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Radio Mount spacer block
Posted: Wed Jun 27, 2012 9:47 am
by wesk
Can someone with one of these post the measurements I have listed?
Full size at:
http://willysmjeeps.com/v2/modules/gall ... nsions.jpg
Full size at:
http://willysmjeeps.com/v2/modules/gall ... nsions.jpg
Dia. 1
Dia. 2
Dia. 3
Dia. 4
Dia. 5
Dia. 6
Dia. 7
Countersink depth
Depth B
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
Posted: Wed Jun 27, 2012 5:22 pm
by DFoley
I have a set of blocks made by Rod....is that good enough, or are you looking for measurements from an original 1950's spacer block?
I would think that Rod himself would be able to provide the best measurements from his blocks, since he made them.
Posted: Wed Jun 27, 2012 10:32 pm
by wesk
I asked Rod several years ago if he was making them from the original drawing or from a sample and never got an answer. I have been looking for the original drawing for 6 years. I prefer to have a GI issue original for this set of dimensions and then I plan to build a new SC-C 28600 drawing from that. Our web site offers all tech data free of charge to it's members and they can use that data anyway they please. So the only answer to this lack of an original drawing is to reverse engineer an original block.
Posted: Wed Jun 27, 2012 11:10 pm
by DFoley
Ok...I'm going to be installing my radio and "modern" spacer blocks on my jeep within the next 4-5 days. So after that it's obviously going to be very difficult to get most of the measurements your are requesting. Seeing as how these spacer blocks are naturally biodegradable, what do you think your chances of finding someone with original wooden spacers are? I would think it's going to be next to impossible. I've never heard of anyone having original spacers or anybody who has ever even seen original spacers. Actually using the bottom of the MT-299 (mounting feet) and it hole locations and the geometry of the jeep wheel well itself may be your best bet.
Posted: Thu Jun 28, 2012 1:54 am
by wesk
Take a close look at the photos I posted. That is an NOS block that was in Luis' hand May 2011. They are out there. Just like the hundreds of bumper reinforcements that have survived over 50 years. My goal is not to get a pair of blocks built. It is to get a copy of the original Signal Corp drawings SC-C-28600 and 601 to complete my collection which has all the M38/M38A1 radio installation support block drawings except those two. Until the elusive original drawings show up I want to produce my own reproduction drawing using the most accurate measurements I can find off an original block.
http://www.willysmjeeps.com/v2/modules. ... _album.php
For the benefit of any member who only wishes to fabricate his own blocks I welcome your measurements and will put them up on the site for that purpose.
Posted: Thu Jun 28, 2012 5:44 am
by whydahdvr
Wes, you may have tried this already but have you reached out to the US Army Signal Corps itself to see what they have in their archives? Also, the National Army National Guard Museum might be another potential source.
If you already have then.... A wooden block would easily survive 50+ years, depending on its environment.
Posted: Thu Jun 28, 2012 8:02 am
by wesk
I've already been to the Ft Gordon Signal Site. I'll try the NG museum.
Posted: Thu Jun 28, 2012 7:27 pm
by DFoley
OK...I have taken several measurements from the wooden spacer blocks I purchased from Rod several years ago. In general appearance they seem to be nearly identical to the pictures of NOS wooden spacer blocks posted by Wes. I hope this helps.
There are two files within in my Google Docs folder...the link is below.
https://docs.google.com/folder/d/0B3IqG ... QyZW8/edit
Later,
Dan
Posted: Thu Jun 28, 2012 11:35 pm
by wesk
Dan,
Here's your photos loaded on your Mjeeps album:

Posted: Fri Jun 29, 2012 12:04 am
by DFoley
Thanks Wes...I should have put them there myself all along. I don't know what I was thinking.
A note regarding the measurements...you will notice that a few of the measurements have rather small fractional amounts (ie. 1/8 or 1/16, 7/8, 7/16). I'm inclined to believe that these represent small measurement errors during the manufacturing of these specific blocks. I attempted to be very acurate in describing exactly how my specific blocks were constructed. Most of the other measurements are in incriments of a whole inch or 1/4, 1/2, or 3/4 of an inch. It just doesn't make sense that such precise measurements would be required for this particular part. I have not actually tried to attach these blocks to my MT-299 yet...I'll let you know how they fit and if those apparent small discrepancies make any difference.
Posted: Wed Aug 28, 2013 3:30 pm
by wilfreeman
Alright - I'm making a little progress now. I bought a deuce and a half, so I have 2 projects going on at the same time. I got my red oak blocks cut and I laid the measurements off according to the drawings above. I saw where the measurements should be adjusted to my mount legs, but I wanted to double check a couple of things before I started drilling.
First, according to the measurements, the blocks are 14" long. The mount is only about 12". Do I cut the blocks to the length of the mount? The pictures that I have found don't show any wood sticking out past the mount, so I'm guessing this is what I need to do.
Second, the holes in the drawing are nowhere close to my mount holes. Mine are less than an inch apart.

So, do I use all 4 of them or only the 2 closest to the middle?
The other measurements and wheelwell channels are close enough to use as is.
Thanks,
Posted: Thu Aug 29, 2013 6:35 am
by OKCM38CDN
If I remember correctly the blocks go all the way to the side of the jeep inside and this is the extra 2" between the blocks and the mount... the mount lines up with the front of the blocks into the jeep...
The mount will hang over the fender into the passenger compartment about 2-4 inches... I do not have my M-38 handy, till the weekend. Will look at it then...
Hope this helps...
Posted: Thu Aug 29, 2013 6:22 pm
by circleburner12
hal is correct,anyway that is the way I have mind. after asking a lot of ? and research.
Posted: Thu Jun 23, 2016 10:33 am
by wesk
I know this reply is a bit late but I'll put it here to make sure it offers accurate help if someone tries to use it,
I got my red oak blocks cut and I laid the measurements off according to the drawings above. I saw where the measurements should be adjusted to my mount legs, but I wanted to double check a couple of things before I started drilling.
First, according to the measurements, the blocks are 14" long. The mount is only about 12". Do I cut the blocks to the length of the mount? The pictures that I have found don't show any wood sticking out past the mount, so I'm guessing this is what I need to do.
Second, the holes in the drawing are nowhere close to my mount holes. Mine are less than an inch apart.
The 2" extra projects from the back of the mount to the side wall of the jeep.
You will have to mate the wood spacers to the metal legs of your mount which may differ from the expected 299 mount leg.
Posted: Wed Jun 10, 2020 12:01 pm
by alexandrewillys51
Hi Wes,
I made a drawing that was excellent, I can send you by e-mail, and you can make it available for the entire forum if you want.
If this is going to help, I would be happy to provide it.
Alexandre