Is loctite alone strong enough for a crankshaft?

[David Powell]

I am building a 2 inch scale Clayton steam wagon. The crank is 1/2 inch diameter, the webs 3/8 inch wide. I have all the parts a slip fit, one to two thous clearance everywhere,. I have a brand new supply of Loctite 680, the parts are all shiny clean.
Previous unfortunate experience with Loctited parts has made me wary and I intend to pin the parts together with 1/8 diameter dowel pins once the shaft is assembled and the loctite set.
Do I really need to add the pins?
Regards David Powell.

[pat1027]

I have a Clishay with a crankshaft assembled with Loctite. No issues.

[hoppercar]

Made a couple crankshafts from solid material...the way kozo describes it in his shay book......it's quite a feat with fixturing and turning, but worked out well, scaling up to a 1 1/2 shay. ....have never built one in pieces and loctited....so I guess I'm no help there ?

[cbrew]

i would still run keys/pins
also, 1 to 2 thou is a little slim for 680.

[gwrdriver]

I've Loctited small cranks, but I always added pins.

[Odyknuck]

Will Loctite work yes, maybe. For peace of mind and the guarantee of parts not slipping, go with Loctite and pins

[Bill Shields]

Most of you know what I would do / have done many times and not had a problem.

Lots of good advice above.

I would recommend taper pins if you go that direction.

[Greg_Lewis]

The use of Loctite has generated some heated responses here in the past. IMHO, if used properly I find it works fine. However pins are cheap insurance.

Here's the data for Loctite 680:
I have two sources for gap fill, both are Loctite publications. One says the gap fill is .002, the other says .015. I think a phone call on this would be in order.
- sheer strength on steel 4000 psi.
- temperature range -65° - 300°F
- full cure 24 hrs.
- recommended primer T

[Bill Shields]

One important thing to keep in mind is that you need to have everything square as the glue sets up.

If things set up even slightly crooked, you will be attempting to flex the joint on every revolution, which can lead to a failure.

Plan ahead...even if you pin it, it's got to be square

[rrnut-2]

I built one of Kozo's first Shay in 1 1/2sc. I made the crankshaft in pieces, locktited them together and then used taper pins just to make sure. Its been running for 30 years and no problems.

Jim B

[jcbrock]

My experience is with a crank that has a 1.125" throw. Loctite 680 and taper pinned one pin per throw, the pins sheared and things came apart. Attempt #2 with 680 and woodruff keys seems good so far, but not a lot of hours yet.

[Fender]

Why not make the parts to a larger clearance, followed by a light knurling and finishing of the cylindrical components? This will give more space in the joint for the loctite, while preserving the alignment/squareness of the assembly.