First and Third Projection Symbols

Home Model Engine Machinist Forum

Help Support Home Model Engine Machinist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
...snip that any supplier of drawings needs to agree on and standardize the conventions that will be used in that environment and/or for a client that wants it a certain way.

The wonderful thing about "standards" is that there are so many to chose from!


  • FettGrins.gif
    2 KB · Views: 0
That jogged the memory a little- had a rummage in the cupboard- and sure enough, my HP35 and HP11C are still there. The 11C still turns on (batteries must be close to 30 years old now....) but no battery pack or psu for the '35 any more.

So I had a bit of a play with the 11c- just enough to convince myself I can't remember reverse polish notation any more!

And then I removed those 30 year old batteries- thanks for the reminder Willray.
Nice to have one still working. I think the one I had was a 33E. I reluctantly gave up on it after it had to be sent back several times for a faulty power slide switch. I found a good landing involved free fall until the last possible moment and then full retro.
Hello everyone

I also have three “calculating machines” here, two from around 1975 and one earlier.
All three are still fully functional.
Commodore GL-996R (left side)
Commodore GL-987R (right side)

(The data entry also works well.)

Best regards


Still “old school” inside.

Last edited:
LOL, those Commodores are really getting back early in the hand calculator era.

And one of those dreaded slide rules in one of your photos.
I entered college when they were still teaching the slide rule (1976).
It scared me so bad that I quit college for two years, and worked odd jobs.
I tried again after two years, and the dreaded slide rule was gone, and they had gone to hand calculators.
"This I can do" I told to the teacher.

I never could master the slide rule, but most of the folks I worked with had one hanging on the wall, and they could use it easily.
I had a slide rule phobia.

They also use to terrorize us with the Smith chart.
I never mastered the Smith chart either.