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Member postings for D.C.Clark

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

Thread: Whistle Construction
21/02/2010 12:08:52
Here's a link to a forum dedicated to horns and whistles:
 
 
David Clark in Southern Maryland, USA 
Thread: Bending steel tube
08/02/2010 14:51:52
Fill the pipe with water.  Freeze it, bend it, thaw it. 
Lower melting temperature than lead or Cerro alloys, safer
 and easier to work with, much cheaper. 
This time of year, in most of the Northern Hemisphere, you
don't even need a freezer.
 
David Clark in Southern Maryland, USA

 

Edited By David Clark 1 on 22/02/2010 15:08:56

Thread: Scale nuts and bolts
12/12/2009 17:09:26
Posted by Paul Boscott on 12/12/2009 14:07:34:
 
I know that sometimes what is right on the calculations does not look/feel right in practice.

 
That's the crucial point.  A model has to look right, and the human eye is not calibrated.
 
I'm working on a 1/12 scale animated model of Fulton's steam boat engine.  Working from period drawings and sketches, even scaling photos of a reproduction built in 1905. Visiting museums and their archives to study the hardware and fittings on engines and other mechanisms of the period.  It still comes down to what looks plausible.
 
It helps a lot to solid model in CAD, then print out full scale.  My model will be almost 36 inches long, so I go to a print shop with a large format printer.  Even this doesn't always ensure that the model will look right, though.  So, I've made a prototype, and several design studies of component parts.  Been at this over a year, and have yet to make the first part for the museum-grade model.
 
David Clark in Southern Maryland, USA
 
 
 
Thread: Why do I do it?!
08/12/2009 13:11:18
It was once fairly common to see the acronym CADD -- Design and Drafting.  There is better reason today, as modern packages have extensive design tools: finite element analysis, mass properties, motion, moments of inertia, strengths of materials, bolted structures, etc... etc...
 
These immensely powerful tools make it possible for the educated, but untalented, and inexperienced,  designer  to screw up in ways his predecessors could only dream of.
 
Regards,
 
David Clark in Southern Maryland, USA
retired NASA techie
Thread: Fire Extinguishers For Small Workshops
07/12/2009 14:47:17
I keep a dry chemical fire extinguisher in each of my workspaces.   Also a steel can with a tight fitting lid for flammable waste.  Smoke detectors too.
 
My band saws and larger drill press have to live in an outdoor shed.  When I'm working out there in winter, I use propane and kerosene heaters.  So have a carbon monoxide level detector and alarm in addition to all of the above.
 
David Clark in Southern Maryland, USA
Thread: Loctite on shafts
07/12/2009 13:27:48
What flavor Loctite?  They make many different types of adhesives.  Some will release at fairly low temps: < 450F ( 230C ) others will not.
 
Does it say "Threadlocker" on the label?  Loctite red or green Threadlocker will release with heat.  Blue should break pretty easily with a wrench.
 
All the info is available at http://www.loctiteproducts.com/  They are also very helpful and responsive to inquiries, in my experience.
 
A counter-top toaster oven is a handy thing to have in the shop.  I use one to release adhesives, melt machinable wax and cerro alloys.  Coat mild steel parts with motor oil and bake, for a nice rust resistant patina.  Dry things.
 
Give your wife a new one for Christmas, and take the old one. ( Nota Bene:  It is important to perform these steps in the given order. )
 
One of those little palm-sized refillable butane torches is also useful for releasing adhesives when you just want a quick, point application of heat.
 
It is vital to have excellent  ventilation.  Heating cyano-acrylates, especially,  is risky business how ever you do it.  I take it outdoors and stay upwind of the work.
 
 David Clark in Southern Maryland, USA
Thread: true Space
19/11/2009 14:21:24
I learned pencil drafting 40 years ago.  In 30 years with NASA, used pretty much every CAD and CAM system ever made.  Also taught them in community college and apprenticeship programs.

My all time favorite for intuitive ease of use was AutoDesk Inventor.  Couldn't afford it in retirement so switched to Alibre Expert.  Like it almost as well.
 
Now I'm at home, clock making and model engineering.  I make animated CAD models of my designs only because I'm weird enough to think that's almost as much fun as making things.
 
But I haven't made anything in retirement that I couldn't  have designed and drafted just as well, and almost as quickly, with a pencil.  (ain't rocket science)  I still have my drafting equipment, (Hell, I still have my slide rule.) and there are times when I just don't feel like messing with a damn computer.
 
Haven't done any CAM at home, and don't expect to.  Me and CAM go back to when we were hand punching programs on paper tape.  For simple 2-1/2 D parts, I can type code faster than I can post process a CAD model.
 
My favorite answer to almost every question is, "all of the above".  So, my advice is to maybe step back a generation (or 2).  Go for low-tech, unless you want the hi-tech for it's own sake.  In that case, get Alibre and have fun with it.   What ever you do, have fun with it.  Or why do it at all?
 
David Clark in Southern Maryland, USA
 
 
Thread: Why do I do it?!
18/11/2009 13:30:58
I don't make mistakes.  I make "test pieces".  If it doesn't turn out right, it was a test piece.  Everything made prior to the final finished product is a test piece.
 
I've never made an actual mistake in my life -- made lots of test pieces, though.
 
David Clark in Southern Maryland, USA
Thread: Hints and tips
17/11/2009 14:24:23
When machining very thin sections there are 2 issues; holding the work without distortion, and machining without deflecting or even tearing the part.  One solution is to embed the work in machinable wax or cerro alloy.  Fill your thin tube with one of these casting materials, machine, then melt the filling material out.  These materials can be reused any number of times.  They are also useful for making temporary jigs and fixtures as they can be cast around the work to achieve perfect contact over any area.  Think also liquid shims, poured into a void and allowed to harden -- melted away when done.  Handy stuff.
 
David Clark in Southern Maryland, USA
15/11/2009 18:13:28
Posted by Gordon W on 14/11/2009 10:07:44:
Here's two old tips, I've not seen written down, probably too basic for most of you lot. 1:-after setting up for thread cutting put a pencil in tool post and "cut the thread" then check pitch, saves some grief. 2:-for all of us without QCTs ,glue the shims to the tool after setting CH. Any old glue will do, saves some grief.
 
 
Re 1: Alternatively, paint the work with layout fluid or marking pen.  The cutting tool at zero depth should just cut away the paint; verifying the pitch, cylindricity, and the zero setting.
 
Re 2: Good idea, thanks.
 
David Clark in Southern Maryland, USA
Thread: Science and Engineering Tourism in Britain
29/08/2009 14:47:49
Hello Group,
 
I will be in London next week, then return to the States on a cruise with day stops in Edinburgh and Dublin.   What are your top recommendations for museums, tours, etc?  I'm most interested in early steam, the origins of the scientific and industrial revolution in Britain, development of clocks and scientific instruments.
 
I know this is a very short time in which to see much, but I'm considering this an exploration for much longer visits in the next few years.  So far, my favorite museum in Europe is the Deutsches Museum in Munich.  Does London have anything to top that?
 
Thanks for any suggestions, best regards,
 
David Clark in Southern Maryland, USA
Thread: Diamomd tool holder
06/08/2009 21:16:33
Thanks Chis,
 
The tool holder does not interfere with the maximum clearance between the Sherline spindle axis and the top of the cross slide table.  For larger diameters, those that extend below and in front of the table, the tool is limited to facing and about 3/4 inch of turning.  This could easily be extended, but I would make the tool holder wider for greater stiffness.
 
Thank you, Keith, for correcting me on the year of issue.  I've attached some "in process photos".   As you see, I created the double compound angles by using Sherline's tilting angle table, rotated on the mill table.  This allowed me to machine all the angles in one setup, only changing the position of the the mill vise on the angle table.  The material was 12L14 steel.
 
 

Layout and roughed out.
 

Double compound angle setup
 

Milling the front face
 

Drilling holes for clamping screws

Edited By D.C.Clark on 06/08/2009 21:18:37

Edited By D.C.Clark on 06/08/2009 21:20:12

06/08/2009 13:06:17
Hello Group,

Here's my implementation of a tangential tool holder on my Sherline lathe.  I  adapted my design from an article by Marcelo Jost in the January-February 2008 issue of "The Home Shop Machinist" .  He was inspired by an article in Rudy Kouhoupt's Shop Wisdom volume 3.
 
I've been very pleased with it's performance.

 
David Clark in Southern Maryland, USA
Thread: Verge & Foliot details
20/07/2009 22:02:23
Nice job, very handsome.  How did you make the dial?
 
Best regards,
 
David Clark in Southern Maryland, USA
15/05/2009 19:06:44
Hello,
 
I purchased Conover's book some years ago and made my own adaptation of his design: added a minute hand, used a cycloidal gear cutter instead of home made triangular tooth cutter, made a windlass for braided brass weight cord, and other practical and aesthetic changes.
 
I've created an album here and posted some photos.
 




I can recommend the book as a good introduction to the design.  I'm not myself interested in making an exact copy of anything, preferring to pursue my own ideas.
 
You don't say where you are located.  I've visited many clock museums in Europe, and can also suggest the museum and library of the NAWCC in Pennsylvania.   see:
 
http://www.nawcc.org/

Best regards,
 
DC
 
David Clark in Southern Maryland, USA

 


Thread: Congratulations
14/05/2009 13:15:29
I look forward to watching this site develop.
 
Best wishes,
 
The other David Clark, in Southern Maryland USA, who will sign himself:
 
DC
 

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