453 replies to this topic

[dc-65x]

Nice!   

[Phloidboy1]

GREAT STEP BY STEP IMAGES.

[Regis4446]

   “light is right”   Colin Chapman

[Alan Draht]

The next step is to draw/ scribe outlines of the outside form and the inside opening shapes of Husting's magnesium left and right frame plates.

 

The frame's outside form is drawn.

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[Phil Smith]

Really nice work! 

 

A couple of questions. What kind of mill is that? What kind of tool did you use to cut the large hole? Annular? What kind of chuck are you using to hold the end mills? And why a chuck and not an end mill holder or collet?

[Alan Draht]

Thanks, Phil!  

 

I use Sherline miniature "tabletop" machine tools, both a mill and a lathe.  Each machine is mounted onto a separate 24" x 12" x 1" plastic laminate shelf board that has rubber feet under it.  They are portable (not that I carry them around).  They don't take up much space.

 

This Sherline mill is an 8-direction machine, so it replicates all of the movements of a full-size Bridgeport.

 

The machine tools are parked at one end of a desktop under which there is a file cabinet supporting the weight of the machines on top.  When not in use, they can be easily covered.

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[Alan Draht]

The large hole for the armature opening was cut with a carbide-tipped 3/4 inch hole saw.  I love working with magnesium.  It cuts like butter.

 

I have a small set of collets that I rarely use.  For a hobbyist like me there are too many different sizes of collets needed to span the range of end mills, drills, reamers and cutters that I use, so it's not practical.

 

Sherline's chucks are extremely accurate and they make it easy to switch from a center drill to an end mill and so on without fiddling around with different size collets.

[Alan Draht]

The next step is to draw/ scribe outlines of the outside form and the inside opening shapes of Husting's magnesium left and right frame plates.

 

The inside opening shapes are drawn.

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[Martin]

Alan, I am sure you know this but for all that do not. Keep your chips (swarf) in a safe place.

A shop where I worked did not clean the chip in time. There was a spark and it burned the mill down to a write off.

[Dave Crevie]

Right. Magnesium chips will burn hotter than an oxy-acetylene torch, and can't be put out with water. I worked in a magnesium die casting

plant for 30 years, and magnesuim fires were nearly a daily occurrence. Boric acid is used for big fires, a class "D" halon fire extinguisher

for smaller ones. Keep one handy.

[Alan Draht]

Yea, I've been vacuuming magnesium chips up after nearly every cut.

 

This project is all about making chips, some aluminum, but mostly magnesium. 

 

You start out with two magnesium plates, 10"  x 1.25" x 1/16", and you reduce them to these slender forms and lots of chips.

 

I don't know what percentage of material is removed or what remains.  I'm guessing it's 65% removed, 35% remains. 

[Alan Draht]

I used the drawing made on tracing paper to create a pattern.

 

I used the pattern to draw the left side frame's final outside form in pencil.

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[Alan Draht]

I scribed the outside form onto the magnesium plate using the lines drawn in pencil as a guide, as well as the original french curves used to create the drawing.

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[Alan Draht]

Once the outside form was scribed onto the plate, I cut out the inside openings of the pattern using an Exacto knife, then used the pattern to draw the inside openings onto the frame plate.

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[Alan Draht]

After drawing the inside opening shapes onto the plate, I scribed the shapes onto the plate.

 

This completes the process of transferring the drawing to the left side magnesium frame plate in final scribed form.

 

The next step is to screw the left and right side frame plates together again, then clamp that assembly onto the mill table, and cut the outside form and inside shapes out using end mills and files.

 

Before I do that, however, I need to spot the locations of where 00-80 size screw holes will be drilled into the sides of both the left and right side frame plates which will be used to fasten 0.016" thick aluminum sheet material to the top of the assembled frame for the top cover or "body".

 

Gene Husting located his at beefy sections of the frame's top stiles using fold-down tabs of the aluminum sheet to screw horizontally through the material.

 

He avoided using the tops of the frame rails for vertical attachment points because even 00-90 size screw holes create weak spots in the 1/16" thick magnesium.   His 1966 Rod & Custom article explained this issue and how to avoid it.

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[Ramcatlarry]

FYI:  https://www.sherline.com/    

[hiline2]

FYI:  https://www.sherline.com/    

 

 

HAHA how many of us looked it up too !

[Alan Draht]

Sorry.  

 

I forgot Sherline is relatively unknown.

 

When I was a kid I wanted a Unimat in the worst way.  Years later I Iearned that the Unimat wasn't very accurate or precise.  Unimat's manufacturing practices and machine tolerances were sloppy.

 

Founded by Joe Martin, Sherline sort of took over the market for miniature machine tools when there weren't any other brands as well made and precise as Sherline's equipment.  Sherline manufactures everything in the USA, too, which is nice.

[Alan Draht]

So, I bolted the two sides of the frame back together again and mounted the assembly in the twin vise set up I have on the mill table.

 

I began by milling out the interior shapes of the frame.

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[Alan Draht]

After the interior openings, milling the frame's outside form came next.

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[Alan Draht]

...

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[Alan Draht]

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[Alan Draht]

I machined the frame's rear end and nose further to reduce the amount of sawing needed to finally cut the frame assembly apart from its remainder, and to minimize the amount of filing required to reach the scribed shape outlines.

 

Other than that, the frame for this 1966 Gene Husting Rod & Custom dragster replica is done.

 

One of the project's last steps will be sanding/ polishing the magnesium frame's left and right sides ... after test fits of all components, including final assembly/ disassembly.

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[don.siegel]

Nice work Alan, 

 

Could you turn out 100 or so of these for us drag fans? 

 

Thanks! 

Don 

[Alan Draht]

Thanks, Don!  

 

With the right kind of full-size CNC-controlled equipment, that could be done.

 

The kits for sale would be costly, though.  Magnesium sheet is pricey and most of it ends up as swarf.  

 

So far I haven't screwed up anything.  I'm glad to have reached this point.  It's been useful preparation of my next project, replicating Manuel Maldonado's 1966 Rod & Custom "Car of The Meet" dragster.

 

Ah, but I'm getting ahead of myself...