Member postings for old mart

I have cut the tang off of some Chinese MT2 arbors which have chucks on them, with a hacksaw, and drilled into the small end with no bother. I'm sure they would tap also.

This was to shorten the taper so it would not extract prematurely from the tailstock of my small 7 x 12 Chinese lathe. I got extra tailstock travel for my efforts.

Edited By old mart on 16/09/2019 13:15:21

I always recommend the Motalia website for info on threads:

**LINK**

Edited By old mart on 16/09/2019 13:06:47

I went down the local dump (recycling centre) the other day and they had a six yard skip overflowing with old televisions, at least 90% crt . A few years ago, I took a perfectly good 17" monitor and a 28" Sanyo flat screen tv down there, nobody wanted them.

Bad luck, Ian, try to remove that bearing without damaging it, or you will be buying yet another. I made a similar type of mistake yesterday, I pressed two parts together and left out one procedure which would have been much easier to have done before they were assembled. Instead of taking a minute to do, it will take me 1/2 hour just to set up.

It should work, although I have only cut case hardened, not HSS. Use the highest speed you can, and cut dry. I did use a carbide drill to remove a broken tap with good results. Do not touch down on the work with the cutter stationary, you will chip the flutes.

When I carried out the R8 conversion, I had to put spanner flats on the bottom of the spindle as there was no way of holding the spindle when the drawbar was tightened and released. Holding both ends securely enables better tightening, and at the same time, I made the drawbar captive which is also a great advantage. No hammering to break the taper, and I also elected to run without the locating pin in the spindle. The only downside of a captive drawbar is that a few MT tools in R8 adaptors used a different drawbar size, which would mean removing the 7/16" one if I use them.

I agree that the R8 collets give you more Z axis space, but they don't get used very often, unless I put a 20mm shank tool up.

I was surprised that the op's choice was between MT2 and ISO30, the R8 comes in between them usually.

I have just gone to a lot of work modifying a Tom Senior light vertical from MT2 to R8, which is a superior fitting. I would prefer ISO 30, but the conversion is much more difficult, and I already have lots of R8 tooling.

Be aware that shot blasting thin sections can cause distortion, the blasted side will end up convex, and even if you blast the other side, it is unlikely to go back flat.

If you are fitting bearings where the inner and outer races are in line, then using a tool which presses on both at once cannot cause any harm. Taper rollers do not line up when they are assembled, but because they come apart, it is normal to deal with each part separately.

I have bought dozens of things from China on ebay, with very little in the way of problems, they average 9-12 days.

Stoning the face that way has a similar effect. I think the op's problems stem from trying to feed too fast.

You could do without a powered cross slide, but getting the saddle connected to the leadscrew is important, but usually only needs the leadscrew nut/s to be working. The gears that move the saddle along the rack are important. The gears that power the leadscrew which live at the left hand end of the lathe are frequently missing, but are easier to replace. I have removed all the hard to get change gears on the Smart & Brown Model A with similar size easy to obtain mod 1 metric gears. This is possible because at the left end of the lathe, the gear spacing is adjustable to accommodate different tooth counts.

Blowlamp, your drill on the left is a split point, not a special brass/ bronze one. The relief angle is the same as the one on the right.

I have a couple of pictures of a drill bit that has been backed off, it needs sharpening.

Thread rolling is a specialised process, which most firms would sub out to the experts.

Jizer or Gunk are water washable degreasers which are unlikely to damage paint.

ISO 30 is a proper milling spindle size, Morse tapers were designed for drilling machines.

I will try to remember to take a photo of a drill tip which has been backed off, tomorrow.

There is a UK company selling metric leadscrews and nuts, but not in 2.5mm pitch:

**LINK**

 I have looked everywhere for 2.5mm pitch trapezoidal, and cannot find any, funny as your Boxford is not alone, the drill mill at the museum uses 2.5mm pitch screws on the X and Y table travel, although they are much larger diameter than yours.

Edited By old mart on 13/09/2019 16:34:30

If all else fails, just get a 12 X 3 trapezoidal leadscrew and nut and graft it onto one of your existing ones?

**LINK**