the belt with the axis of the glass in line with the belt direction, and in the bit that is between the front roller and the top plate. This minimises the shock caused by the joint in the belt. Of course, he made it look easy.

Thanks, I had understood your drawing when I saw a photo of the boss standing proud of the drip tray. I would make another one shorter. I would appreciate it if you could block up the knee again and unbolt the boss and screw it up the leadscrew to measure the diameter of the hole the leadscrew sits in. If it turns out a close fit for the screw, then I will have to think again about the whole antibacklash and just use one new nut, which will be much better on its own than the worn out one in use now.

 I haven't found any way to rotate photos when posting, but that one was to highlight the loss of height when tall equipment is in use.

Edited By old mart on 15/11/2020 16:11:50

Too late again, I have found a photo of the mill I had forgotten about.

Too late to add to the last post. I have found some pictures of the boss which the Z nut is screwed to. I had forgotten that it sticks up from the tray. If necessary, I can make use of that height for part of the backlash mechanism.

They also sell 2 pole ones, that was just a link to their site.

I remember when single phase mains voltage was 250V, things change with time.

Edited By old mart on 14/11/2020 18:10:56

I cannot tell you how tight the dowels are that Smart and Brown fitted to the model A are, I have taken two compounds and the crossslide to pieces and have never disturbed the gibs.

 You would have to get suitable diameter and length dowel pins, then drill and ream the slide with the gib secured to it for exact alignment. The reaming would have to allow a sliding fit for the dowels which could be Locktited into the casting. If the gib is hard, then a solid carbide drill the same size as the dowels could be used without reaming. Seems like a lot of effort to me.

Edited By old mart on 14/11/2020 17:25:37

If you visit "the inverter drive supermarket" and look at their three phase motors, the amperage for star and delta are listed. Star is 440V and delta is 230V.**LINK**

That bourden tube is kinked and will never be safe to use, just take my word for it. The gauge will not be hard to replace anyway.

I thought that living next to Lancashire would increase your intelligence. Your earlier posts seemed to show about 75mm of thread above the nut when the knee was down. Then you say there is only 5mm, which I hope is the clearance between the bottom of the knee casting and the drip tray. The thoughts of a 1" raiser for the column is some way in the future. If I were to put the 6" rotary table with a 5" chuck on it on the bed, there is an immediate loss of about 10" of Z height, that is without the workpiece or tooling accounted for. One of the reasons that the drill mill is being kept is the 3" extra Z available.

A good machinist can get better results from a worn out machine than the rest of us using a new one.

I lived next to the A283 about a quarter of a mile south of the Surrey border, about a mile from where Warco now is. Back in the 70's, my firm bought a new Myford Super 7, and I think it came via Warco, possibly before the company started, the name Warren, Warner, or Warne rings a bell to me. The guy I bought my 7 x 12 came from Frome in Somerset and had travelled to Warco to pick it up.

I'm now in Weston Super Mare and my posts are about the machine tools at the Helicopter Museum there.

Edited By old mart on 14/11/2020 14:07:44

If the angle is the same as the BT type, and all the BT are the same, I wonder how the BT40 would look just offered up to your spindle? If you order one of the BT40 to BT30, try out the fit before doing anything else. An alternative solution might jump out at you.

You are likely to find the steel of one of these adaptors hardened, so HSS will not do. I would turn a male BT30 part for the adaptor to be attached to first. Getting the angle correct will be a nightmare, even if your lathe has a taper turning attachment. The fit needs to be within one minute of angle to work properly.

I don't think dowels will make much difference to the working of a gib. There is usually some method to stop the gib sliding endways, such as a countersink in line with one of the screws and a matching conical end on that screw. You would have to dismantle the compound to find out.

I took that compound to bits to replace the 70 year old oil/grease and the gib was securely attached to the body by the dowels. There is only about 0-0001" backlash throughout the travel, but I will be tightening the gibs as the whole assembly is too free moving for my taste. Apart from the dowel holes, there are no indentations for the screws present.

Smart & Brown gib fixings are flush with the surface, the nuts sit in counterbores. I have a tubular spanner for the nuts and use either a little screwdriver or a hex key on the gib screws.

Edited By old mart on 13/11/2020 21:05:52

I don't think any harm has been done, I would not have been content with only three screws. The high points are easy to deal with and its a compound, which gets less used than other parts of the lathe and can be kept a little on the tight side anyway. This NOS compound I picked up recently has six, and also two dowels, right near the edge.

Edited By old mart on 13/11/2020 17:51:16

Dead right, Simon, the problem is wear. The gibs are adjusted in the general most used part of the movement, and everything is ok until the knee is lowered right down for a tall job. I will address this when the knee is removed, but will only partially remedy the problem. I don't have the equipment or expertese to restore the ways to new condition. As the knee gib gets tighter near the bottom of its travel, the leadscrew starts to pull the whole weight downwards and as the nut has a lot of backlash, every so often the lot drops about 0.020", or whatever the backlash is. Having a quill, means that the knee movement is not essential for moving the Z axis while milling.