Member postings for jaCK Hobson

What metal are you melting? You can melt iron with propane and air furnace.

I spent over 6 hours walking round without stopping. The model engineer exhibition was much better than the 2 I have been to previously - more models and better atmosphere. Brooklands museum was fantastic. All together a much better venue. I enjoyed the treasure hunt. Well done.

On the down side : took a long time to and from 'park and ride' but next time I will be expecting it; very (very) disappointing trade stands which was 70% of the motivation for going (however I still spent £40 on half price angle grinder consumables); very disappointing bacon and sausage bap but probably still better than racecourse refreshments.

I suspect that the place couldn't accommodate many more trade stands?

Fitted a new wing to my van. Needs a few more bits tacking on before its finished:

I guess I was thinking of the throw-away hardpoints. Circular saw blades are thick as well and should be good for springs. TCT blades may be a gamble.

Beware some sources of second hand metal - it can have fatigue cracks that you can't see. Back of an old hand saw should be completely safe though.

It depends on the specific application but O1 (sometimes listed as ground flat stock or gauge plate) may well be perfectly suitable and you can get it all sorts of places in small amounts. 2mm would be quite a thick saw?

I've got some CS70 if you can't find anything else. You usually have to buy that in very large quantities.

To add more noise. I just use my phone as a wireless access point, or directly for internet radio. I usually forget to put the radio on.

To do the best heat treat you really need to be sure of the metal.

Ground flat stock is most commonly 01 and is a good blade material. You can't do better than follow the suppliers instructions for temperatures. You can, however, refine the grain, which is not often in the instructions and can significantly improve toughness.

If you can't find instructions, try this:

Heat to 870C and and cool in still air

Heat to 830C and cool in blown air.

Heat to 800C and cool in blown air.

Heat to 800C and quench in oil - any oil, veg oil, engine oil.

If you have tight temperature control at those high heats then you can soak for a while quite safely. I don't think you need to for a blade, but 5 or 10 mins should do it. The first heat is more important to soak than the last.

If you don't have good temp control, then don't soak at high temp for long - just get it to temp.

Temper at 220C for one hour - a bit longer if a really thick blade. Some O1 guides suggest a toughness peak at this temp - going a little higher can reduce toughness.

Heat treat may result in breakage.

8" long, 1/2" thick is outside my experience and longer soak times at high temp, and higher temper may be more appropriate - find the instructions!

If the 'tool steel' is not O1 then it may be air hardening and oil quench could be too risky. If in doubt, and you want to be safe, first 'quench' in air and see if a file skates on the surface... if not then quench in oil. Repeating heat treat is OK, quenching too slowly does no harm - it just doesn't get hard. Quenching too fast will result in breakage.

Edited By jaCK Hobson on 31/05/2016 08:35:44

Edited By jaCK Hobson on 31/05/2016 08:39:13

Edited By jaCK Hobson on 31/05/2016 08:43:36

A possible explanation: Circular error is not linear with pendulum amplitude. For small swing there is very little error - oil may make the swing slightly larger but additional error is still insignificant - however, the oil may influence other mechanisims in the clock, some of which make it faster. For large swing, the oil may give the same % change in swing but the % increase in circular error is much greater and this becomes the main source of change in behavior, swamping the other effects of oil.

Edited By jaCK Hobson on 03/05/2016 08:18:06

Edited By jaCK Hobson on 03/05/2016 08:18:51

I finally tried mine on 12v lead acid. Results were a bit dissapointing. It can get a 3mm screwdriver just red hot but I don't think it is really hot enough for an ideal heat treat. It gets stuck at that heat as, depending on the steel, it starts to lose mangentic properties and the heating becomes less efficient.

My bigger one should be better... if I can get a 40V DC supply...

Nice tiles!

I put the towel rail up at the weekend:

Edited By jaCK Hobson on 28/04/2016 08:17:08

There are videos of clock B about

http://www.guinnessworldrecords.com/news/2015/4/video-how-%E2%80%9Cperfect-clock%E2%80%9D-redefines-timekeeping-history-300-years-on-377653

I guess copyright could be a little complicated. At the moment it is still inside the Greenwich Observatory workshop and only viewable through a window. Not sure if pictures are allowed in the museum. And the clock is only on-loan.

It's a discussion forum open to the internet. I'd have though free discussion would want to be encouraged. Some of the most interesting discussions wander away from the original topic. 

My mind has been changed by Michael and John and thank them for it and I'd like more. I don't think the OP is overly precious about keeping this 'his thread'. I know there have been threads where we've had to tread carefully in the past, but personally I like forums that encourage freedom of discussion. However, I'd be disappointed if this thread turns into a discussion about forum ethics and etiquette - and I'd be responsible I think the intention of the most knowledgeable people here is to point out that remontoires are an advanced device and not usually part of a basic design, but a similar concept may have a place for winding the weight as a space saving device.

btw: I do not include myself in the  "most knowledgeable" group but I do hold the above opinion. 

Edited By jaCK Hobson on 21/04/2016 08:16:51

Even earlier were 1/2" which is even harder to find but std drill chuck will fit.

Sherline do chucks in all these sizes and are good quality for the money.

http://millhillsupplies.co.uk/sherline/sherline-chucks/

Edited By jaCK Hobson on 20/04/2016 17:06:49

I think at one time it was proposed to define the meter as the length of a pendulum with a half period of one second. That didn't stick but it isn't far off.

Vic - I really like that! There seem there might be a few extra features that I don't appreciate?

I was wrong. But, the motor driven weight could be a nice simple solution for Jame's clock.

Can the motor driving the brass weight be considered a form of remontoire or are there some conditions it doesn't meet in order to be considered one? e.g. does it have to be supplying power closer to the escapement?

Edited By jaCK Hobson on 18/04/2016 13:56:08

I think my dog is clever, but only uses her brain if the motivation is right. The most reliable motivation is food.

Last week she had a vet collar on which extended past the end of her nose. It took her a long time to work out how to jump up on the sofa but didn't take her long to work out how to eat. Very clever at accessing food - and will wait patiently and nonchalantly until no one is looking. On the other hand, acts very stupid and unable to understand simple commands if they reduce her chances of accessing food.

I seem to remember the electric drive to the remontoire was really simple - no clever escapement. Are you looking at the right thing - I think the remontoire weight is brass lump at bottom left of picture.

I got one and blew it up in minutes. I wasn't very careful.I was hoping it would be good for horology. I got another but have not tried it yet. I can at least vouch for reasonable delivery times

I notice you can buy induction heaters intended to loosen rusty nuts. Probably similar electronics inside.

I also got a much bigger one for £20 but I need to rig up a high current 40V supply... I was thinking of using my welder and rectifying the output but not sure what capacitors to use.

Edited By jaCK Hobson on 17/04/2016 15:17:19

And I didn't mean to discourage discussion - I hate that when people tell me to shut up.

I now get the point that a simple electric driven remontoire may be a ... simple... solution. A great example is that used on Brugess Clock B http://www.frodsham.com/burgess-regulator/. Well worth considering.

However, the first thing that came to mind was something like I saw at the British Museum which looks a bit more fiddly:

http://www.britishmuseum.org/research/collection_online/collection_object_details/collection_image_gallery.aspx?partid=1&assetid=309818001&objectid=55352