scale drawing

Dan Williams · Post by **Dan Williams** » Sat Sep 13, 2008 1:43 am

Hi all,does anyone know where I can find scale drawings,of the M2 half track? Dan

Dan Williams · Post by **Dan Williams** » Sun Sep 14, 2008 4:32 pm

Thanks David the drawing are nice,but they don't say what scale there in.
What models do you have? thanks again from Dan

Dan Williams · Post by **Dan Williams** » Mon Sep 15, 2008 6:00 am

Hi David,Yes I am building the basic M2 model.And I have some problems to figure out.Like how to keep the doors close.And Armortek gave me an extra part and shorted another.I recd 2 packs of lens cover,and no brush guards.So I may make them.And I want to make the strap to hold locker door closed.This is a sample part.I like the hold downs but I wish they were made of steel,and could be bolted in place.
But I do like combats german half tracks,with the machine gun turret in the top.they used an M2 with a roof.
So are you making your trailer? Dan

Ad Wouterse · Post by **Ad Wouterse** » Mon Sep 15, 2008 6:14 pm

Hi guys,

Great to read that things are moving in the M2/M3/M16 section

How about some pictures ?

Tim Bowman · Post by **Tim Bowman** » Mon Sep 15, 2008 6:40 pm

Hi Dan and David

Ad Wouterse wrote:Hi guys,

Great to read that things are moving in the M2/M3/M16 section
How about some pictures ?

I second Ad's comment and request.

Regards

Tim

Allan Richards · Post by **Allan Richards** » Mon Sep 15, 2008 8:31 pm

David,

Thats very impressive work on the front axle, I am not familiar with this kit or vehicle but I take it that the front wheels were driven in the actual vehicle, will yours be driven in the model? What does the Armortek axle look like?

Dan Williams · Post by **Dan Williams** » Mon Sep 15, 2008 9:00 pm

Hi David,Wow your front axle looks great.I'm building a stock Armortek kit.Only 1 time did I buy a part for a model.I been painting my model for a few weeks,I just got a new Q,of paint.
I don't know how to scratchbuild.But If I did I would make a Dragon Wagon in 1/6. Dan

Dan Williams · Post by **Dan Williams** » Mon Sep 15, 2008 9:24 pm

Hi David,How do I post my pictures to my post replys? Dan

Dan Williams · Post by **Dan Williams** » Tue Sep 16, 2008 2:12 pm

Hi David,
Geneva is 50 miles west of Chicago. Dan

Tim Bowman · Post by **Tim Bowman** » Tue Sep 16, 2008 4:51 pm

David,

Thanks for posting the pictures! Your parts look GREAT! Your scratch-built axle housing is just awesome Super work! Nice comparison photo too of the original.

I can't wait to see your project as it progresses.

Best regards

Tim

Ad Wouterse · Post by **Ad Wouterse** » Tue Sep 16, 2008 5:24 pm

Hi David,

This really is a work of art, quoting one of our Swedish friends.
How can we convince you to start a small series of castings ?
I certainly would be interested.

Robert E Morey · Post by **Robert E Morey** » Fri Sep 19, 2008 5:52 am

Dave,
Great work casting your first piece! Wow thats nice work for your first time. What kind of material are you casting? Just curious, white metal, resin or brass?

Awesome stuff. Keep us posted on your progress. I hope to have an M3 someday <A-tek kit>

Bob

Robert E Morey · Post by **Robert E Morey** » Sat Sep 20, 2008 6:42 pm

Dave,
I use a Pewter type alloy as well for my white metal castings. It makes nice looking parts, is farely hard and strong, but is expensive like you say. $250+ for a block of 25lb. I haven't bought any in a while, so it may be more now.

How do you think the white metal (pewter) will hold up on your axle assembly? Esp if you make it driven? Are you using spin casting or RTV molds?

Just curious on your thoughts and technique.

Thanks, keep up the great work!
Bob

Robert E Morey · Post by **Robert E Morey** » Sun Sep 21, 2008 6:14 am

Hi David,
Yes I have a small benchtop spin cast machine. This process is really fun, but takes a sizeable investment in equipment. It uses centrifical force from the rotating mold to inject the metal into the mold. You simply get more injection pressure on the mold than gravity pouring.

But I also use RTV molds for larger castings. This is the easiest and cheapest way for beginners. Its pretty amazing what you can make with a little practice.

From my experience casting tubes (long thin walled cylinders) is very difficult, the mold must be vented well, otherwise trapped air will prevent the tube from forming before the metal cools. You want gravity to help fill the mold, so pour the metal straight down into the tube (ie have the tube cavity vertical). You can also use a teflon rod core (machined to correct diameter) to make the ID of the tube.

It would be better as you have already surmised to make the housing cast and have the tubes machined and epoxy glue them into the housing. Make your walls thick in the housing and it should be fine.

Brass/Bronze is much more difficult to cast because of its high melting point -depending on the alloy it can be over 1000F! To get high details in brass it must be cast into a plaster high temp (investment cast-Lost wax) mold. Sand casting brass would be ok for rough less detailed parts that you would machine afterwards - but no good for detail parts. High temps will destroy RTV which can only handle maybe 500F - so it will not work with brass/bronze.

Pewter, and tin/silver alloys are about the strongest material you can cast safely in RTV molds.

A couple books I have found helpful:
How to cast small metal and rubber parts, William A. Cannon, ISBN 0-8306-0414-6, Published by TAB books (MgGraw Hill)
Complete Handbook of Centrifical Casting, Philip Romanoff, also published by TAB books (no ISBN).

I can't remember where I got the books, I think Lindsay publications? http://www.lindsaybks.com

Hope this helps? Keep practicing, you are getting good results, so you're doing things right!
Bob

Robert E Morey · Post by **Robert E Morey** » Sun Sep 21, 2008 7:10 am

David, Amazon has both books, but the spin cast book is quite expensive. The other is better for your needs anyway. -Bob

http://www.amazon.com/Cast-Small-Metal- ... gy_b_img_a