Member postings for Tony Jeffree

The whole essence of the Hipp toggle isn't the mechanism itself, but what it is there for - which is to both detect the decaying swing amplitude of the pendulum and to trigger the electromagnetic impulse necessary to restore the swing amplitude, and therefore keep the swing amplitude within defined bounds. This clock uses sensors and logic to achieve the same end result, but with no mechanical interference to the pendulum - as did my own free pendulum clock, serialised in MEW last year (https://www.model-engineer.co.uk/forums/postings.asp?th=171748 ). I suspect that if Hipp had been able to use modern electronic devices in place of his toggle, he would have done so, but in his day, he had little option but to invent a mechanical solution. That being the case, describing this (and my clock for that matter) as "an Electronic Hipp Clock" seems pretty reasonable to me.

I used a second sensor in my clock - partly for that purpose and partly as a means of determining the duration of the impulse.

Very interesting. The "free machining" variant would be most welcome!

Anecdotally, Invar does seem to vary considerably from sample to sample. I came across a report somewhere back in the mists of time of a sample that had a negative expansion coefficient.

And yes, threading an Invar rod can be a less than satisfying activity!

Absolutely.

...all of which is consistent with what I wrote.

My view is that with a VFD you really do get the best of both worlds. Use the VFD to change speeds where that is convenient/useful/appropriate; where it isn't, you still have the option of running the motor at "normal" speed (where it operates at max power and max torque) and increasing the available torque by using the pulleys/gears.

As John's link above shows, a VFD/3-phase motor setup will generate broadly constant torque below its "normal" operating frequency (60Hz in the example shown) and broadly constant power above that frequency. If you are wanting to maximise the amount of metal that you can remove, then you need to maximise power, so you want to be operating in the middle/right hand half of that curve, but for some other operations (as John observes) like tapping where torque is needed but relatively little power, then operating in the left half is just fine, and particularly for operations such as tapping, the speed control is very helpful indeed. I often tap at low speed under power in my ML-7 - haven't yet broken a tap that way.

Having had one of the first Newton Tesla kits fitted to my lathe for a good many years now, what I find in practice is that the variable speed allows me to use the middle speed range of the lathe for most of the work that I do, and that it is relatively rare that I need to shift pulleys up or doen (or engage back gear, for that matter).

Fitting a VFD to an existing 3-phase setup is significantly cheaper than other options for providing a 3-phase supply from single phase, so even if you plan not to use the variable speed option (always run at 50 Hz and change speeds via the pulleys) then it is still a no brainer if your mains supply is single phase only.

I agree. The only mistake I made was going for a 1/2HP motor instead of a bigger one, but hey ho.

It's a long time since I used it, but the last PCB layout package I used was "Easy-PC". I seem to remember that it was (as the name implies) fairly easy to use.

Hi Dave

The code is actually pretty trivial, especially when you see it in the "block code" format. It is printed in part 3 of the series (just out) but unfortunately it is a bit of an eye chart, so I have uploaded Photo 21 and Photo 27 (the two block code programmes from the article) to one of my albums so people can access it more easily. Also inserted below.

In principle you could indeed extend the code to allow a digital display and I did consider doing just that, but as you rightly observe, the issue isn't displaying the current time, it is setting the initial time, which takes much more effort. Not clear to me whether this would tax the capacity (memory-wise) of the micro:bit but it could easily be off-loaded to a second processor if need be.

Edited By Tony Jeffree on 19/07/2022 17:54:55

That's a dead giveaway - if it was from a credible source the suffix would be .gov

We've had a few of these - they go straight in the bit bucket.

Nope.

It's well tough enough for that job. In fact, there were some pics of printed change gears posted the other day that seem to work.

Edited By Tony Jeffree on 11/01/2022 16:26:55

On the Facebook ML7 group Addison Gray has posted a link to Thingiverse for a ML7 bull-wheel spindle lock design, in two forms:

Here

and in wrench form:

Here

Haven't printed these ones out yet, will do so this afternoon, but thought it may be of interest. I have printed out a similar design posted by Addison in the FB group which works very well.

.

Edited By Tony Jeffree on 10/01/2022 21:33:00

True.

Indeed. The most practical combination would probably be router and laser.

Thanks for the link Nigel - an interesting review. I would agree that ideally, you would go for 3 separate machines, but there are circumstances where that isn't a practical solution, so as always it is horses for courses. The price tag is a tad on the high side I must admit!

Tony J.

I have an ender 3 thanks. I was looking for feedback from someone that had actually used one.

I'm intrigued by the Snapmaker concept - 3 tools in one, 3D printer, laser cutter/engraver and CNC router in a single package with interchangable heads. Especially intrigued as they are about to release a more powerful laser module - 10W as opposed to the standard 1.6W, and claim it is good for cutting up to 8mm in some materials.

So, has anyone had any experience of these machines?