Loctit 648 information and help

[Ye-Ole Steam Dude]

648 is the loctite I use most of the time and time does vary depending on the fit of the parts but have not had problems using it on small cranks. When assembling cranks I bond the pin to the two throws first using the main shaft to keep things lined up and let that cure. Then you have a "U" shape that can be slid along the shaft as one so both joints can be bonded at the same time and you only need to set it for position along the shaft

One other thing to consider is what did you clean the parts with, some cleaners can actually accelerate the cure time.

Excellent idea on the procedure. I might take the crankshaft apart with heat, clean it real good again and try this method.

As far as cleaning, I had cleaned all the parts with alcohol several hours earlier. Just before assembly I ran over each "area" with some 1000 grit sand paper and wiped it clean with a paper towel.

Jason, thank you for this info.

Thomas

[Ye-Ole Steam Dude]

Hey again,

I know this example is not very scientific but so far I have found 648 to set up much quicker than the 680. I milled the face on a 1/4" brass round rod by .040 on both sides which is one of 2 roller valves. I cut a shape of .040 brass for a bracket that will hold the wheel. Laid the bracket flat, applied a drop of Loctite and then set one side of the 1/4" rod on the bracket. No pressure or real tight fit here.

First time I used the 680 and 20 minutes later it had not “set”. About 20 minutes later I checked and it had set.

Second valve rod, same as above but used the 648 and it set well enough in less than 2 minutes that I could lift the whole assembly as one part.

Only time will tell if after they have completely cured if there is a true bond of the two pieces and enough strength to hold all the pieces together.

I sure appreciate all the help and information from everyone.

Later,
Thomas

[Ye-Ole Steam Dude]

OK everyone,

I took apart the crankshaft using a Bernzomatic torch and to my surprise, the pieces came apart fairly easy. However, to get one lobe or one set I do not think is possible because the heat transfer along the main shaft loosened the second set.

My photos are not the best but you can see there is quite the mess left on the main shaft. I took some MEK to clean most of the crud and then used a course sanding sponge on the lobes to get back to bright brass. I put the shaft in the lathe and used a fine sanding sponge on the bottom while holding a course sponge on the top and turned the shaft at 600 rpm’s. The second photo shows how nice it turned out.

I then ran a reamer through all the holes and removed a bunch of crud from them. As you can see, it all looks as new and all the parts go back together OK.

I will try again to Loctite everything back together using Jasonb’s method. Not sure which of the two I will use, but I do plan to set the chosen one in the icebox to chill it down a bit and I will have the A/C in the shop turned down. Might wait til tonight.....

Thomas

[Ye-Ole Steam Dude]

Everything has gone so smooth that I was able to reassemble the complete crankshaft. I used Jasonb’s method and it was so quick and easy. I decided to try the 648 again but this time I placed the bottle in the refrigerator on the middle shelf for about 20 minutes. The chilled Loctite gave me an additional 10 to 20 seconds before it set up.

 I did the procedure in three steps:
First I made the “U’s” putting together two of the lobes and one 1/4" journal and clamping them flat for about 10 minutes.
Second I made a temporary jig to clamp and hold in place the first “U” (journal number one) and a backstop to stop the main shaft at the correct distance from the clamped journal. I slid the main shaft in the journal until it hit the stop and then withdrew just enough to apply the Loctite to the required area. Then I pushed and rotated the shaft until it hit the stop.
Step three, I made a second temporary fixture/backstop for journal number two and repeated the above procedure.

It all went as smooth as a river rock and I am a happy camper  and I feel like I have moved up one notch on the learning curve for using Loctite.

Hope this will help others and thanks to everyone for all your input and knowledge.

Thomas

[crueby]

Very nice, another one to file away (and hopefully remember it is in the file).