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Member postings for John Haine

Here is a list of all the postings John Haine has made in our forums. Click on a thread name to jump to the thread.

Thread: Plaque material
24/05/2012 09:38:31

I have (perhaps unwisely) agreed to make an engraved plaque for a tree planted to celebrate the Jubilee. Obviously this will spend its time outdoors, any suggestions for material please? My initial thought is to use ali as I have some 10 mm plate to hand, with a mounting post of stainless steel tube, with stainless fixings. Site is well inland and rural so salt and pollution level is low. Will engrave on my CNC mill and if possible do an intaglio job with a black wax or resin in-fill. If possible will also use some kind of passivating coat or laquer on exposed metal surface. If it all works at a later date I might do a brass version but that sounds pricey! Questions:

  • Any reason why ali should not be used? Will it just corrode too quickly (especially with stainless fixings)?
  • Could anyone recommend a protective coating?
  • Is there a source for some kind of engraving wax or resin (I know I can get black epoxy from Maplins, and one can even use Araldite mixed with lamp-black!)?

Any suggestions or ideas gratefully received!

Thanks, John.

Thread: Open Source models
14/05/2012 09:49:31
I think the point is to provide the website (modelforge.org?) and let anyone create a new project on it. Why restrict it? It would be a good idea to post some starter projects such as toolmakers clamps etc but the whole idea is to allow designs to evolve and provide an effective way for people to find, correct, and share errors (a/k/a "bugs"). The last thing we need is a committee deciding what should be available, though you do need a light touch moderator.
12/05/2012 14:48:30

Well, being open-source anyone can put forward a model, we don't have to choose! Lots of good suggestions above to get things started.

The other important thing is the copyright licence under which the design is published. This sounds boring but is vital. There are several models from open-source software, I'll do some digging around and suggest something if you like?

John.

Thread: Not fit for purpose
12/05/2012 07:34:03

Here is an idea - Open Source Drawings. Some of the best software around now is Open Source which anyone can download, use, modify, and (subject sometimes to conditions) re-distribute.

There are some very good freedrawing packages around - e.g. SolidEdge. Anyone can download these and use them for non-commercial purposes, and anyway quite a few MEs now have CAD.

So, if drawings were made available on-line in suitable format, then people finding errors could modify the drawings, improve them in other ways, submit them back with the changes to be incorporated in the orginal, and/or re-distribute them. There could be micro-businesses for those with CNC machines to make tricky or tedious components to order using CAM to generate Gcode from the drawing files (think, castings).

All this is possible now, ME/MEW could facilitate this. Of course it might threaten part of their business, but as the saying goes, if you don't come to the banquet as a guest you are likely to be there as the meat. How about it, Dave?

Thread: Surface table alternative?
10/05/2012 09:35:34
6mm float glass is as flat as you can easily get, cheap and easily available. It does get scratched after a while and will need replacing.
Thread: AC motor speed controler
06/05/2012 09:04:35
Will not work on an induction motor! Designed for series wound motors. Avoid I suggest.
Thread: hi all whats the best method
27/04/2012 20:51:10

Toolmakers clamps will be just fine. I use them all the time on an angle plate on my VMB to secure lumps for milling. Latest was 1 inch thick CI block to square up the ends.

Thread: Meehanite Size ?
24/04/2012 12:50:05
I have used the continuous cast bar from CES and found no trace of hard scale, a delight to machine. Remember that "square" bar has rounded corners though. Can't comment on accuracy but I think they specify a tolerance. Also can supply sawn lumps that of course have sharp corners, but not very square.
Thread: magnetic base's
22/04/2012 13:05:29
CES sell squares and blocks too. But bms would work fine too if you don't require absolute maximum holding.
Thread: Vertical slide from India
18/04/2012 08:31:54

Sent you PM.

Thread: Myford T Slot size and suitable cutter
17/04/2012 22:16:13

http://www.rcgroups.com/forums/showthread.php?t=610014

60 seconds with google...

Thread: Vibration Ramping
17/04/2012 22:09:05

I've never had a cutter slip in an R8 collet, even the largest ones with aggressive cutting, so I'm surprised that you have this problem. It is the cutter slipping and not the vertical feed? How are you applying the latter? Does the cutter fit the collet properly? - it should be a light interference fit when you slide it in before clamping.

I would be inclined to clamp the plate flat on the table for thinning it, on a piece of thin card or thick paper. You will have to demount it and clamp it again - I always use a bit of MDF for drilling flat plates, better support, clamp the plate flat on the MDF on the table, drill through into the MDF..

Is the cutting speed right? Carbide tools should run quite fast I think.

Thread: Which Universities do people recommend for Mechanical Engineering?
10/04/2012 08:44:00
Leeds, Birmingham, Cambridge.
Thread: Lead screw nuts
09/04/2012 11:01:59

You could look at this thread...

http://www.practicalmachinist.com/vb/general-archive/casting-leadscrew-nut-91107/

Thread: which adhesive for cork?
08/04/2012 08:44:24
Cork tile adhesive?
Thread: Clarke CL250J motor controllor
07/04/2012 17:51:06
Excellent speed controls for high voltage dc motors like these are available from kb electronics - look em up. There are a couple of UK stockists. Much better than the original **** they seem to fit on these machines.
Thread: Linear division in early 20th century
03/04/2012 22:13:52

My point was that by the early 20th century these problems must have been substantially solved. Lathes had accurate leadscrews, people were making IC engines, diffraction gratings were being ruled etc. So I wasn't quite sure why the question was asked. The earlier history is interesting though, a project to reproduce as a "model" Maudslay's screw generating machine would be an interesting project to prove that he could have done it. Rather like the Science Museum making Babbage's Analytical Engine to show that it was feasible, or the group recreating Harrison's RAS Regulator, or the re-creation of "Rocket".

03/04/2012 13:05:07
Why is everyone talking about the early 19th century when the question was about the early 20th century?
Thread: A useful Stirling engine.
02/04/2012 16:16:37
My HTC charger is rated 5v 1amp which seems about average for mobile chargers for lithium ion batteries. So you'll need about 10w of mechanical power with a 50% efficient generator.
Thread: Cycloidal cutters
27/03/2012 09:01:44

The article I referred to is at

http://www.csparks.com/watchmaking/CycloidalGears/RichardThoen.xhtml

It is actually very hard if not impossible to make cycloidal gears exactly so they are always approximated by straight lines and circular arcs. I haven't seen any information on what errors this approximation introduces, I don't know if anything has been done. Involute gears however can be generated exactly using a hob. The article above suggests that actual production errors in cycloidal gears are quite large. The main reason usually given for using cycloidal gears in clocks is that they give lower friction in high-ratio step-up trains because their "action is before the line of centres". Thoen suggests that this is wrong, and that in practical production involute gears are (a) easier to make with smaller errors and (b) tolerate much larger errors (for example the wheels being too far apart) much better. I understand that one UK manufacturer of high grade clocks uses involute gearing. Of course, nowadays it doesn't really matter!

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