10’ Dempster #15

[CTXmiller]

I took down my 10’ Dempster #15 a month or more back as it was leaking oil at shaft seal. There is nothing simple about working on a Dempster and it’s proving true on this one.

The key for the spider hub was stubborn. I tried a few things and those basic efforts failed. Ended up welding a slide hammer to the key and broke part of the key off after a few throws of the slide hammer. Next attempt was drill and tapped a hole in the key and used a grade 8 bolt threaded about 1/2” or more into key. The slide hammer then convinced the key to come out.

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I had a heck of a time getting the spider hub off as I was cautious not to break anything. Heated the hub damn hot on several occasions and nada, no movement. I was scared to put much pressure with a hub puller on the spider hub. Dan B’s advice was very helpful: pinning the crank plate (the #15 is a direct stroke), a large pipe wrench, a cheater bar, hell of a lot of heat and the hub started to rotate on the shaft. Rotating the hub on the shaft was success as it came off fairly easy afterwards. Finding a way to clamp the gearbox in a vise was a struggle to where I could pin the crank plate and not break anything, nor break the chain vise. The hub ultimately came off undamaged.

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Felt washer

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The bearings are good. I still have a few things to do. The gearbox is getting cleaned up inside and outside, a new felt washer, new snoot plate gasket, new key, new guide rods and some paint. I’ll add some cotton rope as gasket material for the bonnet lip for a better seal, upgrade the mast pipe (oil field pipe), plus I’m re-doing the platform. Still a work in progress, but I’m reminded why I dislike working on Dempsters.

[mtblah]

amen !

[windybob]

I have a #15 ,an 8 foot. I never took it apart, as it was workrd over when I got it. By looking inside of it, it appears it was poured with babbitt. Don't know if some came that way, or it was converted. Not near as much inside the helmet as there is in a # 12 model.

[CTXmiller]

I cleaned a few parts. New felt washer to be installed, which is the reason for the partial rebuild.

Working on a replacement mast pipe too.

[windybob]

While you have the front end apart, you might check the oil return passage, and try to scrape the gunk out of it if possible. There might even be goo in there. Goo and gunk are common items. lol

[CTXmiller]

Windy,

I’m cleaning everything that I can, including the return for which I have limited access to.

This #15 has what I’d presume is an old style mast pipe and pullout tube and I’m working on a more modern one. I always felt the chain was a link or three too short.

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The current mast pipe has some wear and previous welding on it that I presume Roger F did when he owned it. It has held up well, but since it is down, I’m doing what I can do to fix, to make things work for a few more decades.

Bushing that started life as a shaft collar.

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[mtblah]

Windy , i made a scraper to fit the oil return trough , a hack saw blade is the perfect width and length to get inside the snout passages , thanks for the reminder professor Bob for the prompt .

[mtblah]

Michael , did you make the same pullout assmbly as an 8 ft'r ?
I also used oil field pipe , and will use you example of cut pipe to fit inside & sloted for pullout .

[CTXmiller]

Michael , did you make the same pullout assmbly as an 8 ft'r ?
I also used oil field pipe , and will use you example of cut pipe to fit inside & sloted for pullout .

Mike,

I don’t have a 8’ Dempster, but I understand the 10’ #15 is the same as the 10’ #12 or 8’ #12A as both have 2-3/8 mast pipe.

Below is what I’m pondering. The pullout pipe I have is a little smaller than the pullout swivel hole, so thus the bushing (pipe on a pipe) which I tapped for a grease zerk. I had all the pipe, but for the two shaft collars so I’m not much $ into this experiment.

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[mtblah]

I like that simple setup , thanks for the ideas .