Member postings for Dick H

Sometimes a photo helps, when you see the part you can start to guess as to how it was made (injection moulding ejector marks, witness lines etc..) else solubility, does it melt, feel (dry waxy?). For most of his working life my father worked with phenolic resins which used to turn up in brake pad, billiard balls, rosary beads, cutting disc for jewels and lamp capping cements amongst others. I worked with high temperature thermoplastics PEEK and PES..

Sometimes if you can describe the part you will get lucky and an internet search will give you a match and a clue what something is made of. If is a small volume part, this may also be a clue. Sometimes just a filled epoxy, well cured, will do as a substitute.

Regards,

Dick.

At risk of suggesting the blindingly obvious, try searching Harmonograph. One of the links Model Engineer 1960 vol 3087, p.300 even has plans for a pendulum version.

There is a vague reference out in the web, the blades for the Proxxon 28054 jigsaw seem to be compatible.

Maybe there are still spares:-

The bit you want, I think, is is the "Spindelplatte 2450-0203".

The machine is similar to a MD-65 and Proxxon took over making/marketing them from Unitech after 1991.

The manual and exploded diagram is here Link to Spares for SD-300,

Proxxon themselves might also have the bit Proxxon Spares. I´ve dealt with them in the past and they were quick and efficient and the bits didn´t cost an arm and a leg. Not sure if they ship to the UK.

Regards,

Dick

Not quite sure where to put this.

I have a Sieg SX2L mill. I´m in the process of adding DRO´s to the three axes. On the Z axis I have removed the vertical mm scale on the LHS of the mill to fit the DRO. The pointer for the scale is held in place by a nut and an Allen / hex screw with a cylindrical end, the sort of end that would normally sit in a groove to stop a part rotating. Does this screw have any other function than holding this little silver pointer in place? I can´t see any other function from the exploded diagram of the head. Just want to check before remove the screw and use the hole to drive the read head of the glass scale DRO.

In retrospect perhaps I should have started by fitting air springs and getting rid of the sprung counterbalance arm first.

Dick.

Not quite sure where to put this. I have a Sieg SX2L mill. I´m in the process of adding DRO´s to the three axes. On the Z axis I have removed the vertical mm scale on the LHS of the mill to fit the DRO. The pointer for the scale is held in place by a nut and an allen / hex screw with a cylindrical end, the sort of end that would normally sit in a groove to stop a part rotating. Does this screw have any other function than holding this little silver pointer in place? I can´t see any other function from the exploded diagram of the head.

In retrospect perhaps I should have started by fitting air springs and getting rid of the sprung counterbalance arm first.

Dick.

If it is indeed an NSU Quickly motor there are specialists in the net for these things. Google "nsu quickly Zündkerze" and it will throw up a Bosch spark plug.

I repaired a couple of these solar lights (not so nice as yours). I assume the battery is a rechargeable NiMH cell (~1.3v) or similar. The circuits used a yx8018 chip and a tiny inductor the size of a small resistor. as to the LED, any white LED should do.

Google "Joule Thief"..

O-Ring sealed fittings should get you down to about 10-5 torr but it won´t stay there. A lot depends on the pumping, a water jet pump is limited by the vapour pressure of water, a two stage rotary vane pump 10-3 - 10-4 torr, add a cold trap and or diffusion pump 10-6 torr and lower, then you get into the realm of turbo molecular and ion pumps.Several careers ago I ran UHV systems, on one occasion we baked the machine to get the best vacuum for a customer demonstration, upon reconnecting the ion pump the electrical feed-through shattered., 10-9 torr to atmospheric pressure in a twinkling. I could have cried..

Before you get too carried, away think about the vacuum chamber and containment if any thing goes wrong. One of the scariest chemical practicals I had to do involved producing a metal sandwich compound which involved evaporating a metal and combining is with an aromatic compound in a large glass flask in a cooling bath (Timms Synthesis) , What could possibly go wrong?.

I also ran grease free vacuum lines using a compression fitting sealing (Swaglock)on O-Rings. For what you want O-Rings (Viton) should do.. Conductors embedded in epoxy should also work.

I don´t know whether this is useful but could it have something to do with the set-up pots given that there was a bit of humidity.? (Manual for similar board)

I got one of these in kit form a few years ago just to play with (ie. not the slick SainSmart machine.). The original electronics was very probably arduino based and had the name "Woodpecker" inscribed on the PCB. The electronics were very prone to electrical interference, crashing at odd moments. In the original SainSmart lit. they add capacitors to the motor stop this, I tried this with my primitive setup and it smoked the capacitors so I moved on to attachable ferrite rings and a big diode the "wrong" way round to trap the back emf of the motor. The SainSmart box of electronics seems more stable although I did manage to wreck a MosFet controlling the motor on one.

Adding MGN type rails in addition to the rods on the x-axis makes a lot of difference to the rigidity (somewhere out there an Australian user describes his mods).

The z-axis is made from 3D printed parts but seems relatively OK. Thingiverse has recipes for improved and larger capacity mounts but a bigger spindle would bring larger loadings and strains. Where do you you stop?

I tinkered with the anti-backlash nuts on the x-axis drive in that I added screws to push off the brass to positively take up the slack rather than rely on the spring between the two brass fittings on the drive screw..

At the end of the day the 3018 is a learning tool, an engraver. What I need is a source of easy material to machine to play with and not be too upset when it lands in the bin.

No real insight except a discussion on the NAWCC where they noticed that when a weight descended to the height of the pendulum bob the weights started to swing in or out of phase with the pendulum. Shouldn´t happen if the clock is on a stable base or well fixed but even then.. Else strange, no idea, the usual cry is oil and or clean it.

Could it be something to do with the way the drive chain flows over the drive cog? Sometimes chains open a bit and distort. Perhaps your parents wound it more often and never used the last bit of the chain. Just a daft idea else I can´t see what should change.

Not quite the same...

https://www.selva.de/en/all-categories/watchmaker-tool-workshop-need/watch-repair/silversmith-anvil-short-horn-4420288

My missus drives my 1994 VW Golf and if left for a while it loses bits of the LCD display. Drying the car out (ie. a bit of time in the sun and actually driving it) bit usually restores the function. What you depict is a bit more. Put in a bag with a desicant perhaps?

It is at least 15 years old, so i hope not, else I'll have to get a flame to it. Thanks again.

Dick.

Many thanks. I couldn´t see from the exploded diagram what was going on. I´ll have another go over Christmas.

Regards,

Dick

Tried to remove the top drive pulley from the spindle on a Proxxon FF230. There is a tiny grub screw to loosen and then as far as I can see from the exploded diagram it should just pull off but doesn't. I´m very wary of using too much force and a puller is more likely to bend the aluminium pulley stack. I just wanted to tighten the screws that hold the drive to the quill but they are hidden under the pulley.. Any suggestions please.

I have a Proxxon FF230 mini (nano?) mill, Can someone please tell me how to remove the stepped pulley at the top of the spindle? There is a very small grub screw to be removed and then I assumed the pulley should be able to be pulled off. Am I missing something? Is it screwed on or has someone used a locking compound on the shaft? I don´t want to use too much umph on it.

Dick.

Same in Germany. Buy stamps, pay with a card and you can track the sender and recipient. Perfect.