Posts: 185
Threads: 20
Joined: Apr 2007
Quote:
I would need to know the exact dimensions of the screws (diam., length) inside the HP-35 battery compartment. In my 35 one screw is missing, the other got replaced by a silver color screw in an apparent attempt by a previous owner. I do not want to remove resp. destroy the intact backside label to check with the remaning screws. I hope to get such screws as spare part, although I live in the metric world....
Thanks & regards,
Andreas
If one screw is missing, I'd probably lift up one of the feet and unscrew the one from there and move it to the battery compartment. I doubt the calculator will notice the one under the feet missing.
Or I'd take the screw to the largest nearby hardware store and try to match it with what they have. I matched a HP-97 screw very closely in the wood screws section.
Posts: 1,665
Threads: 142
Joined: Jan 2009
First, these are self-tapping screws and not machine screws. They tap the threads into the plastic posts in the case when they are first installed at the factory. I measured a few with a digital caliper, and they are approximately 7.2mm long and 2.2mm diameter. The thread pitch is very approximately 0.8mm, but I don't have a proper pitch gauge to measure this. The replacement screw may be bigger, in which case the original screw will no longer be a tight fit. I fixed this in one calc that had been previously opened by using a longer screw to make some new deeper threads.
Regards,
Michael