Intrepid 8x10 Base Plate Modification

[Michael Kadillak]

A while back my patience was rewarded with the arrival of an 8x10 Intrepid camera. Although the ground glass was destroyed in shipment (hopefully Intrepid will add the proper padding to protect the GG in future shipments), I forged ahead with a GG replacement. My next "issue" was the fact that my 3/8" screw on the base plate of the camera was not threaded properly to accept the 3/8" Arca Swiss base plate more than two thread rotations. Not acceptable.

Further objective analysis of the situation concluded that the base plate for these 8x10 cameras was woefully too thin leaving my camera susceptible to camera rotation upon film holder insertion.

My solution was to replace the camera base plate with a nearly double thickness aluminum base plate and a machinist friend of mine took my Area Swiss base plate and added two 3/8" threaded screws to take the potential rotation of the camera upon film holder insertion completely out of the equation. Did not add much or any weight to the camera and it vastly improves the functionality of the camera. Base plate thickness is critical IMHO to accept the base plate screw and this provide an adequate platform from which to use the camera and the augmentation of the thicker base plate I feel will make a dramatic improvement in the use of this camera. The attached photos show the new base plate with the two new 3/8" threaded screws on an existing Arca Swiss base plate. I am sure that other companies that make base plates can easily also be modified to accomplish an identical objective. Onward!




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[Bob Salomon]

Somewhere or other there is a standard for the depth of a tripod screw and socket. Granted many cameras have deeper sockets, mostly view cameras that unlike 35mm and 2.25 modern cameras don’t have any electrical circuits or mechanics under the socket.
Someone should inform Intrepid if their sockets aren’t deep enough.

[Peter De Smidt]

Good solution. In my case, a Gitzo 3/8 tripod screw works fine with the Intrepid base, and since the tripod head, a Gitzo Series 3 low profile pan/tilt, completely covers the Intrepid mounting plate, there's no need for a thicker plate.

[Greg]

Plan on doing something similar on the bottom of my 11x14 Chamonix. I use a Kessler Crane Kwik Utility Plate on the bottom of the camera. The single 3/8" screw does firmly hold the Utility plate to the camera, but once it did rotate a tad bit when I was inserting a film holder (probably more from my not tightening the 3/8" screw enough). Copying this from the design of the Sinar Pan Tilt head... I plan to insert into the back of the Kessler plate is a small round SS pin/rod sticking up about an 1/8". On the bottom of the Chamonix will add a 3/8" bolt flush with the bottom of the bed and with a drilled center hole that will accept the SS pin/rod.

[Michael Kadillak]

Somewhere or other there is a standard for the depth of a tripod screw and socket. Granted many cameras have deeper sockets, mostly view cameras that unlike 35mm and 2.25 modern cameras don’t have any electrical circuits or mechanics under the socket.
Someone should inform Intrepid if their sockets aren’t deep enough.

Completely agree Bob. I expect Max with Intrepid is privy to this venue and will have the opportunity to consider this as an option. I was disappointed at the inability of my camera 3/8" threads to properly accept the quick release screw, but it was quickly remedied.

[Michael Kadillak]

Upon mounting my camera and checking it out my 8x10 Intrepid with the modified double 3/8" Arca Swiss mounting base on the thicker aluminum camera metal base plate is twice to three times as solid and "twist" resistant as what I experienced with the original single make up screw that came from the factory. Enormous difference in how this camera will function in the field that is easily ascertained by simply applying some modest side pressure analogous to inserting a film holder. Now when both of the 3/8" screws are locked down it is twist resistant as any of the four 8x10 cameras I own. IMHO this is a must for a camera that tips the scale this modestly.

[Bob Salomon]

Completely agree Bob. I expect Max with Intrepid is privy to this venue and will have the opportunity to consider this as an option. I was disappointed at the inability of my camera 3/8" threads to properly accept the quick release screw, but it was quickly remedied.

It would seem to be one of the first things that a manufacturer would determine once they mounted their first prototype to a tripod and looked at how established manufacturers mounted their cameras.

[Daniel Stone]

If you want the best "hold", you need to have a (minimum) thread LENGTH contact area equal to the width of the thread itself, ex : 1/4" = 1/4" depth, 3/8" = 3/8" depth, etc. Remember, these are MINIMUMS. A 35mm camera will likely be fine with 2-3 threads to hold it, but for MF or larger, get as much thread contact as you can. Having a larger mating(contact area) between camera and tripod head as possible, to minimize stress on the threads themselves in addition.

-Dan

[klw]

If you want the best "hold", you need to have a (minimum) thread LENGTH contact area equal to the width of the thread itself, ex : 1/4" = 1/4" depth, 3/8" = 3/8" depth, etc. Remember, these are MINIMUMS. A 35mm camera will likely be fine with 2-3 threads to hold it, but for MF or larger, get as much thread contact as you can. Having a larger mating(contact area) between camera and tripod head as possible, to minimize stress on the threads themselves in addition.

-Dan

AFAIK the maximum strength of a screw in steel is reached when the length equals the diameter. So for a 3/8" screw the maximum strength is reached when the thread is 3/8" deep.

In aluminum the maximum strength will be reached at 2.5x diameter. For a 3/8" screw this should be reached at 2,38cm.

So using a steel insert might be a good solution.

[Michael Kadillak]

But since you are adding two 3/8" screws to the base, its tensile strength requirements are less rigid in this application. A thicker aluminum piece I feel should be more than adequate.

[klw]

Of course, strong enough does not nessesarily equal maximum strength :)

[Michael Kadillak]

Of course, strong enough does not nessesarily equal maximum strength :)

True. But the camera tips the scale at 4.5# not 14# like my Toyo 810M. As a result I do not feel the need to be concerned about designing for maximum tensile strength.