Member postings for Massimo Dalmonte

Rohm Supra chucks come in several "flavours" (L, S,...) with different concentricities:

**LINK**

Top of Rohm line is the Spiro series (0,05 mm):

**LINK**

while Albrecht is given for 0.04 mm.

Massimo

Hi Mark,

nice step by step report, I think this is the best solution for me too; I initially thought I would have used 3 taller cylindrical magnets, but your approach has "more magnet" and is to be preferred.

Hi,

I bought one of these a few years ago, was very cheap then, about 10 euros, complete with sheath and spare scriber:

it has a couple of advantages versus modified regular verniers, the roller and adjustable scriber "height".

Massimo

Hi Bill,

yes, this would be the logical approach, but I live in Italy and the round trip must be costly, it's a rather heavy item (and probably I would have to pay the customs too on the return leg), that's why I hoped about a local solution.

I'll try to enquire with Eclipse anyway, to get an idea, thanks.

Massimo

An update: I went to an old school car electrician, a gent in his eighties, who owned an antique remagnetizing contraption and treated my block with it for a few minutes.

A nice guy, did it for free, but alas I didn't notice improvements; didn't have the courage to tell him...

On the other hand, I read on the net:

"don't bother to buy any of the small homemade magnet chargers - they will not saturate an AlNiCo magnet."

(as I suspected).

Mark, I think we have the same:

the magnet in the "on" position:

looking with a gadget which should give an idea of the magnetic field lines, we see that these do not look very "healthy":

for a comparison, this is a stack of magnet as found in hard disks

the idea of the neodimium magnets stack is good, but I'm afraid that if there is not a complete path of high magnetic permeability material, with the minimum of air gap, but some brass or aluminum, the magnetic effect could be strongly reduced ( anyway I could be wrong Dave, magnets are almost black magic for me ).

Massimo

A "paint" made with jeweller's rouge and water, applied with a brush, works too.

Best regards,

Massimo

Good afternoon everybody,

I recently bought an old V block, the magnet was stuck and I managed to have it move again by soaking it in ATF fluid and then hitting the magnet with a wooden dowel alternatively from both sides.

Doing this, the major part of it was always in its cavity, protruding about 1.5 cm over the total of 10.

I don't know if this was enough to loose magnetism, anyway now it works, but, once set on the milling machine table, I can move it rather easily with my hand.

Is it possible to restore the original magnetism and could you tell me which kind of firm I should turn to?

Thanks,

Massimo

Yes, I see that the smaller UPT motor pulley seems rather bigger than the one on my lathe ( 1-3/4" against 23 mm), giving an advantage in the resultant grip.

Apart using a slightly bigger diameter belt, another improvement could be using a leather one, previously soaked in neatsfoot oil, which was the best material available, according to Tubal Cain, if I correctly remember .

To further reduce the weight, you can remove the headstock too (that' s what I did last time I moved it, though, as said, it is very manageable anyway).

On reinstalling it, the headstock locates again as precisely as before, thanks to the vee bedways.

Massimo

Thanks everybody for the replies; I'll follow your advice, belt dressing spray and smooth round belt are on the way and I'll check the pulley profile (which looks homemade) again.
Actually, the previous belt was 5mm, this one is 4mm and this could explain part of the problem, beside the textured surface and harder material.
About the tension it should be almost right, though the fact that there are two belts running at 90 degrees to a pivoting countershaft complicates things a bit, as tightening one can slacken the other or make the motor belt touch the countershaft structure.
Anyway nothing is impossible, I'll have to make small changes in belts length and countershaft position at a time until right, no improvement in any area is too small to be considered.
Thanks again everybody,
Massimo

Good afternoon everybody,
I own a watchmaker's lathe I seldom use, it was first fitted with a smooth red round (polyurethane?) belt and, from what I remember, I didn't have problem with slippage.
Having to use it again, I found that, with the years, the belts had hardened and they almost immediately broke .
I bought some of the textured green belting available from various sources, but, though the hot melt joints are easier and nicer than the other type, the belt slips soon, offering almost no traction.
I first put this to the profile of the driving pulley (almost a perfect half round) and material (brass), so I tried to modify it to straight converging flanks, in order to have the belt to "wedge" in and improve traction.
Alas nothing changed, trying by hand, the feel of the belt on the pulley is almost as if there was liquid soap on it, probably using steel or aluminum would make little difference.
An idea I had, was coating the throat of the pulley with epoxy and sprinkle some sand over it, but perhaps you can give me some advice about how to overcome the problem with some specific kind of belting material.
Thanks,
Massimo

Edited By Massimo Dalmonte on 02/06/2021 14:18:56

Edited By Massimo Dalmonte on 02/06/2021 14:19:36

I remember reading somewhere that, in a factory, big castings were stress relieved by suspending them and having apprentices hit them with hammers (surely the hammers were small and used in way not to chip the castings); it's on a larger scale what is recommended when stick welding cast iron to avoid cracking the weld.
Massimo

Thanks everybody,
so the plates I was referring to are dyed anodized aluminum (always thought of color anodizing as covering the whole object and not only some parts of it...); it almost seem I could replicate this at home, using the same photoresist film used for pcb, though there is surely a learning curve to get decent results.

Massimo

Good afternoon ,
I always wondered how the black and "white" aluminum plates found on various appliances (specs on electric motors, speed charts on lathes, etc) are manufactured.
I think it involves a silkscreening process, but I don't know how the black part is obtained (it' doesn't look to be a paint, more some black oxide, as it is tightly adhering to the underlying metal, with no discernable thickness).
If somebody knows more about the process, I would be happy to learn something new.

Massimo

Edited By Massimo Dalmonte on 10/12/2019 11:41:42

Hi Robert G8RPI,

soon after reading your post, I bought 6 (4 of them will be used to make levelling feet for my milling machine) .

Cheers,

Massimo

If you happen to be traveling in northern France or Belgium, look for "Blanc de boeuf" (it is used to fry Pommes frites), inexpensive (3.99 Eur \1 kg).

Massimo

Edited By Massimo Dalmonte on 06/06/2019 16:41:43

Ten years ago, though I didn't have a specific need, I liked very much the idea of the J.A.Radford headstock indexing attachment and thought of putting a stepper motor on its worm shaft to spin it.

The stepper would be driven using an old laptop via the parallel port () and I made a small Visual Basic program, using a DLL (IOPort.dll, I think to recall) to output the signals ( these had to be "strengthened" in some way before sending them to the motor, naturally).

Here is an example of how it worked: the three input data are:

- motor steps per revolution: 200

- bullwheel teeth: 65 (I own an ML10)

- holes to be drilled\teeth to be cut (9 in this case)

Dividing 13000 steps by 9, gives 1444.4 period, so each position will be 1444 steps apart from the previous one, and we will have to spread 4 "orphan" steps on the whole revolution (this is done 3 times, on holes\teeth 3,5 and 7, the 4th step is not added, though now I see that it could be added to the first or the last step...).

Hitting the button started the sequence, the 8 outputs to the Data pins of the port were monitored in the Out frame, the DLL provided a choice of the kind of sequence used to drive the motor and it was possible to change the interval between one sequence and the next, to adapt it to the stepper.

As with a lot of my projects, I didn't proceed further with the hardware part, due to lack of time, but who knows... (today I think the motor command part is even simpler)

Massimo

Edited By Massimo Dalmonte on 31/05/2019 07:35:33

Hi,

as others do, I etch pcb boards putting them vertically in a tall and narrow Tupperware container, along with an aquarium heather and a small flexible PVC tube (drilled with a few 1mm holes) coming from an aquarium pump on the bottom, works well.

Massimo

Edited By Massimo Dalmonte on 09/04/2019 17:49:58

Good evening,
I bought a Myford leadscrew handwheel to mount it as an apron handwheel on my ML10, instead of the stock ball handle.
The leadscrew handwheel has an index ring cast on its periphery that I wanted to remove.
I took one of these:

the name is something like "MGEHR1010-2 Grooving Turning Tool Holder" (there are several sellers, I chose the cheapest one with 10 inserts, around 7 GBP including shipping costs):

I set the tool in the front toolpost right with a try square and proceeded in lowest backgear (48 rpm) as the cdiameter was 86mm: the operation completed perfectly, with the proverbial "sizzling bacon" sound, and in the end I could remove the cast iron ring.

Admittedly Myford cast iron seems a nice material to machine, but I never had the impression to reach the limits of safe operation and the 2mm insert finished in as good as new conditions, though, when the ring was almost severed, the cut was interrupted each time it met the spokes of the handwheel.

Cheers,

Massimo