M3 Grant (Lee?) scratchbuilt... or that's the plan anyway...

[Rob1970]

Today I did some more "Arts and Crafts", making the rear deck and the back plate of the upper deck. Pretty much stuck the paper model parts to the poster board, cut along the line and the parts just slotted right in...



Emboldened by that success, I thought "The hell with it..." and got out my stock of ABS sheet.


Some measuring and scribing resulted in a 3mm thick top piece and two 2mm thick side pieces. I took the exact measurements of the paper model piece for the top, then scribed all around at two mm from the edge. For the two side pieces I removed those two mm and welded the side pieces into place.


A piece of ABS angle profile strengthened the joint. I will be bracing the sides to the top with larger braces made from ABS sheet to make sure the box is and stays straight while I wrestle with getting the angled side and glacis pieces into place.


And as you can see the whole thing falls neatly over the HL hull. The line is where the fender will be cut away to be replaced by a thinner fender in the correct shape.

The plan now is to finish the "boxy" bit of the upper hull, then design and 3D-print the cast sponson. The finished box bit will allow me to design on the fly to make that sponson fit perfectly. I'm aiming to make it one solid piece that will just slot into the space left in the sheets of the box...


...just like the real thing.

To Be Continued...

TTFN,
Rob

[Herr Dr. Professor]

WOW! just WOW! The whole M3 upper hull was a welded up mass of steel plate. Yet I don't think I would even have realized that the M3 could be made up of flat ABS.

[Rob1970]

WOW! just WOW! The whole M3 upper hull was a welded up mass of steel plate. Yet I don't think I would even have realized that the M3 could be made up of flat ABS.

Not welded, but riveted. Even simpler. And well yeah, pretty much all flat sheets. It's basically a box with some angles thrown in for variety. The only "organic" bits are the turret (and even then the Grant more than the Lee, the Lee turret is basically a cylinder with one edge flattened at an angle...) and the sponson for the 75mm gun. And even that should be doable with flat sheets and a lot of sanding.

Paper models is a great tool to help with figuring out the angles. Add to that a good scale model to take measurements from and to puzzle out some of the construction and I think I could scratchbuild other tanks as well. Already on my list is a Crusader Mk.III. I have the paper model, and the 1/32 Airfix kit as a reference to go on. Hardest part would be figuring out how to do a working suspension and lower hull "on the cheap". And even that seems to me not that hard, being a Christie suspension. That's basically arm and springs.

[Rob1970]

Some more work done on the Grant. With the parts for the Firefly -still- stuck in Import Tax Limbo, it's the only thing to do. So onwards!!!


First order of business is squaring up what I have constructed sofar. A spacer at the back...


...and a large bulkhead at the front. It's just glued at the sides and the little triangle at the front for easy removal later. Also added some angle profile to rest on the HL hull.


And back to building up. First I decided to add the small plate at the rear of the hull/turret area. I started by removing a 2mm strip from the rear and a 3mm strip from the angled pieces.


It's a small piece of 2mm ABS sheet, with the edges that meet the other pieces already angled and the small gun-port cut out. Might use that spot to install the main switch later. Or not. Plenty of hatches in this beast anyway.


Time to start building up the front. As ABS is a lot less forgiving than paper I decided to use a bit of a roundabout method and made a templatey jig (or is it a jiggy template?) for the front glacis first. So I nailed (yes, nailed...) the boxey section to the HL lower and got to work. As I know the size and angles of front pieces, I can use the resulting edge to make a perfectly shaped and sized piece for the front-left of the glacis.


I filled in the resulting "hole" with strips of ABS resulting in a perfectly shaped template for the left side of the glacis. That was transfered to a sheet of 2mm ABS and cut out, with a little bit extra at the top so I could cut it flush with the top deck later.


After angling some edges (the rear edge of the infill piece and the edge of the deck where it meets the top of the infill piece) I welded it into place with MEK. I beefed up the inner weld by dropping in some bits of round stock and soaking them with MEK, forming a pretty solid connection.


The top was cut flush with the top of the deck with a PE sawblade. Those blades are awesome, and great for flush-cutting or even cutting out hatches in hulls.


And the template lines up perfectly, and can now be used to get those two front plates right. I just hope I remember to cut out the driver's hatch before I glue them in place. I forgot that with the small gun port in the angled piece of the glacis, and had to drill it out while it was already glued together...

To Be Continued...

TTFN,
Rob

[Herr Dr. Professor]

Hi, Rob. I am away from my books for a few days, and for even a retired prof. being away from the books is debilitating. I thought that after a time, the M3s were welded because rivets were weak and dangerous to the crew. Maybe I am confusing the M3 with something else.

[Rob1970]

Hi, Rob. I am away from my books for a few days, and for even a retired prof. being away from the books is debilitating. I thought that after a time, the M3s were welded because rivets were weak and dangerous to the crew. Maybe I am confusing the M3 with something else.

Well, you were not wrong... kinda...


There was a welded variant (M3A2, a proof of concept for welded hulls) and even a cast hull variant of the M3 Lee, the M3A1. 300 of those were build and mostly used for training in the U.S.


Many if not all riveted variants were retrofitted in the field. By retrofitting I mean that many of the rivets were welded over on the inside when it was indeed found that they would fly around inside the hull when hit from the outside, doing all kinds of damage.

Rob

[Model Builder 4]

Hi, Rob. I am away from my books for a few days, and for even a retired prof. being away from the books is debilitating. I thought that after a time, the M3s were welded because rivets were weak and dangerous to the crew. Maybe I am confusing the M3 with something else.

Well, you were not wrong... kinda...


There was a welded variant (M3A2, a proof of concept for welded hulls) and even a cast hull variant of the M3 Lee, the M3A1. 300 of those were build and mostly used for training in the U.S

Looks like something that came out of the Jelly mould a little too early

Cheers,Lee.

[Rob1970]

Progress!!! And a great success it was!


I used the jig to correctly size, shape and angle the two pieces for the front glacis, glued them in place and cut them flush with the top and left side. The right side will take some more measuring and figuring out. And guess who -again- forgot to cut out a hatch...


I cut the right side to the correct size and angle using the paper model parts as a template. The roofline jumps in a tiny bit according to my references, to make space for the cast sponson. Also cut away the top of the transmission cover on the right side. This results in a hole where that sponson and some other assorted bits are going to end up. Just for my own satisfaction I pasted the parts for the fender, lower half of the sponson and the one piece of steel plate to fit into the right side onto 3mm poster board and cut them out.


Well that makes me happy... It fits like a glove! Just needed to cut out a small bit for the one gear that sticks up and a small square on the underside where the screw for the transmission cover sits... And this is a 3mm layer of posterboard....


Another 3mm layer (which is part of the casting of the sponson) hides the gear-cog... Sooo... this is where I am going to have to cheat a little in milimeters to hide that cog. Maybe do something clever by slightly angling the pieces. I pondered lowering the whole gearbox at the rear end to create a little clearance, but don't think I can get away with that as it would make the drive wheel noticably too low.

But yeah, sofar I am happy...

To Be Continued...

TTFN,
Rob

[HERMAN BIX]

You Da Maaaaaan !!
You will soon have your own Lee oddity !

[Rob1970]

The hull is nearing completion!


...yeah... in 1/35... If only it was this easy...


Still a lot of measuring, sketching, comparing and referencing to do...


...so I end up with lots of references.


A few hours in Tinkercad and some test prints later I end up with something that actually slots in with a very satisfying "thunk!"... Just the basic shape that still needs a lot of refining. But it's a start.


Still a lot of work to do, but it's getting there. Between my references, the pictures from various sources and two model kits to compare my work to, I should be able to make something that at least satisfies me personally.

To Be Continued...

TTFN,
Rob