I did deburr the holes. The SSR's are mounted on a sheet of aluminum. Screws go through the mounting holes, through the aluminum sheet, and into locking nut plates which are flush riveted to the aluminum. I didn't use the thermal grease- thought about that, but the mfr's installation sheet didn't mention it. I don't imagine heat will be much of a problem for these SSRs in this application. At most, one will operate for about 10 seconds to run the motor and pressurize the "up" hydraulic side. The other SSR will do the same thing at the end of a flight, running a shorter duration to pressurize the "down" side. So, very light, infrequent use.Did you de-burr the holes that you used to mount the SSR?
Did you use thermal grease?
The general reccommendation for mounting is to use a Bellville washer. https://www.mcmaster.com/belleville-spring-washers
Still, I'll go back and see if I can find where I might have missed the need for the thermal grease, and will use it if called for.
Thanks!
Peter