Aermotor mast straightening

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bobceng
Posts: 23
Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Aermotor mast straightening

Post by bobceng »

Hello; my 1927 A602 Aermotor tower must have been "dropped" with it's mast in place. The "pin" is bent by about 1/4 inch from the main mast.
Anyone have experience straightening one? Is the pin swedged and welded to the mast, or threaded into it? A new, full mast for a tripod tower will probably be more expensive than a repair, if it can be done.

Thanks,all!
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Bryon
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Location: Eastman, GA

Re: Aermotor mast straightening

Post by Bryon »

Lots of heat and a big pipe wrench. If in the tower and the tower is straight-ish put string in and "X" from leg to leg at the bottom and bend the mast pipe where it attaches to the lower part (where the flat piece or oil cup is) until you see the center of the "X" in the middle of the mast pipe. The upper part of the mast pipe is "swedged" onto the lower part. Not sure what that means, but that is what I have been told.
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windybob
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Re: Aermotor mast straightening

Post by windybob »

I put them in a vise, heat it orange, and put a pipe over it to bend into shape. NOTE...Put the nut in the top of the mastpipe before bending it. If you mess up the threads, or bend the top, it's hard to fix that. The nut helps protect it.
Call Dan Benjamin for parts. P M me for the phone number.
bobceng
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Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Re: Aermotor mast straightening

Post by bobceng »

I was kind of thinking that was the way to go, but I have worked around machinery long enough to ask for advice before boogering anything up. I don't have a torch, so I will take it to a small machine/welding shop I found in Traverse City to "gitterdone" quick and right. The mast is out of the tower and only about 36" long.
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windybob
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Re: Aermotor mast straightening

Post by windybob »

Yeah, don't force-cool it.
Call Dan Benjamin for parts. P M me for the phone number.
Ron Stauffer
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Re: Aermotor mast straightening

Post by Ron Stauffer »

Not only do mast pipes bend, they also wear, crack when bent and break. Unfortunately if they crack, it is under the base cup and not readily visible. So there is inherent risk in straightening anything bent because of weakening from heating or a hairline crack. We have had 2 mast pipe failures after straightening and no longer straighten. Granted we have straightened a lot with limited issues but since decided that it makes sense to replace as dealer cost of 8' mast stem is $135. Used stems are evaluated for wear also and replaced if necessary. The last thing you want to see is a $2000+ rebuilt head come off the tower or sunflower from a mast pipe failure.

Ron Stauffer
Montrose CO
bobceng
Posts: 23
Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Re: Aermotor mast straightening

Post by bobceng »

Good point, and your actual experience makes the best sense, Ron. My tower is a tripod, and I can get the cast iron mast base off. If I could get a new mast that is threaded, I would rather save the money re-using my old three-sided base, and use the old mast as a ground "stub-mount" to hold the mill while I am working on it.

My existing mast "pin" is bent about 1/4 to 1/2"" off-center. Does that seem like a "lot" of bend to you?

Thanks!
Ron Stauffer
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Re: Aermotor mast straightening

Post by Ron Stauffer »

The definition of "a lot" is too subjective with the variables of wear and what was done to bend it.

Instruments for battle:
2 36" pipe wrenches
1 4' cheater
1 6' cheater
mast removed on a concrete floor

Attach one wrench with 4' cheater open jaw up to the narrow part of the cast base directly adjacent to the stem. Dont go on the area where the mast base bolts are as the base is cast. Stem of the mast is pointed to your right. The jaw set needs to be adjusted just right and set with a hammer. Other wrench with 6' cheater is set within an inch laterally of the other wrench and a 10 to 15 degree angle to the other backer wrench. Motors usually leak enough oil so the mast is not normally frozen but they are tight. Good luck

Ron
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windybob
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Location: Ames Oklahoma

Re: Aermotor mast straightening

Post by windybob »

I have broken the bases of mastpipes before. I try to heat them first to help. Yes, they are tight!
Call Dan Benjamin for parts. P M me for the phone number.
bobceng
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Joined: Tue Aug 25, 2020 6:28 pm
Location: Northport, Michigan

Re: Aermotor mast straightening

Post by bobceng »

The way I planned to salvage the base from the mast: hacksaw across the bottom of the mast right where it meets the cast base. Separate the base and mast. Take a hack blade in a poke saw or gripped by a vise grip. Make two cuts across the 1" of mast material threaded into the cast base, then gently use a cold chisel to collapse the old mast material loose from the casting threads. No risk of damaging the cast base, and the old mast is being "junked" anyway.

We used this procedure to remove steam and water pipes where we needed to preserve the fittings they were stuck in. If you went easy, the connection didn't leak after the repair was completed.
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