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Member postings for macmarch

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

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Thread: VFD Drives
18/03/2011 09:14:02
Thanks for all the replies. I have now conducted tests and found the problem not so bad as first experienced.
 
Medium wave. A definite no no even 50ft away. ( I like Gold)
VHF. I moved the radio away, took off the wire extra aerial wire. At 8 ft from the lathe there is only a hint of noise.
DAB. Oofficially, according to the BBC, here in the fens we should not be able to receive at all. I get a very strong signal by attaching the earial wire to the screen of the satellite cable. My DAB indoors is fine but in the workshop no way.
Oddly enough using my mobile standing at the lathe has no effect whatsoever!!!!
I'll put the mains and motor cables through separate flexible metal conduit and a box tunnel over the inverter and see what happens.
 
I'll report back in a few days.
 
cheers all
 
Ray

Edited By macmarch on 18/03/2011 09:16:21

17/03/2011 19:43:12
Thank you Kwil,
 
I'll run the motor leads in conduit. I'l have to leave the last 2 inches and cover this with a floating bit of tube and connect by use of clamps and heavy earth wire . The control cable has NO screen at all, but as its only low voltage and is 4 switches and 1 pot it shouldn't be a problem.
As the inverter has the mains and motor earths I'll ;ink the conduit to the lathe and on to the supply earth.
You didn't mention the inverter. I'll assume that a cover in the form of a vertical channel would be better than nought.
 
cheers for the info,
 
ray
17/03/2011 18:57:28
Not sure which forum to put this on.
I am enjoying my newly fitted FVD drive. The thing is that I have the dreaded RFI problem. Searching t'internet has resulted in so much conflicting information that I now turn to those who have been there/done it.
From what I can glean, it seems that the cable from vfd to motor is the main culprit. Shielding this should reduce the problem. Can anyone advise :-
 
Metal Conduit.
Earth one end or both.
Link that earth back to the common Inverter earth or direct to supply earth.
Metal cover over inverter,  (with provision for air to enable the fan to cool correctly), again earthed to supply.
Fit new earth from lathe to supply.
 
I need to sort something out the intreference is MW, FM and DAB to at least 20 feet from the workshop.
 
ray
 
 

Edited By macmarch on 17/03/2011 18:58:31

Thread: Different Steels
28/01/2011 20:45:04
This site is useful without being too technical.
 
 
Ray

Edited By macmarch on 28/01/2011 20:45:24

28/01/2011 18:20:19
The main thing to remember is that 070M20 (EN3A) is weldable. EN1A can be but it is likely to crack. EN1A is sometimes supplied as EN1AP, this has lead added to enable easy machining on auto's and cnc lathes. EN3A is also better for lightly stressed parts. 080A15 is best regarded as the equivalent to EN32, a case hardenable steel whereas 080M40 is about EN8, a heat treatable steel.
 
cheers Ray
Thread: steam turbine and generator
20/01/2011 21:43:10
Just remembered, Shrecklin developed them. Like steam turbines they gulp fuel as fast as it can be poured in.
ray
20/01/2011 21:41:03
As far as the bearings are concerned, perhaps someone here is familiar with the turbines used in model jets. I forget the manufactures name but the shaft spins in excess of 300,000 rpm.
ray
Thread: Mandrel Handles
12/01/2011 17:13:16
Oops clicked to quick.
12/01/2011 17:12:06
Nobby, This is how I do my threading on spacers on my BH600.  I only have 1 thread for the undercut and often 2 threads for the job.  With female threads it would a braver man than I am. Even with inverter drive there is only 20 thou to play with.  I can't rely on the drive to stop in 1/2 a turn. 
In my version the handle fits into slots around the circumference.  Down the centre there is an adjustable rod which I can use as a backstop.
 
If anyone is interested I'll put up pics in Hints and tips.
 
Ray
 
12/01/2011 17:12:03
Nobby, This is how I do my threading on spacers on my BH600.  I only have 1 thread for the undercut and often 2 threads for the job.  With female threads it would a braver man than I am. Even with inverter drive there is only 20 thou to play with.  I can't rely on the drive to stop in 1/2 a turn. 
In my version the handle fits into slots around the circumference.  Down the centre there is an adjustable rod which I can use as a backstop.
 
If anyone is interested I'll put up pics in Hints and tips.
 
Ray
 
Thread: Titanium
12/01/2011 17:04:46
Thanks for that John S, I'll give them a ring.
 
Yes its for anodising.  I want to make springy clips to clamp across the threads as per production lines.  I can make the 'springs' in various sizes as there only a set number of threads used.  (T thread, C thread stc)  At hte moment I use ally wire but this doesn't always give good contact and where it touches you end up with white lines.
 
If I can't get the strip at a reasonable price I'll continue making toolmaker type clamps in PVC with 2mm titanium wire as the prods. I have a lt of 2mm titanium wire.
 
Thanks for your help.
 
ray
11/01/2011 22:03:06
Help wanted again.  I've got the chuck jaw problem sorted and I'll put up some pics later this week.  I now have a problem sourcing raw material. I have searched the net but so far no one seems to want to sell small amounts.  What I want is Titanium strip about 3/8" wide by .050" thick grade 1 or 2. This is to make spring clips.  Does anyone know where I can buy about 10 ft of this?
 
cheers
 
Ray
 
Thread: Trevithick's 1804 Loco
09/01/2011 20:27:28
Just had a look at another book. This contains a pic or 2 together with a couple of line dwgs.  I cannot scan it but if you go to your local library and ask them to get  this, then you can do the neccessary.
 
Railways: The Pioneer Years.
ed Fletcher and Taylor  pub 1990  The Bath Press.
ISBN  1 85170 363 2
 
 

Edited By macmarch on 09/01/2011 20:28:16

09/01/2011 19:34:46
According to a book I have Trivithick's engine of 1803/1804 does not have a complete set of drawings. There is a model of it in the Science Museum that is beleived to be basicaly correct.
 
 
Thread: questions on using gun blue to protect hand tools
09/01/2011 11:17:37
Hi Dave,
 
Do you use any form of heating?  How do you enter your worshop?
 
I had this problem until I locked the up and over garage door, lined the inside with rock wall insulation and then erected a plasterboard wall. This now hold shelves. If I need to open the door it only takes about 20 minutes to dismantle the wall.  The benefit being there is no outside damp air coming in under the door.  I added a side door to the garage. I live in the fens so we know all about damp air. My heating consists of an oil filled rad, (Lidl) set to hold the temp at 5C.  The little fan in the side of the heater will bring the temp up to 20C in about 15 minutes.
 
You say that the rust enjoys attacking your tools.  Do you suffer from the engineers curse of rusty hands? If so then I would reccommend the use of PR88.  (do a google search).
 
cheers
 
Ray
 
Thread: Chuck jaws
07/01/2011 18:15:43
Success!  Gave them a good going over with the oxy and buried them in preheated sand, (haven't got a coal fire)  The bandsaw took the unwanted bits off.  Drilled and tapped then fitted 1" x 2" x 1/2" steel 'soft' jaws.  Job done.
 
Just goes to show that you learn something everyday, 50 years in engineering and didn't realise that you can soften hard jaws.
 
 
cheers
 
Ray
 
05/01/2011 20:07:54
Forgot about ash.  Used to use it back when I was an apprentice. we had plentiful supplies from the old pot bellied stove in the workshop.
 
ray
 
05/01/2011 17:38:08
Well I've checked the jaws and they are indeed hard, in fact a deep grind at the back shows that they are H & T through.  I must asume the spec is something like EN8 ,16 or 24T.  The drills I have that will cope with spanners etc don't even look at them.
Tomorrow morning I'll give  them a good soak in the oxy and go from there.
 
The article by Harold Hall makes very interesting reading. I don't need the jaws to have full form teeth.  I will only be holding light section Aluminium discs so no great clamping power needed.  Therefore even though I will anneal the jaws I will also make a set but use H & T silver steel pins as the teeth.
 
Again thank you for all your help so far and I will put up pics of the final result.
 
Sid,  Apart from oxy any decent propane burner with a reasonably large burner will do the job.  Just remember that the heat treatment will have been done in an oven. Heat to dull cherry, (its not the temp yopu require), and hold it there for a good 5 minutes, 10 would be better. Then bury the part in dry sand. You need to get the cooling to take as long as possible.  Its all to do with grain recrystalisation.  This is why when you have hardened silver steel and then proceed to temper, It as best to put the part in the oven. This will allow time for the grain structure to change correctly. Also there is no panic to dunk the part as the colours run. You can watch the parts change colour slowly.
 
 
cheers
 
Ray
 
04/01/2011 21:10:26
Wow, lots of ideas. Thank you all.
 
The chuck in question is a brand new 5C 3 jaw. I will take one jaw to the grinder. If case hardened then I'll give a good blast with the oxy.  Also just looked at Harold Halls article in MEW 146.  I'm tempted to have a go and make a set or two. Has anyone done it?
Whatever happens I'll post the results.
 
cheers
Ray
 
04/01/2011 19:21:10
Thank you John, 
I have a set of these drills that I use for drilling spanners.  I'll give them a try.
Do to the nature of what I will be using them for I need to be able to achieve a flat surface to clamp the 'soft' jaws to.  I use external and internal jaws. The main problem will be to tap the holes! 
 
cheers
Ray
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