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  #1  
Old 05-19-2017, 01:14 AM
crystallographic crystallographic is offline
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Default Campbell 2536 Nibbling Machine rebuild

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This machine got dragged to my storage area in 1984. The shaft was seized so it sat in the weather for 30 years, to season up a bit.
P1160017 copy.jpg
In 2014 I soaked the 3inch bronze plane bearings for a month with a mix of 50% acetone and 50% ATF (flavor unimportant) with 90psi compressed air force-feeding the oil charges. After 29 days the oil mix began seeping out of the bearings, so I kept force-feeding until I was getting a good flow and hissing from the bearing ends.
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End of 3inch main shaft with eccentric shown. Bearing end would hiss and flow dirty oil mix. (Note that the up-down mechanism has been removed to show the end of the shaft.)
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4 foot lever arm is bolted to drive sheave w/2ea. 3/4inch bolts and screw jack is applied to lift arm/turn shaft. (Barely visible are two air fittings, one at each end of the frame, which feed air and penetrant down into the oil galleys in the two main bearings.)
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Close-up shows screw jack w/1/2inch drive impact socket welded onto input and 1/2inch drive impact gun is used to raise and lower jack, encouraging lever to loosen shaft.

Slow going for a few hours, during which time penetrant additions and forward-reverse efforts on jack slowly get shaft to turn one full inch.

At this time the previous owner shows up and mentions that this nibbler fell off of a flat bed truck when he was moving it, so many years previous.
This explains why the shaft is so stubborn and why the road rash exists on the motor housing and two corners of the frame.
I'm not worried about the frame because it is solid flame-cut plate, 5 inches thick. (MFG date = 1957, post-war "build it to last forever" thinking.)
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I get a strong young lad with cheater bar to grunt on the shaft for a few more hours, getting the shaft to move 90deg, and then 170 deg, back and forth. Now I think the shaft is bent.
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Pullers are never big enough so I make one and start dragging the (custom-by-crash) drive sheave off the shaft end.
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Since that gets the sheave off, I move to the front and shove on the shaft.
Some 1" round 4340 TGandP works as a roller bearing for the shaft to retreat.
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Shaft retreats and also takes the rear bearing free. A nice plus. Then the vertically-applied flame thrower helped expand/loosen the bearing a wee tiny helpful bit so I could slip that off the shaft end.
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Some cleanup at the machine shop will leave both the shaft and both bearings in nice re-useable condition. Another nice plus.

Next up: going through the business end of the main shaft.
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Last edited by crystallographic; 05-19-2017 at 09:07 AM.
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  #2  
Old 05-19-2017, 02:10 AM
longyard longyard is offline
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Nice write up Kent. I felt your pain! I'm looking forward to Part II.
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  #3  
Old 05-19-2017, 08:57 AM
cliffrod cliffrod is offline
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Big things falling off a truck. Sitting around outside for decades before anything is done. Giant cheater bars. Challenging a young superman to move what can't be moved. Sounds like things around here. Cool to see it coming apart well for you. That's usually the only thing that happens differently here......

Nice to see old equipment being brought back to life. Thanks for posting, Kent.
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Old 05-19-2017, 09:28 AM
galooph galooph is offline
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Patience really does pay off when it comes to acetone/ATF mix! You did really well getting that apart, given its history
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Old 05-19-2017, 04:27 PM
ojh ojh is offline
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How did he phrase that..'oh jeez, I just remembered, this thing fell off the back of the...' He must be from around here.
This is going to be good, we'll need lots of pictures.
Whats your plans, use it as a nibbler?
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Old 05-19-2017, 04:56 PM
Gareth Davies Gareth Davies is offline
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Wow, 33 years taken just to start a project! There's hope for me yet.
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Old 05-20-2017, 01:10 PM
crystallographic crystallographic is offline
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Thanks, Bill. Fortunately there were no injuries and the pain of it taking 2 years of step-by-step hurdle-solving was indeed testing my patience.

Yes Cliffrod, this was a semi-planned process that took its own course, with my guidance sifting out the "gotta get'er done" hubub. You are very welcome. I thought it might present a helpful view, rather than the alternative / helpless one...?

Hey thanks, Galooph. (I had actually soaked it with the udder stuff for a year prior with zero encouraging signs --- -- edited out for a smoother tale. )
And - I'm in no rush to hurry to the scrapyard - or to make new parts.

Yes OJ, when I heard that it would do 1/4" stainless I got more enthusiastic - since my other cutters (excluding plasma) reach their limits at 1/8" stainless. More pix are indeed coming and hoping they are detailed enough to help anyone either not having all the parts needed, or having the right parts in a dirty rusty heap.

Gareth, it's not that hopeless, actually. It was only 30 years to start soaking the seizures and then two years to gently nudge the bits apart, clean, inspect, rework, weld the shattered iron, and then assemble and check everything twice --- and then hit the switch to hear the hummmm-click-click-click of a really nice solid old machine.

---- And then another year to fine-tune and get replacement punches and dies and start painting the beast. (Of course a heart procedure and a tough car wreck did vacuum some hours from that 3 year home stretch .... )

... the story continues ....
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Old 05-20-2017, 01:55 PM
crystallographic crystallographic is offline
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Default PART 2 - Rebuilding the Campbell 2536 - 6 nibbling machine

After nudging out the bearings I took them and the 6foot x 3inch main shaft over to my excellent machinists - Milo and his son, Doug.
001 P1160020_jpg.jpg
(Milo ran a crew of 35 machinists for Schrillo Co. during WW2 and then started a little racing parts company later on, in the 1950's with his buddy Don = Milodon - look them up on the Milodon homepage.)

Doug lined the shaft out in the big lathe and found no runout = not bent, so he cleaned up the bearing surfaces and had a look at the bearings. The rear one was a bit out-of-round so he trued it up, cleaned them both and fit them back onto the shaft - with very nice clearances.

Time for the flamethrower to open up the holes in the frame.
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And quickly push in the bearings....
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Some scuffing was left in to keep the fit ... nice fits.
And the shaft went right on in - so the frame was still true.

Right side of machine shows business end unassembled and electric controls at rear.
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Original electrics ... so the bug nests were cleaned out and the contacts brightened with crocus cloth.
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7.5V heaters (fuses) were found to be accurate - 3ea.
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Motor is 2hp 3ph. Oh, did that have a story to tell .... but more on that, later.

Back to the frame and mechanism... larger oil cups were added -
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but I have yet to find 3/8" round wicking ... help?
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Shaft eccentric rotates inside bronze block which in turn raises and lowers upper steel sliding block.
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Upper block is coupled to lower plunger /collet by a fork, riding up/down all the time machine is running - except when the fork is pulled out, disengaging the lower plunger. This was so the nibbled part can be moved/repositioned and then the mechanism re-engaged to proceed with nibbling within another enclosed area or just to remove the part.

End of Part 2.
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Last edited by crystallographic; 05-20-2017 at 02:02 PM.
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  #9  
Old 05-20-2017, 02:51 PM
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mr.c mr.c is offline
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So it is a scotch yoke mechanism (the bronze block). How was the wear on those pieces?
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Old 05-20-2017, 06:04 PM
crystallographic crystallographic is offline
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Quote:
Originally Posted by mr.c View Post
So it is a scotch yoke mechanism (the bronze block). How was the wear on those pieces?
Yup.
It was the lack of wear on the yoke that inspired my taking it all the way down.
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