Hasselblad Tripod Plate screw standard

Have received Hasselblad quick release plate with camera plate, which came with odd-ball mounting screw, not perfectly fitting (thread is fine).

Looking into this it appears the head of this screw is non-standard, unless someone can come back with a standard this head is made to. Thread size is 1/4" UNC, so not an issue to match the thread, but head's taper/height does not match the plate recess and as result typical screw that can be easily found, stick above th plane. Kind of usable, but I am trying to find the right thing, or confirm it is a custom head devised by Hasselblad (which is hard to believe actually, but possible). If it a custom head, than I can modify what I need to make flush and still work, even if Id prefer to avoid it.

Below is the actual screw as supplied by Hasselblad.

I think the only standard for flat head screws is the bevel angle. You just have to find a screw that has a small enough head.

if you check McMaster Carr, youll see that 82degree bevel is standard for SAE with 100 degree also available, and metric is available in 60, 90, and 100 degree, with 90 degree being the most common. Since this is 1/4-20, I'd start with an 80 degree taper. There are also different "profiles" and the "undercut profile" will ensure you don't run out of thread befors the bevel of the head is snug:

On the other hand the screw might need the short not threaded part next to the head to allow the screw to thread only into the camera and leave the adaptor free to be snugged down.

could be. I don't know what exactly is needed, but the McMaster link (one of my favorite websites) does have "partially threaded" bolts. The trick is the diameter needs to be narrower than the threads to work that way, and I don't know if they are.

For the specs on that bolt, you can consult page 39 and following in the UNB catalog.

Didn’t you get a washer and bushing with that also?

Thanks everyone, interesting input. I’ll get this figured out which standard that is and will post back here. All the leads will help.

@BrianShaw no, this was quick release adapter plate, the late model with dual spirit levels, and the camera plate was part of the set, but screw was not shown, so I got what I got, no washer/bushing. But I am happy with the deal after extra discount applied by seller for this non original screw.

And never thought of typing in UNB to dig in on my own

At first McMaster Carr lead me towards 82 degree angle, then the measurements seem to kill that idea as head height is almost as much as total depth of the plate. I have no way of measuring the taper angle, especially since differences between 82/90/100 are tiny within the overall small size of this countersink. So at this stage I am leaning towards the 100 degree taper, since that head would clearly be just under flush with surface. Additionally 100 degree taper would provide more grip with large contact area.

Then the top diameter of countersink in the plate is 0.480" and MMC head size is still same for 82 and 100 at 0.531", so neither is right. UNBRAKO seems to be showing exact same head dimensions as MMC.

To recap plate itself:

• thickness 0.1665" / 4.23 mm
• top of taper 0.480" / 12.19 mm
• taper depth ~ 0.110" / 2.81 mm (this should be roughly max height of the head)

Original screw clearly made by UNBRAKO. It also appears as forged type. Search continues. The plate is usable with screw it came with, so not end of the world, but this got me intrigued and need to find the answer. I may contact Unbrako and see if they recall any Hasselblad deal, although I seriously doubt that. But hopefully they can identify what that picture alludes to.

What would help though, anyone who does have this plate with original screw, to revert with maybe photos once mounted on camera, is it flush with plate, just under, or sticks out above slightly ? Screw head dimensions (diameter and depth) ? Anyone?

I can totally relate to your desire for the proper bolt, whether the one you have works or not. I engage in the same kind of obscure quests at time too. I'll bet that it is a standard item and contacting Unbrako with the dimensions and picture of the application would yield an answer. Folks like that know their product line well, wheter they remember supplying Hasselbald or not, and tend to be very responsive even to requests for information such as this. I'd even bet that they would be willing to send you a sample that will fit. Not sure where Hassasstan is located and suggest you contact whichever Unbrako unit is closest.

BrianShaw said:

I can totally relate to your desire for the proper bolt, whether the one you have works or not. I engage in the same kind of obscure quests at time too. I'll bet that it is a standard item and contacting Unbrako with the dimensions and picture of the application would yield an answer. Folks like that know their product line well, wheter they remember supplying Hasselbald or not, and tend to be very responsive even to requests for information such as this. I'd even bet that they would be willing to send you a sample that will fit. Not sure where Hassasstan is located and suggest you contact whichever Unbrako unit is closest.

Click to expand...

Email to UNB was sent some hours ago. Time will tell, hopefully next week they will have figured it out