Author Topic: Getting mean with Gibb keys  (Read 1125 times)

38ac

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Getting mean with Gibb keys
« on: April 29, 2023, 01:39:04 PM »
Lister VA in the shop with typical ex Amish owned problems includinging both Gibb keys having the heads broken off. At least they quit this time instead of ruining the flywheels.
« Last Edit: April 29, 2023, 02:04:57 PM by 38ac »
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38ac

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Re: Getting mean with Gibb keys
« Reply #1 on: April 29, 2023, 01:43:50 PM »
The tools used for the shock treatment. After placing a good pull on the key the hub gets a big whack with the 8 Lb sledge and pin with a handle welded on.  The key then pulls out.
« Last Edit: April 29, 2023, 05:36:42 PM by 38ac »
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38ac

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Re: Getting mean with Gibb keys
« Reply #2 on: April 29, 2023, 01:58:23 PM »
On to stuck flwheels.
Spray some snake oils on if it makes you feel good but 19 years later they will still be stuck.  12 tons pulling and couple solid whacks on the back side and this one moved, NOW spray some snake oil and it will do some good.  Often times heat is needed but not on this one. Photo won't pass security for unknown reasons so imagination is required ;D

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ajaffa1

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Re: Getting mean with Gibb keys
« Reply #3 on: April 29, 2023, 10:42:37 PM »
Nice work as always. The Amish are renowned for their carpentry not their engineering skills. I`ve often wondered why Lister didn`t specify a Gibb key with a bit more meat in the head. Will you be replacing the Gibb keys with Indian copies? The last set I ordered had the wrong taper and had to be filed to fit, they also don`t have the milled slot down the middle.

I`ve had trouble posting pics in the past, check the camera resolution, if the file is too big it will get rejected.

Bob

38ac

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Re: Getting mean with Gibb keys
« Reply #4 on: April 29, 2023, 11:18:53 PM »
Thanks Bob, The files have all been reduced to proper size. The error messag states that it won't pass security checks ??? Gibb keys must be made in several shacks because there are at least 5 designs from India. Some are right, some not.
« Last Edit: April 29, 2023, 11:22:45 PM by 38ac »
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cobbadog

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Re: Getting mean with Gibb keys
« Reply #5 on: April 30, 2023, 07:08:06 AM »
I did my apprenticeship at removing broken Gibb Head keys from the McDonald Super Imperial Crude Oil engine I did up not too long ago. Both sides had broken heads and were also broken off flush to the flywheel. So spent the next 2 days drilling out the metal using 1/8" diameter drill bits. Had a stuff up when one bit bottomed out on a taper on the crankshaft I was unaware of so that snapped off inside too. It was a true challenge to get these buggas out but I did win eventually. Then spent a bit of time using wet n dry paper polishing the crankshaft so when or iff the flywheel was going to move and come off there was no rust to hold it back. So with a hydraulic puller, a lot of tension and then heat they finally came off. Total time spent removing 2 flywheels was close to 2 weeks, a lot of skin off the knuckles, a hell of a lot of swearing and an ongoing apology to neighbours for my language. So I do feel your pain on this topic.
As for Gibb Head keys, yes there are many different sizes but now not all are made. Engine manufacturers used these keys because they did the job and were cheap to buy in at the time. My McDonald has odd size keys so had to mill them down in height. I am not a machinist but a mate offered me the use of his mill so no time like now to learn. I lost hours of sleep working out how to machine these down and keep the taper. The solution when it finally came to me in the middle of the night was to place both tapers together and this left the flat sides that are now parallel so was an easy milling job. In order to fit Gibb Head keys they nearly always need some filing using bearing blue to ensure the correct fit. Fortunately one needed a little drawing filing and the other was a bit more but not hard to do just messy.
38ac, where your pics of the keys 'naked'?
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broncodriver99

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Re: Getting mean with Gibb keys
« Reply #6 on: April 30, 2023, 09:48:08 AM »
Butch,

Not sure if you know of these guys but they are in Northern Kansas and have very high quality tapered gib keys as well as tapered pins, most all of them made in house, as well as all kinds of key stock and other hardware. I found them after several very dissapointing dealings with Indian pins and keys. I think there was something like a $25 minimum order. The keys do come perfectly on size for width but full thickness depth wise and have to be fit but are made of much higher quality material than the Indian keys I have had my hands on.

https://www.huyett.com/all-products/machine-key-stock-machine-keys-shafts/machine-keys/gib-head-machine-keys
« Last Edit: April 30, 2023, 09:55:47 AM by broncodriver99 »

broncodriver99

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Re: Getting mean with Gibb keys
« Reply #7 on: April 30, 2023, 10:07:47 AM »
Just dug into their site a little, haven't been there in a while. Looks like their minimums have gone up. Looks like the 9/16" keys are special order now which they weren't then.They used to have them by the each.
« Last Edit: April 30, 2023, 10:11:47 AM by broncodriver99 »

cobbadog

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Re: Getting mean with Gibb keys
« Reply #8 on: April 30, 2023, 12:14:16 PM »
The new keys I bought I believe were made in Victoria and not imported.
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38ac

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Re: Getting mean with Gibb keys
« Reply #9 on: April 30, 2023, 02:19:16 PM »
IMy McDonald has odd size keys so had to mill them down in height. I am not a machinist but a mate offered me the use of his mill so no time like now to learn. I lost hours of sleep working out how to machine these down and keep the taper. The solution when it finally came to me in the middle of the night was to place both tapers together and this left the flat sides that are now parallel so was an easy milling job.
38ac, where your pics of the keys 'naked'?

Milling set ups are also a challenge for me due to having 100 hours on a lathe for every hour on a mill.
One shop that makes the keys in India makes them too high but the taper is close to correct. I place them in the mill vise upside down and tram them in. Final fitting takes care of small errors in taper which in the case of India engines may be in the key or the flywheel.  It's a better situation than two other India shops that make keys that are too narrow and a sloppy fit in both keyways.
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