for shorter times...?

I got Carpal in one hand/arm from trying to put a 'spline' for a screen door into the frame...Got it w/in three hours...Direct Cause/effect...direct diagnosis after 2 months of 'rest' then test... The carpal didn't help 'clarify' the PN issue other than the fact that the PN was worse on the other side?

I DO know that total 'strangeness'...but other than Do NOT do that? I really cannot offer any sound advice other than to do it in very short 'bits', stopping before any potential buzz-nervewise or other can happen...that for me is about less than 5 minutes every 2 hours...doing anything really worthwhile [aka: showing work] is a bit frustrating?

I USED to sand by machine and hand for HOURS...those days are definitely shortened...I'd like continued use of what I've left thanks? - j