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12-17-2020, 12:02 PM | #1 |
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Depth of threads for ratchet nut?
Does anyone know offhand how deep the threaded bore is on the crankshaft for the ratchet nut?
My ratchet nut is really beat up and I've removed it – I plan to replace it with a hex bolt & Grade 8 washer that will make it easier for me to turn the engine precisely during maintenance. I know the threads are 5/8"-18, I know the ratchet nut has 7/8" of threads on it, and I can tell the bore is at least 1.5" deep, but with the engine in the car I can't see how deep the threading goes. I want to order a bolt that engages as much of the threading as possible without being so long that I can't tighten the pulley down. Do the threads go the whole 1.5" bore? Thanks in advance |
12-17-2020, 01:05 PM | #2 |
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Re: Depth of threads for ratchet nut?
You might go ahead and get a long (say 2") el cheapo Grade 5 cap screw at your local hardware store, thread it in and measure how much is left when it bottoms out. Figure the length of the Grade 8 from that before you order. Empirical engineeering.
JayJay
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12-17-2020, 01:11 PM | #3 |
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Re: Depth of threads for ratchet nut?
Based on the two crankshafts I have laying around the hole is not tapped all the way to the bottom. I was able to thread a ratchet nut all the way in so based on these two cranks you would be good at 1". Feeling into the hole with an awl I can feel the first thread at about 1 1/4" but can't tell you where the deepest full thread is. If you need to know exactly for your crank I agree with JayJay's suggestion.
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12-17-2020, 01:14 PM | #4 |
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Re: Depth of threads for ratchet nut?
I would do that, but 5/8"-18 isn't a bolt type they carry around here. Also I thought somebody on here might know, save me the trip.
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12-17-2020, 01:18 PM | #5 |
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Re: Depth of threads for ratchet nut?
Just measured two shafts. Threads go 1 1/4" in.
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12-17-2020, 01:38 PM | #6 |
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Re: Depth of threads for ratchet nut?
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12-17-2020, 02:22 PM | #7 |
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Re: Depth of threads for ratchet nut?
The pulley should be , but some reproductions are not to specifications
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12-17-2020, 02:36 PM | #8 | |
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Re: Depth of threads for ratchet nut?
Quote:
It's been very frustrating using the crank to turn the engine over up till now. Not only did the degraded ratchet nut not hold the crank very well, but my A has a flat steel piece welded on top of the front crossmember – I assume as a repair – that precludes installation of the crank guide. |
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12-17-2020, 05:28 PM | #9 |
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Re: Depth of threads for ratchet nut?
I am using a ⅝-18X1" Grade 8 bolt to for my Murray balancer. Works fine. The Murray is a bit tight for the ratchet bolt.
Why don't you want to use a new ratchet bolt? |
12-17-2020, 05:40 PM | #10 |
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Re: Depth of threads for ratchet nut?
I would not do that. But I respect that it is your car Sir.
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12-17-2020, 05:55 PM | #11 |
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Re: Depth of threads for ratchet nut?
I have the same problem with a deformed ratchet nut so the hand crank slips. What was your nut wrench size? I ordered a 1 3/8" socket and it's too small. Fits the replacement ratchet nut perfectly though.
Is there such a thing as a 1 7/16" ratchet nut? Can't get my calipers in there to take an accurate measurement. |
12-17-2020, 09:41 PM | #12 | |
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Re: Depth of threads for ratchet nut?
Quote:
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12-17-2020, 09:47 PM | #13 | |
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Re: Depth of threads for ratchet nut?
Quote:
It's a 100% reversible operation. I might go back to the ratchet nut after I've gotten the car "sorted" as they say. Or I might leave it for the next guy to do. Edit: I mean, sure, I could take a good crank guide, cut the bottom off, and weld the bushing portion onto the steel plate atop the cross-member, but I can think of a lot of reasons I might regret doing that later. |
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12-17-2020, 10:03 PM | #14 | |
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Re: Depth of threads for ratchet nut?
Quote:
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12-17-2020, 10:12 PM | #15 | |
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Re: Depth of threads for ratchet nut?
Quote:
You could also try a 35mm or 36mm socket. |
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12-17-2020, 11:03 PM | #16 |
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Re: Depth of threads for ratchet nut?
Thanks for the links.
Looking with a mirror and a flashlight, the nut looks in really good shape. What's odd is the nose of the nut is shallower, the 'hooks' the crank fit into are shallower, and have way less lip. That's allowing the crank to slip out instead of crank the engine. But the nose of the nut has a very machined look to it, not an abused look. And it's bigger than 1 3/8. A rotary tool isn't going to help here. I don't get it. |
12-17-2020, 11:23 PM | #17 | |
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Re: Depth of threads for ratchet nut?
Quote:
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12-18-2020, 01:06 AM | #18 | |
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Re: Depth of threads for ratchet nut?
Quote:
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12-18-2020, 11:16 AM | #19 |
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Re: Depth of threads for ratchet nut?
Possibly the 1-3/8" socket isn't broached deep enough?
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12-18-2020, 11:21 AM | #20 |
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Re: Depth of threads for ratchet nut?
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