I looked at the bolts again.
The are 17/64" x 20 tpi. Just
a hair bigger than a 1/4" bolt.
I have a Johnson J-80 that turns
out to be the same power head as
the Johnson Model 100, so I robbed
a bolt from that for the time being.
Was the Model 100 the "Poor Man’s Model"
for 1936, and the "J" series with the water pump
the "Deluxe" model?
The unusual size screws that we sometimes encounter are due to the old American Standard screw size system where a wide range of sizes were represented by "number"sizes . Common Examples are #12-24 (.216 Dia… used on Johnson rope plate screws); #14-20 (.242 dia … easily confused with the common 1/4 – 20) ; #16-20 (.268 dia); #18-20 (.294), also be aware that these screw diameters may have been made in various pitches like 18, 20, 24 tpi.
Joe, very interesting about the bolt sizes.
Sounds like I probably have #16 x 20 bolts.
17/64" on my drill gauge = .266
and that’s very close to the .268 you mention!
I need to find a chart with all this information!
Thanks!
Bucc, what do you mean, "no #16 bolts on the net"? If you are looking to purchase, likely you will not find any these days… long obsolete stuff. Depending on your need and lack of other options like refitting for 5/16" your only option may be to see a machinist to fabricate a custom #16 fastener.
Joe B
Just meant that I found no reference to the 17/64" size,
and nothing mentioned about #16 bolts. Would have
thought someone would have mentioned this
"bolt mystery" in the last 35 years since the Net
has been popular, lol.
I’ve had said bolts offered to me from a parts motor,
but for the time being I borrowed one from a J-80
Johnson.
Also, I’m toying with the idea of ordering some
hex stock and trying to make one on the lathe for a project.
Thanks.
Making this sort of part is an excellent evening lathe project. I’ve gotten 1/2" steel hex from On-Line Metals, and made cylinder head bolts for an L-A RBM. (I had trouble finding "high head" hex bolts that look like the originals.) They came out pretty nice. The question now is whether I should leave them in acid with some steel wool for a couple of weeks to make them look like the rest of the motor…
Good luck with the project. Any motor you can get running is a good project.
Tom, I think I can make a bolt, although I’ve never tried
one yet that small. It has a 3/8" hex head with a straight
slot screwdriver slot in it. So far I don’t have anything
better than a hacksaw to make a slot.
Just curious, would some kind of slotting saw in the
lathe work on a Palmgren milling attachment to
make the slot look more professional?
I have a little Palmgren, but no slotting tools.
Thanks.
I’ve successfully used a milling attachment and a small end mill in a collet. Take it slow. If I can do this with an Atlas 618, you can probably do it with a real lathe.
Of course using one from another motor makes a lot more sense at this point.
I didn’t even know that made end mills small enough for
a screwdriver slot. My chuck wouldn’t grab one that small,
but I’m sure there’s a "work around".
Is the Atlas 618 like the little Sears 101. six inch lathe?
My dad bought one new in the 1960’s. It’s sitting my
garage, seeing little use, as my 1950’s Logan is much
handier.
The bolt still sounds like a fun project, so I’ll have
to get the material and tooling I need to try it this winter.
Thanks!
.
.