willysmjeeps.com

Does anyone have the dimensions of the base plate and holes on the pedestal machine gun mount? I have seen Wes's photos and can make out any dimensions. Looking to pre-drill the holes in the body. Thank you!

I haven't seen any measurements yet. If you must work without measurements I see no reason you couldn't locate the M31 tube base accurately based on the TB ORD 465 & ORD 8 drawings and reverse engineer the three braces and supports.

Thx Wess. All good information and I appreciate your time. It's not really helping me find just the dimension of the pedestal base plate and holes, but hopefully some else has one that can supply those dimension.

Go to www.jeepdraw.com and look
up the rear section list for the WWII
Jeeps.

For a very modest fee you can purchase all
or any of the drawings you are looking for:

http://www.jeepdraw.com/rear-sect.htm

They also have a lot of other drawings and
information.

Thank you, Brian!! Just what I was looking for. Awesome.

Keep in mind that there are significant differences in the mounting position of the WWII jeep mount so the leg lengths may not come out right for you. Also the WWII mounts bolted through to the crossmember gun mount pad which the M38 does not have so you will still need correct fabrication dimensions for the under floor center reinforcement.

Also, you must account for variations from mount to mount with respect to bolt hole position. I would take the measurements straight off of your mount to make sure that they line up perfectly.

It really feels like you should build the mount first, then match
drill the tub and install the mountings to match.

Probably not what you have in mind but I bet it would
be easier in the long run to get it right.

The key is to make sure the legs end up in the correct place
for the tub if using the drawings, although I think and Wes
will correct me, if labeled correctly the mounts should be
the same, just the respective mounting equipment and so
forth would vary per vehicle.

Note there are different instructions between the M38 and A1,
based in part on the A1 having a mounting plate installed
at the factory as noted earlier.

So, per the drawings above the M38 takes the M31a1 and the
M38a1 takes the M31c.

Wonder where the difference lies? Maybe in just the mounting
and associated equipment. Who would know?

Maybe one of the current manufacturers of replica/replacement
mounts. I bet those guys have all the drawings.

Looks like these guys supply only the M31c for either the M38
or M38a1. Note there appears to be an early pedestal without
legs, but a note mentions standard four bolt pattern

Also, they list brackets further down for the two rear legs for
the M31c.

Fun stuff. Good surfing on a cold, rainy November.

Here is a third look. There is a waffled bracket under the floor, and looks to be three L shaped brackets that one could extrapolate the dimensions and thickness with the available drawings as well as the bolt specifications.
http://imageshack.com/f/11/m31a1cz3.jpg

That waffle bracket might be a little tricky.

I also ran across a G503 discussion that described the pedestal as essentially the same from WWII all the way to the M31C, with a change at some point to eliminate the travel bar. Supposedly not needed due to a redesigned reinforced pintle. The author did note however, that he observed many M31C mounts removed from National Guard M38A1's that had the travel bars. Were they dated from the 40's or just built to the original specs?

Also noted was a change in the legs to lengthen the cutout for seat frames specific to the M38.

Take care,