Member postings for Gordon W

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

Thread: Tongue in cheek
25/01/2010 15:24:34
I always was told it was the width of old wagon track near the works. Anyway, track gauge varies depending on curve rad. etc.
Thread: Solid Alcohol
25/01/2010 11:58:41
I use lots of firelighters, There are many different types, from sawdust soaked in old wax to very clean burning dry white blocks sim. to camping fuel. Would suggest ones advertised as suitable for barbies would be best, but can't tell until yuove bought them. Brands seem to change the formula also.
Thread: Grub screw has turned to cheese!
21/01/2010 10:42:13
The old agri screws with sq. heads - brill. spanner doesn't slip on them. In the olden days, when I was young, the socket head screw makers published loads of data, one book had several pages of info. showing transmitted torque for different angular disposition of grub screws round the shaft, the closer together the better! One opp. the other in some cases less than one screw. Two in line best (for power transmission).
 A bit OT ,I can remember one maker, Unbrako?, had a tool for sale which peened the sides of the head counter bore into the grooves on the head, so locking the bolt. Can't find the ref. now, anyone remember these?
Thread: Brass Shell Case
16/01/2010 10:46:00
Acronyms are initial word letters that make a pronouncable word, eg. BSW not, BSA (beeza) is. Thread interesting for me, recently tried similar with 4" dia S/S tube ,flue pipe, unknown spec., made a steady from black bar, brass pads etc. but it would not cut. Used angle grinder with fine disc, cleaned up with stone disc, rechucked and marked line, recut to line, good enough for job, IMHO. Still got the steady as well.
Thread: Hot air and stirling engines
12/01/2010 09:47:37
Thanks for all the info. Mark & Ian, I've seen photos of the Philps motor ,looks very neat. I think the penny has finaly dropped re pressure pumps, the motor driven pump only needs to make up for leakage once engine up to pressure ? I decided to build a bigger motor because I'm not very good at small things, there is plenty of room to add pumps, air and water,to try different ideas. The snow has started to melt so can get on and order matl. etc.
Thread: What type of "plastic" rod machines best?
11/01/2010 10:17:43
If we want to use any matl. of unknown provenance it can be tested first. weigh, and measure the sample, put it in water,oil, brake fluid, or whatever, leave for some time, then remeasure. I know this is not to industry standards but we are not industry. This is especially useful for plastics, esp. "O" rings.
Thread: Hot air and stirling engines
11/01/2010 09:58:27
Snow here, N Scotland heavy, just now have reached a dizzy 0 deg cent. Havn't been out since Xmas which is probably why my brain is going overtime. Trouble is with so much to do , like digging snow out to find the firewood, shoveling snow of roof to stop collapse etc I've not time or energy to do much in w/shop. It's worth googling Manson to have a look at it.
10/01/2010 13:42:10
I'm thinking (only thinking) along the lines that making a bigger temp differance will have more effect than pressurisation, if the cold end could be below 0deg cen.? How about pumping ammonia as a coolant. Have you seen the Manson engine? This has a valve arrangment to let in a fresh charge of air each stroke, I've got one half made.
Thread: What type of "plastic" rod machines best?
09/01/2010 15:36:07
Nylon absorbs water and swells, don't know about Delrin.  Knowing the bush will swell by x amount, why not allow for that in the M/Cing? My steering bushes are plastic and not tight, don't know what they are made of. Which is my point, how do we, as small scale buyers , have any real idea what we are getting ? I asked same question about HSS some time ago.
Thread: Workshop Heating
09/01/2010 12:17:23
That stirling board sounds dear to me, where are you? Forgot to mention the biggest heat saver ( in my shack) Double glazing, this is all second hand and cheap or free. check auction ,salvage yards, double glazing firms, mates who are upgrading etc. You can cut the plastic frames easily, and fit to hole in wall with timber packing and lots of mastic.( like the profesionals) or just use the glass and make your own frames.
Thread: Hot air and stirling engines
09/01/2010 11:58:26
Thanks for all the info. I know the gas laws etc. , wether I understand them is a different matter. My thinking is this:- ( I know it's all been done befor) Heat the air (working fluid) air expands, pushs working piston out, air is cooled, contracts, flywheel & atms.pressure moves piston in etc. Comp. ratio very low so low power.Some motors fitted with snifter valves just to try and maintain ambient pressure. To improve power pressurise with pump of some sort as you are doing? Does the power to drive pump not aproach , or exceed power gain? So a bigger Temp. difference ( degs. Absolute) would have more effect. Cool the pump and air? I'm thinking along the lines of modern matls. should make some of this possible. I apologise to all you experts if I'm rambling, but just trying to get it all strait in my head. Will try to order book mentioned from Lib. when we return to normal.
Thread: Workshop Heating
08/01/2010 17:34:41
Wood burners are great and cheap to  run on scraps, but not worth bothering unless you are going to be in all day. I used to make them, for a workshop get a suitable lump of box section, maybe 8" or 12" sq. and 10 mm plate and 5" dia. pipe for flue, weld bolt or rivet together. Mach. Mart sell quite cheap ones. Cladding- see whats cheapest at builders yard, I used stirling board, do you have auctions near you, often get damaged stuff like boards. A good 2 coats of the cheapest white emulsion works wonders.Best way to stop condensation is ventilation, wood burner helps with that. I don't like using plastic etc. as a cover, prefer old bed sheet, curtain etc. so it can breath.
Thread: Hot air and stirling engines
08/01/2010 14:45:17
I've been re-reading History of HotAir Engines, R. Sier. What I'm looking for are temperatures. There are some actual tests of engines and even one or two Indicator diagrams but no details on temps. What I would like to know are Hot end temp, cold end temp, and temp. at the working cylinder. All these for old Stirling type engines. I do realise that there will be huge variations but figures for one eng. would be interesting. Has anyone any ideas? Has any one actually measured the temps?
Thread: Workshop Heating
08/01/2010 09:52:08
My w/shop is 8' x 16' made from 1/2" ply with polystyrene 40mm in roof, there is 2ft of snow on roof. Only heating is small fan heater and its not too bad, dont have much trouble with rusting, tools are well oiled & used frequently. Davids lights reminds me, I used to use "pig lights" these are/ were used as creep heaters  for piglets. Had one in the bathroom, very effective for heat and light . Don't know if still available but will find out when I can get to civilisation. Have tried low wattage background heating, not effective unless on all the time and this costs a fortune.
Thread: Lathe, lowest speed?
07/01/2010 09:51:10
I've just fitted a bigger pulley to my small lathe. Bored out inside to fit over existing pulley, scewed flat plate to outside of new pulley, tapped 4 holes in existing pulley (just missed the second V), this gives me about 60 rpm. Need a longer belt, and end cover has to open, or modify to suit. The new big pulley has a flat top, not Veed, and works OK. I use a mandrel handle for screwing, for short threads, this works fine. Big pulley can even be made from good plywood.
Thread: Hot air and stirling engines
05/01/2010 16:48:05
Hi Iansc, yes but, I think it's more complex, I/C  real cr varies with valve overlap, cyl. filling etc, not just the mechanical ratio, also turbine cr, and the rotary eng. which can't be made with a high mech. cr. Apologies for rambling, getting cabin fever, been snowed in since xmas. Moorfield & winstanley, updated 1947, reprinted 1958, can't believe I passed an exam on that. Trouble is not one bit of it has been any use, except for model making ideas. Having not much else to do I'm trying to re-read it, and might invent the steam engine.
05/01/2010 10:43:26
I've been re-reading my old tech school Moor & Winstanley (?) Heat Engines. Mostly steam & valve gear etc. Published 1958 ! no wonder I know nothing. No ment. of hot air, but does seem to show that all combustion engine power is directly proportional to the compresion ratio. How the comp. ratio of a hot air motor is calculated I 'm not sure, but the dead space must be relevant.Also seems likely that a leak in displacer will have less effect at higher speeds? Will now re-read book. Apologies about my earlier remarks about Ross yokes and friction, getting confused over ross yoke, scotch yokes, scotch links etc.
04/01/2010 11:30:33
The engine I'm making is loosley based on a description in old mag. Amateur Work. I'm just reading some of the old instructions, I quote "transfer piston made from sheet iron seamed at joints, joints need not be particularly tight, and one or two small holes should be drilled in the side to prevent air pressure when heated" . I asked this question in the past , and am told it's a no no. Also the old working hot air engines had all sorts of  regenerator ideas, some of which must have been less than air tight . Any comments anyone?
Thread: Suds vs neat cutting oil
03/01/2010 15:47:27
Not very relevent but, I use soluble oil in a squeezy bottle on my old "big" drill. The oil is at least 20 yrs old ,diluted about 1 to 6 with water, it's frozen solid. Which is why I'm sitting here instead of doing something useful. PS .no bacterial action.
Thread: lathe tool advice
26/12/2009 13:47:32
Thanks for that Nigel, yes I've met the tough water pipe as well, but beeing small dia the cutting speeds could be low. New pulley just about ready to fit, should get down to 70 rpm, as low as I can easily get. HSS ,How do I know what I am buying? Prices for 1/2" sq. x3" long seem to vary from £2 to £10 ,just assume the dearest is best? For interest the old piece I ground up to do my job is marked Goodyear, I'm assuming it was a form tool for tyre moulds, but maybe not,  good steel anyway
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