Member postings for old mart

Here is the Microplan 6 0.1 MET infinity objective, it is obvious why it needs extending from the turret.

Here's a pic of the microscope, with four NOS objectives, the total cost has come to £80. I had to get an adaptor made to fit the Lomo heads, monocular, binocular and the trinocular, shown, and the plastic adaptor for the 1W LED torch for the epi. The cheapo Chinese 5 Mp CCD would be better if I hadn't misplaced the driver disc. I believe that the iris diaphragms are adjustable, but hesitate to move them without some advice. The 20,40 and 100 have very little clearance when in use which makes the sprung noses very important. I would like to get an 80 dry LWD, but one of the Chinese ones on the market would cost twice my outlay so far. I have tried a Lomo 40 0.85 APO biological objective and it is nothing like as good as the Vickers on this type of microscope.

Inconel may work, but what about the electrodes used in a combi boiler?  These are Worcester Bosch p/n 87181070870. They are about 2 1/2" long and made to sit within the flame. Pity as a set of newish ones went to the scrapman only yesterday when my old boiler was replaced by a ned 4000 series one.

Edited By old mart on 05/09/2023 13:55:04

I have had a Lomo R25 for many years with many accessories which has just been dug out of a cupboard to play with. The extras include phase contrast, darkfield, adjustable offset condenser, as well as the original Abbey condenser. A couple of APO objectives in 20 and 40 X and eyepieces from X5 to X15, plus Kohler illumination. I have just bought a Vickers M12 body, epi illuminator and a set of Vickers objectives for it. The 20, 40 and 100 OI are all Microplans labeled MET and strain free. The Microplan MET 6 X is not quite compatible as it is infinity and I have ordered a 16mm parfocal extender as the top end of the lens fouls the inside of the turret and stops it rotating. I have fitted it in the working position and it works perfectly for my purposes. The parfocal extender will be vital as the short lens length even with its long working distance means the other objectives will foul the stage. The epi illuminator has had an adaptor made to take a LED torch and works well, except the two iris diaphragms are not exactly on the optical axis, should they be offset?

That is a common way of locking, you could make one easily, no particular precision needed either.

Have you compared the runout of all your different sized collets? APT sell er collets in several grades, presumably they had been had been tested individually and priced accordingly to their quality.

Edited By old mart on 04/09/2023 20:06:17

Clever design, I did not understand how the laser image presented a circular image and whether that image diameter reduced to a point when the axes were exactly at right angles in all planes. Particularly how the persistance of the projected beam worked. Normally such a beam would always only show as a spot, not a circle.

I came by about 10 polycrystaline diamond inserts which fit APHT11shell mills in a job lot of inserts. They only have one edge and are intended for machining high silicone aluminium. The got tried out and then stored away and forgotton. Not much use for them in the type of machining we do.

I checked middle of Lidl without result, but today in the smaller of the two Lidls at Worle near Weston Super Mare, there were two still for sale and I bought one. Thanks for the tip, we need to modify some existing tubes to fit another helicopter exhibits and the bender will come in handy, it is quite well made. It does 6, 8 and 10 mm pipes and will also get by on 1/4, 5/16 and 3/8 inch ones well enough for us. The pipes are aluminium.

It always makes me chuckle when somebody bends something straight.

Wouldn't the CAA require certificates for bearings such as these if they are to be used in an aircraft? I now notice that the bearings do not have to be airworthy, just original. I will ask questions at the museum, we have thousands of new bearings but for helicopters, and they will not be listed by the bearing size, but by the aircraft manufacturers part numbers as only the proper parts are allowed, not the generic names.

Edited By old mart on 03/09/2023 17:12:41

Edited By old mart on 03/09/2023 17:18:33

I have an 8" digital height gauge and a 6" digital caliper of that make and can throughly recommend them. The Dasqua 6" digital caliper is as smooth as my Mitutoyo and Tesa's, larger numbers and 1/3 of the price.

I have one at the museum and used it the other day for a similar boring job. I always try to get the axis of the bore lined up with the spindle by eye before selecting a suitable probe. The nylon ring is probably for storage, I'm in two minds whether to leave if off altogether. If your spindle speed can be reduced to under 150rpm, then under power is the best way to get the X and Y axes to the null point. A lot depends on the finish in the bore as a rough one will make the needle jump about badly and make accuracy difficult. You should not use the boring head to hold the coaxial indicator, it should be in a collet running true to the spindle.

Lucky you, to have an ideal replacement, good turning.

Good result, things sometimes work out well.

When I first looked, I mistakenly assumed that the manifold supplied twin discs. The braking would be crisper if it was ditched and a single hose used.

VFD's can be programmed for switches to work both ways, my two e-stops are in series with the normal stop button. The VFD is set for normally on, and to stop when the circuit is broken so all three switches have to be set at normally on for the motor to work. I have used two e-stop switches as they are much more prominant than the stop switch and also latch off. One is on a mag base and extension cable so it can be set in a position suitable for the particular work setup.

Edited By old mart on 27/08/2023 19:00:13

If you are going to have a go at modifying the 40, check its hardness first, and consider the relative lengths, the bore size also the drawbar thread change to 7/16 UNF.

I think you should select the sizes that would be most useful and keep them, sell the rest.

The rigidity and mass increase would make for a slight improvement when using the larger tooling.