Help with tow hitch plunger

[Dale Jordan]

I've machined up a new plunger pin from Jeepdraws drawings . I just need some help from someone else on how they held the inside part of the 3/8 rod to bend the outer part at 90% as I can't get it into my bench vice also how hot to heat it ?? Dale

[Ben Dover]

Heat the rod red hot at the precise point you want to bend it. Slip a small length of pipe over it as leverage to bend it. Takes half a minute.

[Dale Jordan]

So you don't clamp the inside of the bend just hold it out from the casting ? Dale

[Chuck Lutz]

Joel's got it correct.....the spring on the shaft holds the plunger in one of the holes in the Landing Leg Bracket and by pulling on the end, you move the plunger out of the way so the LLB can pivot to the position you want. With that in mind, hold the Drawbar Bracket with the Landing Leg Bracket removed upside down and move the pin/plunger/spring assembly back and forth to note the travel that must be allowed for it to function properly.

When you let go of the pin so the plunger goes back in through the opening where the LLB would be if it was installed...you can now see where you need to hear/bend the pin to keept it from going back OUT the other side.

FYI...my trailer pin has 1/2" of exposed pin before the 90' bend...

[Ben Dover]

The Plunger rests against a 1/4" X 3/4" coarse thread screw" which acts as a stop. Sometimes this screw is missing or broken off. The Set Screw is located at the extreme RH side of the bore for the plunger.

[Dale Jordan]

I was wondering what that hole was for . If you look at the top photo you can see the hole on the left side for that set screw to go in , and yes it is broken off . I'll drill and tap that first I did have my plunger set at about half way through the outer hole and the same the other side and marked the bend point . so what you guys are saying is if i have the set screw in place for the plunger to sit up against like Chuck tells us the bend is 1/2 inch out side the casting ? Dale

[Ben Dover]

1/2 to 1", these were all bent after installation and they will vary a bit. You need room to grip the handle end of the plunger.

[Jon]

Dale,
The instructions are with the drawing......

"This is the bend point. Mark the rod. Pull the
3/8" end through, clamp the rod when it's fully
withdrawn. Heat the marked point and bend
down 90 degrees. Cool the rod before
allowing it to retract into the housing."

Maybe I should do a sketch and add it to the drawing.

[Dale Jordan]

I've now taped the hole for the stop bolt all works well .. Now I can heat and bend the handle Thanks Jon .. Dale

[Jon]

The Plunger rests against a 1/4" X 3/4" coarse thread screw" which acts as a stop. Sometimes this screw is missing or broken off. The Set Screw is located at the extreme RH side of the bore for the plunger.

You sure about the coarse thread Joel ?
Dale.........And I think it's a SET screw, not a a machine thread screw as shown. I'm not 100% sure tho'.
Chuck !. what do you think ?

JR

[Chuck Lutz]

Set screw....1/4-20 national fine....3/4" long.

[Jon]

Thanks Chuck. I figured as much......

JR

[Ben Dover]

Yes I am sure about that Coarse Thread , and yes it is a "Set" Screw, most Set Screws are coarse thread, (Fine does exist) this one is a "socket head".

I did not mention the type as I was indicating that a screw was located at the opposite end of the plunger bore as a "stop" for the plunger to rest on. The Set Screw is WO-53035, Bantam No. 62X2 and Ord No. 102379 AKA as a Bolt in some SNL's. I was going by memory as my Trailer Manuals were in another room.

FYI,
1/4-20 = NC Thread
1/4-28 = NF Thread
The similar casting on the M-100 also has the same coarse thread 3/4" Allen Head Set Screw that acts as a stop for the plunger.

And Uncle Sam's Army trained me to be a Machinist at APG exactly 50 years ago.

Sorry Chuckie :wink: It's very easy to arrive at 1/4-20 as being fine Thread due to the number 20 sounding like a lot of threads.

[Jon]

I think we need a photo of an original so we're all on the same page here.

The SNL for the Trailer notes it as a NF set screw, OK, we know that 20NF doesn't exist, and yes Joel, I've had a Caxton's Engineers Handbook since 1965, and I've been a tradesman since so I know my onions in this department too.
The SNL doesn't list it as a Socket type. Socket types are not full threaded, but then again, maybe that stops it disappearing into the hole.

[lucakiki]

Jon,just to be sure,what would be wrong for the normal average guy in following exactly what the manual lists?