Member postings for old mart

I built up the spindle in the quill the other day. I gradually tightened the bearing adjusting nut, but was unsure if I had reached the point where the preload started. So I slackened off the nut and pressed the spindle to slacken off the bearings. I then set the quill on vee blocks on the bed of the drill mill and clamped it lightly with card between the quill and vee blocks and clamps. With it fixed, it was easy to creep up on the point of bearing contact and add about 10 degrees of preload.

The head is fitted on the mill and we built it up in situ. With the quill in place and locked in the up position, we figured out by trial and error how to tension the return spring. You fit the pinion shaft and connect the outer end of the spring, then carefully slide the shaft out until it just clears the rack on the quill. You can then wind it up until the od of the coils just allow the cover plate to be fitted.

I have removed the needle roller bearings from the pulley housing, as they will be easier to clean, and I want to replace the button oiler with a grease nipple. There are three sizes of button oilers on this mill, 3/16", 1/4" and 5/16".

I had to bore out the end of the motor pulley, as the current motors have a larger 24mm shaft. It couldn't be a simple job as the smallest pulley was only about 25mm at the bottom of the vee. I turned a steel bar down and pressed it onto the small end and used that as a mandrel to bore the other end. The finished wall thickness of the bored end was only 1/4", so I have fitted a collar, so the grub screws have a decent length of thread.

I am thinking of getting one of the 125mm wheels from RDG on ebay UK, 351115443777. It has a 12mm bore that could be increased quite easily. The Tom Senior light vertical X axis has a nice balanced handle, but I prefer a round design that can be held in both hands at once comfortably.

This is the weakness of a design with exposed gears, you have to take care not to drop then in the dirt.

That's exactly what I was trying to explain, David, thanks for the endorsement.

I agree with JohnF with the dark straw, or even a little past that into blue-purple. They need to be tough and not brittle, rather than hard.

If a foreign body gets trapped in the rack, the pinion would be destroyed if there was no allowance made to spring load the pinion shaft. Outside of a clean room, shit happens.

You will only know if a collet is good if you repeat the fitting with the collet at random positions and then take an average runout.

Dial calipers have a rack which meshes with a gear that drives the pointer. Sometimes the gears jump a tooth or more, resulting in the pointer not reading zero when the jaws are shut. I am guessing, here, but the tool may be for tipping the spring loaded gear out of mesh with the rack, to get the pointer reset. I had a Tesa dial caliper, but that was 40 years ago, and my memory is not great.

Somebody will be able to post some photos showing exactly how its done.

What a wonderful freebe. Try a Stanley knife blade on the rusty cast iron, you may find there is not much pitting at all.

A lot depends whether the hole is blind, how deep, or a through hole. All reamers have a lead in angle, or they wouldn't work. A hand reamer has quite a long shallow angle lead in and would be unsuitable for use in a short blind hole as about one diameters length is tapered. A machine reamer has somewhere in the region of 1/4 diameters length of taper. If you are not very experienced in using a reamer by hand, the hole will end up bellmouthed, so using a machine, or a pre made guide will help to keep the reamer straight, turning the machine by hand, unless a very slow speed is available. A reamer can be made to cut different size holes, without resorting to butchery of the reamer. The smallest size is achieved by copious amounts of cutting oil. The intermediate size is by oiling the reamer and wiping most of the oil off with cloth or tissue. Reaming dry will give the largest size, although usually a poor finish at the same time.

Solid carbide drills used correctly will give a hole to size and finish without any need for subsequent reaming.

I have a tiny 7 X12 Chinese lathe at home and was annoyed at the amount of tailstock projecting when the MT extracted. I cut off the MT2 tang from the 1/2" chuck (too big for a little lathe) and drilled a hole in the end of the taper, just large enough for the tailstock leadscrew to enter and a little deeper so a brass plug sits at the bottom of the hole and now I get over an inch of extra travel.

If your chuck is on a backplate, separate them and check the face of the plate. Double check the cleanliness of the fitting to the lathe spindle before any skimming of the faceplate. 

Before doing anything, remove the jaws and check that the face of the chuck body is true with a dti.

Edited By old mart on 17/08/2019 21:09:03

Surely with that design the oil is fed to the main bearings and some is centrifuged out to the big end. It couldn't work the other way round.

Take the offer of spark erosion and cough up the money.

I have that problem with some battery drills. They won't fit in the box if the jaws are projecting from the face of the chuck.

The current standard of plugs and sockets was definitely in use by 1960, as we moved into a tudor cottage which had just been rewired. The wiring was pvc, it had a 4 way consumer unit made by Wylex and a French made Chilton 500mA earth leakage circuit breaker. It wasn't easy to buy plugs at first as it was all so new-fangled. I took one of those old fashioned Chilton elcb's apart a few years ago and the design was similar to the modern rccb's .

The spindle is now one piece using the Loctite 620. The quill and outrigger lower bearing were done up tight and Rod drilled and tapped for a 2BA grub screw to make sure nothing comes loose in the future, unless we want it to. I got a 400mm length of 7/16" 431 stainless steel for the drawbar and singlepointed the ends 7/16 UNF. I also reduced the centre part with a 0.005" cut using an insert designed for stainless, which cut beautifully. The stainless grade insets I have are halfway in sharpness between the blunt steel and the sharp aluminium type. The drawbar was too good a fit in the spindle and needed a little clearance.

I had some trouble with the bronze threaded extractor collar. I had to screw it about 1 3/8" along the drawbar and it started well with loctitite 290, but only got halfway. I had to use a hot air gun to unscrew it and start again using the 620, which just succeeded. It was also getting tight over the last 1/4". I think it must be the viscosity of the Loctite causing local heating when a long length of thread is screwed up.

I used to have a cheap copy of that sharpener, I gave up using it as I couldn't manage to get both flutes to match exactly.

Its not much good asking me about oiling a lathe. I lubricate the Smart & Brown at the Helicopter Museum with cheap semi synthetic motor oil, and the purists would wail and tear out their hair to hear that. It gets plenty, and the 70 year old headstock bearings are perfect and there is only 0.0005" wear on the spindle.

Hi, Tim , welcome to the forum.

Regarding the headstock bearings, assuming they are adjustable plain type, there are a couple of clues. There are rings at the front and rear of the spindle which are supposed to be adjusted with a peg or C spanner. They have the usual marks of a hammer and drift. If you take the cover off the headstock, hopefully you will see two more of these rings either side of the casting. The ring behind the chuck may be a little larger diameter than its counterpart immediately to its left. If it is, then by slackening off the larger one and tightening the smaller one, the bearing is moved slightly to the left, and becomes tighter. The left hand spindle bearing is adjusted in a similar manner, by slackening the larger ring and tightening the smaller. Assuming that there is play in the spindle, it would be advisable to only adjust one end at a time. Plenty of oil is needed for the bearings, and you can probably feel them tightening up. not too tight though and the only way to be sure they are not too tight is to run the lathe and monitor the temperature of the headstock in the area of the bearings. Just warm after 15 minutes is what you are aiming for. There look like the remains of the headstock oilers on the top cover, which will have to be sorted out.

An early Colchester owner may reply to your question, hopefully.

Edited By old mart on 13/08/2019 20:39:49

Edited By old mart on 13/08/2019 20:41:53