

I like the look of the spanner bolts on T-152. I didn't own a metal
lathe when took on this project, so I went to my trusty hardware store
and bought some 3/8" stove bolts ("A", at left). 1/2"
bolts will give a bigger head if you want.
B) I chucked them upside down in my drill press and, while the bolt was turning,
filed off the grade numbers and galvanized surface so they would take bluing
or Parkerizing.
C) I turned them right side up and center punched, then drilled a 13/64"
hole for a 1/4" - 20 tap. There is a convenient square shoulder on a
stove bolt that holds it nicely while tapping. After tapping the holes I cut
the heads off the shanks.
D) I threaded one end of a 1/4" rod (you can save time and buy threaded
rod) and then I screwed the heads on upside down and clamped them in a vise
in preparation for drilling the small tightening holes. For a spacer I used
the bushing I later used for the trigger roller. Once the hole was started
I removed the spacer. (I tried drilling from the arched top of the bolts with
predictable messy results. Drill from the back)
I threaded my own rod because I could, but dies are expensive.
Threaded rod is cheap and will work fine. To get the smooth top bolt I simply
screwed on a bolt head about a half turn shy of flush and then welded it in
place. I chucked it up again and filed as in "B", above, left.
The bottom heads I left open. I drilled a 1/4"
hole in the top bracket so the rod would pass through, but I drilled a 13/64"
hole in the bottom bracket and tapped it 1/4" X 20. That way the nut
is a lock nut, and keeps the whole bolt assembly from turning so the top holes
stay neatly in line.
Here (left) is a variation. A long 1/2" carriage bolt (I use a 12" bolt to get the long shoulder needed) is altered by removing the square shoulder with a metal lathe, cutting the bolt to length, then drilling and tapping a 1/4" hole in the bottom. A second, short carriage bolt is turned to 1/4" and threaded. This drawing shows the resin handle with an Allen screw keeping the handle from rotating. To see more details on making this type of bolt, click here.

Here
is a drawing of the spanner bolts if you would like to take the extra time to
thread the shank. 