3/8 inch tripod screw or adapter to metric thread screw

[MEPER]

I have a tripod head which has mount for 3/8 inch screw and I want to secure this head on a 25mm thick wood board (I want to build a DIY macro setup). To secure the head I need an approx. 40mm long 3/8 inch tripod screw with just a flat head I can secure using a normal screw driver or if an adapter exist that converts the 3/8 thread in the tripod head to metric thread (e.g. M4 (in order to use a normal M4 screw). I have a lot of 3/8 to 1/4 adapters so it is not that I am after (as I dont' have a long 1/4 thread screw). It seems most 3/8 screws are on the short side. If I knew the exact specification of the 3/8 thread for tripod heads ect....I could search for such a screw and not mention "tripod" etc. in the google search as doing this all these short screws shows up which are for another purpose than I am after.......

[Hugh_3170]

The 1/4" thread is Whitworth, but that is very close to NSC.  Pretty sure its the same for the 3/8" one.  If you have access to a lathe it would be easy enough to turn up a 3/8" to M4 adapter.

[MEPER]

It seems the 1/4 thread is close to M6 and I have M6 screws and I think I could force a M6 screw through a 3/8 - 1/4 adapter or I have a thread cutting tool also.
A M6 screw goes almost all the way through the adapter before it "bites"....
So a good idea to try such an approach.......to force an 3/8" - 1/4" adapter to an 3/8" - M6 adapter :-) 

[MEPER]

I think problem is solved. I looked what I had laying around of large screws and I had some that fit. It was pure luck. Normally I only have metric screws.
But the one I found fits nicely in the 3/8 inch thread in the head. So good I did not trashed those screws during last "clean-up"......

[Hugh_3170]

Given that you have a 3/8" to 1/4" adapter,  just get a 1/4" Imperial thread screw (20tpi pitch) from your hardware shop.  Then there is no need to force the M6.

[MEPER]

"Imperial thread screw" ....I will remember that.
Now I was lucky to find a 3/8" screw that just fits......which was pure luck.....sometimes you are lucky.....
Some screws from my fathers time. They can be 50 years old......or more......

[Akira]

Are you trying to make something like this?

Maybe you can just drill a stepped hole so that the screw head can go deeper into the board?

[Bent Hjarbo]

When the shops are allowed to open this shop can help with all sorts of weird material.
https://romerdal.dk/
Vester Voldgade 110 Copenhagen. They did help me with a similar problem.

[MEPER]

Are you trying to make something like this?

Maybe you can just drill a stepped hole so that the screw head can go deeper into the board?

Yes, exactly something like this. I am just using a 25mm MDF board. I have some heavy rubber feet's I will put on. Then there is space for the screw head.
So it is a kind of "vertical" repro setup. Maybe not exactly like that as I think there is a bit more freedom in the "vertical" solution.
For large magnification it is good if object can't move relative to lens.
The setup I usually used was camera on a tripod and object on a table. Then my weight on the floor.....just the slightest movement caused the object to go "out of focus".....or shake during exposure.

[MEPER]

When the shops are allowed to open this shop can help with all sorts of weird material.
https://romerdal.dk/
Vester Voldgade 110 Copenhagen. They did help me with a similar problem.

Thank you. Will remember this.
A 25mm aluminium or steel plate will enhance the stiffness of such a setup.....
It could be nice with a cellar with concrete floor........for extreme macro.....more difficult in an apartment.....

[MEPER]

Now I have something I can start playing with.......

[Akira]

Now I have something I can start playing with.......

I made mine as a heavy low-level "tripod" rather than the set up for the high-magnification.  Yours look promising for your purpose.