Doozer
Titanium
- Joined
- Jul 23, 2001
- Location
- Buffalo NY
This may have been covered before, but I used the search function, and did not find too much.
I am making some steering trees (triple trees) for my dirt bike project.
Anyhow, I am making the upper and lower trees out of 6061 T6 aluminum, 1.5 X 4 X 19". The holes for the forks are 2.25". I am slitting them and installing clamp bolts to pinch the fork, like any other dirt bike or motorcycle. Being 1.5" thick, I was going to use one 1/2" allen bolt or two 3/8" allen bolts for the pinch bolts. There is more than enough meat to use one 1/2" bolt, and a 1/2" bolt is very strong. Then I was thinking two 3/8" bolts would spread the force a little better. Then I was thinking the 3/8" bolts would be easier to snap off if torqued too tight, where as the 1/2" bolts could take a lot of tightening abuse without breaking. Then I started thinking about using corse thread, as I am threading into aluminum, be it strong aluminum. I know fine threads are stronger, but easier to strip in softer materials. Thread engagment is about 1", so that is a lot. I know optimum would be fine threads with a heli-coil. But I am not fishing a heli-coil down in that deep hole. And for some reason, all my heli-coil inserts have a loose thread. I have heard using a tap eaten smaller by dipping it in nitric acid, but no. No heli-coils.
So what do you think I should use for pinch bolts on my dirt bike project?
One 1/2" corse bolt?
One 1/2" fine bolt?
Two 3/8" corse bolts?
or
Two 3/8" fine thread bolts?
Thanks for you help.
Other pics...
http://s72.photobucket.com/albums/i169/kooldoozer/?sc=1&multi=1&addtype=local&media=image
--Doozer (who wants to finish this thing by spring time), in Buffalo
I am making some steering trees (triple trees) for my dirt bike project.
Anyhow, I am making the upper and lower trees out of 6061 T6 aluminum, 1.5 X 4 X 19". The holes for the forks are 2.25". I am slitting them and installing clamp bolts to pinch the fork, like any other dirt bike or motorcycle. Being 1.5" thick, I was going to use one 1/2" allen bolt or two 3/8" allen bolts for the pinch bolts. There is more than enough meat to use one 1/2" bolt, and a 1/2" bolt is very strong. Then I was thinking two 3/8" bolts would spread the force a little better. Then I was thinking the 3/8" bolts would be easier to snap off if torqued too tight, where as the 1/2" bolts could take a lot of tightening abuse without breaking. Then I started thinking about using corse thread, as I am threading into aluminum, be it strong aluminum. I know fine threads are stronger, but easier to strip in softer materials. Thread engagment is about 1", so that is a lot. I know optimum would be fine threads with a heli-coil. But I am not fishing a heli-coil down in that deep hole. And for some reason, all my heli-coil inserts have a loose thread. I have heard using a tap eaten smaller by dipping it in nitric acid, but no. No heli-coils.
So what do you think I should use for pinch bolts on my dirt bike project?
One 1/2" corse bolt?
One 1/2" fine bolt?
Two 3/8" corse bolts?
or
Two 3/8" fine thread bolts?
Thanks for you help.
Other pics...
http://s72.photobucket.com/albums/i169/kooldoozer/?sc=1&multi=1&addtype=local&media=image
--Doozer (who wants to finish this thing by spring time), in Buffalo