@Thomcat
That Tamiya M1 release was bittersweet for me. They made a beautiful hull and turret but gave the kit a bunch of parts from 1981 and 1987 when it came out in 2011. Hollow wheels, a 30 year old tub for a lower hull. Tamiya needs to do right by the M4A1 76w. As much as love Tamiya what they did with the M1 release was just wrong. From the waist down it’s no good.
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I totally agree with you regarding the Tamiya M-1 kit. It is a disappointing kit in general. However, I use it as a conversion kit, since the basic hull is indeed very nice and better than the Italeri M4A1 hull. When the Tamiya M-1 came out, it was relatively cheap, so I bought a few to use for future projects. Also the figures are nice and can be improved with Hornet heads.
Then the Asuka M4A1 came out but at around twice the price of the Tamiya kit. BTW, as I understand it, there seem to be a consensus, the Asuka rear hull does not have the right angle? It should be near vertical, but is angled too much?
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@Thomcat
I asked folks here to chime in on the angle of the rear upper hull of Border Models kit and I think the consensus was that it’s supposed to be vertical straight up and down like on the small hatch hulls. I made it straight on my build. But these large hatch M4A1s are supposed to have what they call a “slight slope” in the “Son of Sherman” book. The Tamiya has a slight angle, the Border Models has a slight angle, the old Italeri has a slight angle, the old DML has a very slight angle too, but the Asuka that I just bought has no angle that I can see. So who’s wrong and who’s right? The “Son of Sherman” book mentions the introduction of a “slight slope” (pg 134 in first edition) which I believe is their way of saying slight angle (?) with the large hatch hulls. Basically I should’ve left the upper rear hull unmodified on my Border Models build because it was correct to begin with. The Asuka kit is wrong for a large hatch, it should have a slight angle on the rear, it should be approximately 1mm further out on the bottom edge of the upper rear hull than it is on the upper edge. I don’t think I’m going to correct that on my Asuka build, haven’t decided. Tamiya get’s my vote for the best hull of the group even if you include the indentation on the rear upper hull. AND it represents the only continental hull in plastic outside of the Tamiya M51.
Another small detail on the rear upper hulls is that only the PSC hulls seem to have a slight indentation in the area between the tracks. Once inside the rear sand shield brackets the hull should go up a tiny bit then across then down then across again at the opposite sand shield bracket. It can’t be much on the real tank, may a couple of inches if that. The old small hatch hulls did have a big indentation, perhaps something to do with clearing room for the exhaust pipes, I don’t know. But the continental hulls don’t have the indentation and they go straight across the back from corner to corner in one straight line. Tamiya is the only one of the kits that has the indentation molded in but it shouldn’t because it’s not a PSC hull, in fact it’s the only non PSC hull in the bunch, which makes it really unique in plastic. Honestly fixing this issue on the Tamiya hull is probably something most people won’t care to do, it’s barely noticeable but it would just require a small sliver of evergreen strip to get it flled in and straightened out. The other three, Border, Italeri, DML and Asuka are all PSC hulls but all of them lack the indentation and just go straight across corner to corner. Again not a hard mod at all, with some caution, a sharp hobby knife and a ruler and marker this mod can be made in a matter of minutes. Honestly it’s not noticeable enough that most modelers would be fine just leaving it alone. Certainly those kits have bigger fish to fry in terms of correctable inaccuracies.
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@Shermaniac I concur with the “slight slope”. My understanding is, there must be a slope in the object which is cast, in order for it to be able to leave the sand mould.
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That makes sense when making injection molds for plastic. It’s called drafting. It’s why supposedly square pieces are not square. Look at any plastic ammo boxes. Set them beside each other. The sides are not parallel. The parts need to be slightly angled to remove them from the molds.
However…
That is not necessary when sand casting. The mold is sacrificed during the casting process. I don;t know if the real thing is angled or ninety degree, but being sand cast is not a determinig factor.
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They still have to be able to pull the … what’s it called? the former? around which the mould is made, from the finished sand mould, though. Of course, by making the mould in several pieces that are then placed together, it would still be possible to have perfectly vertical sides to a casting, or undercuts — at the expense of needing more complex moulds that take longer to make and more care to assemble before casting.
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Sand molds could also be fine tuned after the former has been removed.
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There are a few images of cast hull Shermans built by PSC here:
http://the.shadock.free.fr/sherman_minutia/manufacturer/m4a1psc/m4a1_psc.html
I get the impression that the rear of the upper hull is not vertical,
it leans slightly forward
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@Thomcat
Yes, even the small hatch hulls require a small like 3-4% draft or angle (according to Kurt Laughlin) to come out of the molds without ruining the sand molds. But this is more pronounced than that. I’ll let people with more knowledge on the subject and more technical expertise and access to blueprints etcetera educate me on what that particular difference was. I’m not qualified to answer those questions, was it an extra 3% was it an extra 4%? I have no idea. That’s why I asked, but it’s clear to the naked eye that the upper rear hulls on the large hatch tanks have a bit, just a tad, more added “slope” than the standard 3-4% that the small hatch tanks required to remove them from the molds:)
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The pattern.
Draft is necessary to remove the pattern from the mold, not the part.
KL
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The slope off vertical on large hatch hulls was 10 degrees which is much more than needed for pattern draft.
This was to slope the rear hull, just like the rear plate on welded hulls.
The draft on the sides was 5/16 inch per foot or 0.026 in/in which is ~1.5 degrees.
KL
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@KurtLaughlin
Darn! I really messed up by removing that angle on the BM kit. Probably one of only a handful of things correct on that upper hull and I made it wrong 
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Thank you for settling this matter 
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Kurt,
What was the angle on the rear of small hatch hulls?
At least the hull is now consistently wrong
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it’s never wrong now its a “what if” tank
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Is that Audie Murphy on that .50?
Famous scene.
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