lower unit bolts big twins good idea

pcrussell50

Petty Officer 1st Class
Joined
Sep 21, 2008
Messages
296
specifically for a '59 rds21b 35hp super seahorse

I was going through the lower unit gearcase and munged up the slotted screwdriver headed 1/4-20, stainless bolts. unhappy with the idea of using slotted bolts again, and no telling if they are still available or at what cost. I had an idea. I went and got some stainless bolts from arp, with a 12-point head on them. afaict, 12 point heads when used withva 12 point socket tolerate the most torque before stripping. now the trick came because the shoulders were too wide. .. I had to "turn them down", except I don't have a lathe. so here's what I did: I got a 1/4-20 turnbuckle from big orange racing supply and
just barely threaded it in. then I put it to a bench grinder, letting it turn slowly asvtue grinder whizzed away at it. voil?. perfectly round narrowed shoulders. and arp's legendary quality.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: lower unit bolts big twins good idea

If you are going to be doing much outboard work, get yourself a hand impact screwdriver. One of an outboard tech's most important tools. Then you won't be munging up the screws.
 

pcrussell50

Petty Officer 1st Class
Joined
Sep 21, 2008
Messages
296
Re: lower unit bolts big twins good idea

If you are going to be doing much outboard work, get yourself a hand impact screwdriver. One of an outboard tech's most important tools. Then you won't be munging up the screws.

Well, damn... And I even have one of those. It never occurred to me to use it. Oh well. I'm happy with my current solution as well though. We'll see if I remain so jubilant if/when I ever need to split open the gear case again.

-Peter
 

wbeaton

Commander
Joined
Jul 30, 2006
Messages
2,332
Re: lower unit bolts big twins good idea

I believe one of the reasons OMC used those slotted screws was to limit how much torque the "mechanic" put on them to avoid over-torquing. However, I always appreciate when someone tries to improve an old design. Good for you.
 
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