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Member postings for David Haynes

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

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Thread: Silly Question about Simplex
09/05/2011 08:24:11
I have recently bent a 'joggle' into crosshead plates for a much smaller loco. The principle should be the same, using the brench vice to press the shape of the plate. You first make a die pair and then press the plate between them in the vice. See my poor example at https://picasaweb.google.com/Dave22fair/Loco15Crosshead#.
 
Dave
Thread: Balancing bench grinding wheels
23/04/2011 12:56:49
Good point about the KE in grinding wheels. At what point is it it time to replace them, what are the safety considerations for use, apart from the obvious - goggles and common sense, when are the tell tale signs that replacement is due. I would suspect a given hour usage may play a part in programme replacement, but I don't know what the figure is. Your thoughts please folks.
Dave
Thread: Making pin drills
27/03/2011 17:31:06
800rpm may be ok for turning but not cutting! I'll try the slower speed. Any advice on getting the best shape for cutting edges?
27/03/2011 17:02:37
What am I doing wrong with my pin drills. I have a silver steel round, say 3/8", drill for pin size, create a cutting edge, harden and temper and yet it won't cut very well.
 
Any advice, thanks
 
Dave
Thread: MT2 collet slipping
19/02/2011 12:03:50
Thanks for that. Not fair of me to tease though; I omitted to put the usual caveat after "complete grip of the cutting tool with only hand tightening the chuck. However, the nut should be then tightened as appropriate with the correct spanner"
Dave
19/02/2011 08:21:00
Hi All,
Just thought I'd let you know the collet situation, after over 3 weeks since first going down the collet route. I contacted the supplier, RDG Tools, (who also supplied the cutter). They are a good firm and they've been happy to take the MT2 set back and exchange it for an ER32 collet chuck that screws on the ML7 mandrel. I also managed to pick up a few used good condition ER32 collets. Instantly I have found a massive improvement; no more having to take off the change wheel cover or use a draw bar and complete grip of the cutting tool with only hand tightening the chuck. And the other surprise is how the cutter obligingly auto ejects when I undo it all!

Thanks,
Dave

Thread: Swarf
15/02/2011 19:52:42
I use old washed tins that are due for recycling as my Fe scrap bins and washed aluminum food trays for non-Fe scrap. I also saw in half old pressurised Al empty aerosol cans for non-Fe scrap. When half full, I squeeze them in the vice and crimp over the end, then no stray swarf gets out. All go into the council scrap tin box.
Dave
Thread: MT2 collet slipping
09/02/2011 00:27:06
Hi again folks,
As this rumbles on with lots of interesting discussion, I am still looking for a solution. I have just tried out a witness marker on the cutting tool, but I am using layout blue, which is the nearest I have to the correct product. My layout blue often rubs off when I don't want it to but, despite sitting very snugly in the associated collet, none of the marking is witnessing when I push the cutter into the collet. Looking down the mandrel taper, I am fairly convinced it is in good condition. I have cleaned the tool of oil etc and I have tried a drop of slide oil on the MT2 taper in the hope that it will help it slide in better and thus clamp the tool better, still with no luck; I have even tried only pushing the tool bit half way along the collet with the thought that this will allow more pivot in collet. Still no luck, the tool still rotates even when a lot of torque has been applied to the draw bar. So many people have said they have had no problems in using MT2 collets for milling on a lathe, so I am sure the MT2 solution must be out there somewhere!
 
Oh, and the drawbar can be screwed in easliy by hand!

With thanks,
Dave
07/02/2011 11:44:32
Thanks for your responses. The collet I have been using is a 3/8" collet and the tool a 3/8" four flute end mill. When the collet goes into the the arbor taper, there is the same positve wedge that I would expect from the tailstock taper. The cutter fits snugly into the collet and the tool need a little push with something soft, like a piece of wood, to slide it in. With the drawbar, I have used an all thread bar, so I simply screw the drawbar into the collet first, about 5 turns but stopping one thread before it is screwed tight, then place a large washer of appropriate bore over the drawbar and a nut tightens the drawbar. Most of the time the milling works okay but when there is a bit of a challenge to the cut, the cutter starts to turn in the collet. Regards, Dave
07/02/2011 07:12:00
Hi, after using the chuck for milling in my ML7 lathe I have now got bought a set of MT2 collets in the hope of improving the finish and operability. I am using a new end mill, have a rigid setup and have wiped any traces of oil from all four interface surfaces of the morse taper and tool. However I still experience intermittent tool slipping during milling. I am trying to keep my cut as shallow as possible, but still this occurs. Tool is 3/8" four flute endmill and speed is about 800rpm. The drawbar has progressively been tightened to a high amount and I am concerned that any more tightening may cause damage. I understand that use of a different type of collet may be a solution, but having just bought the new MT2 set, I am reticent to have to get another one when I believe this can be made to work. Many thanks, Dave
Thread: Cylinder Erection
28/07/2010 23:33:53
Just to bring things up to date, In order to locate the cyinder(s), the axleboxes were clamped at the height specified on the drawing but in doing so the boxes hadn't seated evenly causing the wheels to stiffen; slackened off, tried again and this improved things a little.  The piston is fairly free to move in the slide bar assembly and I believe all components are correct lengths.  The thing I have found awkward is how much stiffness is acceptable.  Whilst I don't expect any component to spin or slide freely under gravity or radial inertia when spun, neither do I expect anything to be locked solid.  It's knowing how much stiffness is okay! 80psi on a piston applies a lot of force, but I don't want to take this too much for granted.
 
The cylinder is true to distance from the driving wheel c/c and the piston rod is correctly aligned with the driving wheel c/c, the steam clearance at each end of the stroke seems to be about 1/32" and having drawn the layout to full size and sticking the drawing on the frame, I think it all seems the best I can do.
Any more suggestions are welcome!
Dave
28/07/2010 08:37:08
Thanks for that John, you caught me forum hopping!  You do it in the dead of the night!
 
I had a problem with the piston hitting the front cover, so I moved the cylinder about 1/32" forward and that stopped. I need to check the front and rear space is equal, but I think it will be. There is no piston nut and it simply a force screwed fit. The clunk occurs at front dead centre passing from forward to rearward movement. It may be a little play in the axle box in the horn.  However, the packing could be a point, I had to force it in and I suppose a PTFE ring would be a better bet.  Just that I would have to re make the piston to fit the ring and also make sure the PTFE working temperature was okay for SH steam.
 
By the way, with the boiler, thanks for Bryans link.  I forgot all about Don Young's 4F, that has a band at the throatplate.
 
All the best
 
 Dave

28/07/2010 01:07:55
I am at the stage of erecting cylinders on a simple 3 1/2" gauge loco and am uncertain if the setup is correct.  I want to be certain before drilling for frame fixing bolts. on the first cylinder.  I am fairly happy that the components are all correctly dimensioned but it seems stiff.  All I have fitted is the piston and rod in the cylinder, front and rear cylinder covers, guide bar, crosshead and connecting rod.  Yet when I turn the wheels it feels stiff and there is a bit of jolt as the wheel reaches front dead centre (jumping from one side of dead centre to the other),  This does not happen when the wheel reaches back dead centre where the movement is smooth.  The axles have been fixed at the correct operating height and I have obtained alignment of the cylinder with the centre of the driving wheel by use of a pointed sleeve over the piston rod before fixing the crosshead.  The distance from the centre of the driving wheel to the cylinder has been worked out from the drawings.  The piston has packing yarn fitted, which will make things stiffer but I don't know if this is too stiff or not.  Please can someone advise.  Thanks, Dave
Thread: Beginners 31/2" loco
16/07/2010 22:28:31
Hi Eddie,
 
That's quite okay.  An early experience I had in asking for a club comment was being told "if you want my opinion, you will scrap all the work that has been done so far and pick a proper loco". This was from a 7 1/4" enthusiast.  Other later comments have been much more supportive, but I have been put off discussing any difficulties in that forum.  That said, there are well documented difficulties and any mistakes are only expensive in respect of your time and not your pocket.  I made mistakes on driving wheels but was able to get a new set for much less than if it had been a bigger loco.
 
Dave
15/07/2010 10:42:43
Hi Eddie,
There is a lot of discussion either way on Tich.  A recent set of postings at another forum gives a journey towards a good little engine, but some wil still find it too much work for the results that many receive.  Have a look at http://modeleng.proboards.com/index.cgi under "Tich", and "Thanks NASA"
 
There are a lot of unfinished locos around and it seems to me that an unfair amount are of this little one, which is a shame really.
 
Good luck and all the best
Dave
Thread: Fuseable Plug in Q1
25/06/2010 08:32:02
Thanks for these comments.  Many well known small locomotives do not have fuseble plugs (I think Metro, Rob Roy, Mona, Tich... ), would it therefore be an improvement to fit one during construction?   Thanks, Dave
24/06/2010 00:51:34
Very interesting reading about the Q1 build.  I note that a fuseable plug has been specified as an important feature.  I think that there is no soft solder in the construction of the boiler so as I understand, this makes the fuseable plug redundant as the boiler now has a much higher failure temperature than if soft solder were used.  What are your thoughts?
Thanks
Dave
Thread: Model Mechanics
30/10/2009 01:08:02
It''s good to see that some archive magazines are now on the website. I see you have Model Mechanics, I was interested in finding Model Mechanics issues from 1954.  Is this the same magazine and where would I find these much older issues, the internet has not revealed anything to me of that vintage.
 
Thanks
 
Dave Haynes
Thread: Drewing out Stephenson valve gear
25/09/2009 23:06:10
Thanks for that.  I'll have to make sure I type in better light next time and check the text!
Regards, David
25/09/2009 10:09:21
I would like to draw out a proposed Stephenson valve gear for 3 1/2" between the frames with indirect drive (rocker shaft) and overhead slide valves.  Can anyone please advise me of the basic order of drawing out the components.  Thank, DaveH

Edited By David Haynes on 25/09/2009 10:21:10

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