Member postings for Andyf

A dummy spindle nose comes in useful if you want to turn something which screws on to your real one. For example, if you want to make a screw-on ER collet chuck, you can test the thread, and then the register diameter, without removing the job from the chuck. Once right, you can fit the embryo collet chuck on your real spindle and machine the taper etc, thus keeping everything concentric..

Andy

My old Dore Westbury has a round column. Tramming on the X axis is easy. because the head can be tilted, but tramming on Y involves shims.

If precision is essential, I check the tram. I'm not sure if the column is dead straight, so while it might be perfectly trammed at one height, that might not be true when the height is changed.

If shimming is needed, there's a nice way of finding what thickness is need on page 6 of this PDF.

Andy

The expression "white metal" seems to cover a multitude of alloys. Even "Babbitt" as used for bearings seems to have been formulated to various recipies over the years.

All I really can add to this discussion is that some sort of "white metal" was (and may still be) used for big end bearings on i/c engines, including car engines running at rather more rpm than the spindles on Myford lathes while (I imagine) being subjected to rather more stress, if only from the hammering given to them by the pistons.

Andy

So am I, Michael, now you mention it.

Should be 16tpi, for an imperial leadscrew on a mini-lathe. The 0.00078" advance is right, though.

Memo to self: turn the computer off well before 00.40am, and go to bed.

Andy

A correction to my post of 15 October (third in the thread). Should read:

"... or 0.00078" if your leadscrew is 12 TPI."

Andy

I would suggest a KB Electronics drive. I fitted one to drive a 2hp DC motor (complete overkill on power, but the broken running machine it came from was £15) on my old milling machine. It has been very satisfactory. The model I used was the KBIC 240, good for 2hp but perfectly OK for smaller DC motors in the 180VDC or so range, if the appropriate "horsepower resistor" is fitted.

Received wisdom is that KB boards are better than Chinese ones.

Manual for the KBIC series is here, with details of the variants on page 8 and the horsepower resistors on page 9.

Details of suppliers can by found by clicking "international" at the top right of this page; when asked what country, specify England rather than UK, if that's where you are.

Usual disclaimer. Just a satisfied user.

Andy

For what it's worth (0.5p?) I think the variety of our opinions reflects the evolutionary way in which things mechanical have progressed over the centuries/millennia, making it difficult to point to any single invention or advance as being The Great Leap Forward. For almost every development which is postulated, it seems possible to say thet it would not have happened without some previous invention or discovery, until you get back to things like smelting bronze and iron. But even then, the first bronzefounders may have used flint tools to get their firewood.

Andy

I'll second everyone else's advice: ER collets, each of which will compress down by 1mm (0.5mm for the smaller ones) combined with a bolt-on collet chuck, would serve you well. Very good for holding stock on the lathe, in addition to gripping milling tools.

I have a set of ER25s (the 25 refers to the o/d of the collet at its widest point; the capacity of the biggest ER25 collet is 16mm), with a bolt-on collet chuck for the lathe. My old miller has a Myford nose thread, so I bought a screw-on ER25 chuck which screws on, thereby avoiding the heavy whacks sometimes needed to free tooling from its internal MT2 taper. If you do buy a miller, R8 tapers are much easier to free off.

But as Joe says, expense can be considerably reduced by making up your own holder holder. Here, the milling cutter is only retained by a grubscrew so it would be as well to go for one with a flat on its shank, and to pull the tool forward as far as the grubscrew and flat will allow before finally tightening up. Otherwise, the tool might try to screw itself into the work and drag itself forward in the holder.

Andy

Hi Gary,

To get finer control of the depth of cut, a handwheel on the end of the leadscrew is a great help. But if you haven't added one, fit a gear on the LH end of the leadscrew and rig up some sort of pointer. If you use an 80T gear, advancing it one tooth will give 0.0185mm carriage movement on a 1.5mm pitch leadscrew, or 0.00078" if your leadscrew is 12 TPI.

It helps to have a lock on the saddle, but a G cramp to hold the saddle to the bed would suffice.

Andy

I must get one of those 23-jaw chucks, Neil. The all-round grip must be nice and even - almost as good as a collet, I hope they are self centring; independent might be a bit time-consuming to set up

Andy

For Vulcan fans, from YouTube

Early film.

1991 film., showing how quick they were at getting off the ground

Andy

There was a Vulcan indoors at Duxford when I visited 6 years ago, Ian. A fellow university student (in the 60s) joined the RAF, and his name (as a Flt Lt) topped the list of crew members stencilled on the belly of the fuselage. He was the pilot of the Vulcan which bombed Stanley Airfield at the beginning of the Falklands contretemps. I don't know if that Vulcan is the one from the raid.

Andy

OK for me too, using XP with IE8 and also with Chrome.

Andy

This might work: to avoid fastening anything to the bench legs, you could try standing their feet in the cups which are sold go under the castors of furniture. Put something rubbery in the cups, like a few layers of offcuts from rubber matting.

Andy

Windmills and waterwheels might have a place on the list, harnessing natural energy to do useful work, and coming well before the first practical steam engine, being that of Newcomen in 1712.

Andy

Noise and vibration go together. Try Googling "anti vibration mounts" for rubber-type feet to go under the bench legs. Also, walls can transmit noise and vibration, so leave a slight gap between the bench and the wall.

There will be plenty of washing machines in the flats, and your lathe probably won't be as noisy as one of those on its spin cycle, but the noise will probably go on for much longer.

Much will depend on the floor. Floorboards on wooden joists will act as more of a sounding board than concrete. My lathe is in a spare bedroom with a normal boarded floor, without any sound precautions. I have just set it going and listened in the room below. The hum was quite audible, and I would be annoyed if I was in a flat and the lathe belonged to an upstairs neighbour, particularly if he was making an interrupted cut.

Andy

If you are happy with the one you've got, it wouldn't be a bad idea to get another Comet, particularly if you have "extras" like a 4-jaw chuck which you could easliy swap between lathes.

Andy

I removed some last week by using a drift from the underside. The drift just fitted in in the hole, and all but one responded to gentle tapping. The awkward one had to be pressed out in the vice. There was minor damage to the undersides, which are chamfered down to almost nothing, but they still work OK after being gently tapped back in from above.

Andy

You are right, Michael. - the Swiss make some beautiful machinery. I just wish I could afford a quality milling machine like this, also by Aciera, on YouTube. But with me as the operator, it would be casting pearls before swine.

Andy

It's one belt, and the spindle pulleys contra-rotate because of the crossover. . The fork between them may push the whole spindle pulley assembly up or down, to engage one pulley or the other with the spindle, perhaps via a dog-clutch above the upper pulley, and another below the lower one.

Andy

Edited By Andyf on 05/10/2012 12:29:12