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Author Topic: Crossthreaded handrails  (Read 203 times)

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girmann

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Crossthreaded handrails
« on: April 07, 2021, 09:22:25 AM »

Well, it looks like one of the PO’s cross threaded one of the bolt holes on the port side stainless hand rail. I have no idea how to fix this, other than to take it to a shop and have them redo it. I don’t have a tap and die set. If I got one, do I drill it out and make a bigger one, or can the existing threads be “reset”?

Thanks!
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Phil Spicer

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Re: Crossthreaded handrails
« Reply #1 on: April 07, 2021, 10:47:41 AM »

 You could try to re tap the hole the same size. That may clean up the old threads so they hold. Don't over tighten, the threads may be a little thin. If you aren't sure of the thread size, take the bolt to the hardware and they will help you with the right size tap. 
 If that doesn't work you can drill and tap for the next size thread. I have seen individual taps packaged with the proper tap drill and that makes the job much easier.
 Don't forget to use plenty of oil. If you haven't used a tap, get it started and back it out 1/2 turn to clean out the shavings. Max one turn forward and back out 1/2 turn. Taps are brittle and a broken tap in a hole is not a pleasant experience. If you can, call a friend to help, he may have a tap and die set.
   Hope all goes well.
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Phil & Marsha Spicer-Dock at Sandusky Sailing Club-
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Jim Hardesty

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Re: Crossthreaded handrails
« Reply #2 on: April 07, 2021, 10:55:54 AM »

Quote
Well, it looks like one of the PO’s cross threaded one of the bolt holes on the port side stainless hand rail.

Not sure what you are describing.  Are you asking about the lifeline the fittings or the stanchion mounting bolts.  Turnbuckles and their mating fittings are one side right hand threads the other left hand threads. 
Jim
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girmann

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Re: Crossthreaded handrails
« Reply #3 on: April 07, 2021, 11:33:34 AM »

Quote
Well, it looks like one of the PO’s cross threaded one of the bolt holes on the port side stainless hand rail.

Not sure what you are describing.  Are you asking about the lifeline the fittings or the stanchion mounting bolts.  Turnbuckles and their mating fittings are one side right hand threads the other left hand threads. 
Jim

There are threads in the stainless steel handrail that’s mounted to the cabin top and these are what are cross threaded.
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girmann

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Re: Crossthreaded handrails
« Reply #4 on: April 07, 2021, 11:37:55 AM »

You could try to re tap the hole the same size. That may clean up the old threads so they hold. Don't over tighten, the threads may be a little thin. If you aren't sure of the thread size, take the bolt to the hardware and they will help you with the right size tap. 
 If that doesn't work you can drill and tap for the next size thread. I have seen individual taps packaged with the proper tap drill and that makes the job much easier.
 Don't forget to use plenty of oil. If you haven't used a tap, get it started and back it out 1/2 turn to clean out the shavings. Max one turn forward and back out 1/2 turn. Taps are brittle and a broken tap in a hole is not a pleasant experience. If you can, call a friend to help, he may have a tap and die set.
   Hope all goes well.

Phil,

Thanks for all the advice. I bit the bullet and bought a tap and die set. Spent the morning watching people do this on utube and then tried it myself. It seems to have worked!

For all those that run into this, I bought a tap and die set that covers lots of different sizes. If you just want to buy the one specifically for the handrails, they’re 5/16” 18tpi. It was a bit nerve wracking. I re-tapped the holes that were fine first, to get the feel of it. That worked out because there was still plenty of 4200 in the threads and re-tapping them got all of that out.

I’m going to re-bed the handrails with some Bed-it buytl tape so that it can be redone at some point in the future without too much need to clean up the threads.

Mark
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glennd3

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Re: Crossthreaded handrails
« Reply #5 on: April 07, 2021, 12:20:33 PM »

Mark you are a machinist now!
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Glenn Davis
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Phil Spicer

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Re: Crossthreaded handrails
« Reply #6 on: April 07, 2021, 01:34:36 PM »

  Mark, good to hear you got a tap and die set. You will find it to be like finally getting a dremel tool, " how did I get along without it." That set will last forever. Not something you use every week, but when you need it you have what you need right now. Tools are your friend, get good tools and they last. Your on your way to becoming "Tim the Tool Man."
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Phil & Marsha Spicer-Dock at Sandusky Sailing Club-
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KWKloeber

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Re: Crossthreaded handrails
« Reply #7 on: April 07, 2021, 02:04:26 PM »

When the Admiral says "We don't need a larger boat, buy more tools."
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girmann

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Re: Crossthreaded handrails
« Reply #8 on: April 08, 2021, 08:00:08 AM »

Okay, there's at least one coda to the whole story.

Remember how I said that I retapped all the holes to practice? Well, there was a bit of swarf that came from each of them and each one wasn't exactly perfect. Well, once I tried to put the machine screws back into the threads, none of them fit anymore. I know that I used the right tap because the set came with a measuring tool.

Here's what I think happened: As near as I can tell, each of the screws are slightly bent. So I'm guessing that each of the holes were also slightly bent, too? Re-tapping them might have straightened out the holes and not the bent screws don't go in. I can also tell that this had leaked before (corrosion and over-torqueing marks on the screwhead) and I'm wondering if one of the POs knew something was amiss and put it all back - rather than trying to fix it.

The other thing it could be is that my tap and die set from the orange store could be slightly off? I tried re-tapping (re-dying?) the screws and it was taking off a lot of material. I thought that maybe they were metric screws for a minute, but none of the metric sizes were even close to the 5/16" 18tpi. I don't know - maybe there's a metric size that wasn't in the kit that's close.

Anyway, I won't know any more until I get new screws tomorrow.

No matter how long I own a boat, I'm going to keep underestimating how long it takes to do something. Who would have thought I'd have 10 hours into rebedding ONE handrail?

Mark
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Noah

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Re: Crossthreaded handrails
« Reply #9 on: April 08, 2021, 08:06:35 AM »

Could it be a fine vs coarse thread issue?
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girmann

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Re: Crossthreaded handrails
« Reply #10 on: April 08, 2021, 08:24:55 AM »

Could it be a fine vs coarse thread issue?

The threads measured to 18tpi and the 18tpi measurement tool that came with the tap and die set fit into the threads exactly.
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Stu Jackson

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Re: Crossthreaded handrails
« Reply #11 on: April 08, 2021, 09:36:17 AM »

Whenever I redo something, I use new screws and bolts.  I keep the old ones and label where they came from.  I still have a ton of stanchion bolts.  :D

I'm still trying to figure out what "handrail" bolts you're dealing with as "...the port side stainless hand rail..."  If it's not the pushpit, what is the bolt being tapped into?  My handrails, the old wooden ones, have bolts, nuts and acorn nuts below.  I'm still trying to figure out what you're doing.  I'm rather dense.
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Noah

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Re: Crossthreaded handrails
« Reply #12 on: April 08, 2021, 10:06:58 AM »

I believe he has stainless steel grab rails on the outside coachroof which replaced the wooden ones that we have in our MKIs. If this is the case, I assume the rails are tapped to take a bolt up from below. I may be totally off base here. If my theory is true I would suggest retapping/chasing/clearing the threads in the base of the handrails, then use threaded rod into the handrails. Once the threaded (studs) are into the handrails—redrill new larger holes in the cabin top that line-up, then fill those with epoxy and redrill, then use butyl tape, nuts and cap-nuts below to secure. If I have your problem/goal all wrong, please disregard! :abd:
« Last Edit: April 08, 2021, 10:18:52 AM by Noah »
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girmann

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Re: Crossthreaded handrails
« Reply #13 on: April 08, 2021, 11:37:37 AM »

I believe he has stainless steel grab rails on the outside coachroof which replaced the wooden ones that we have in our MKIs. If this is the case, I assume the rails are tapped to take a bolt up from below. I may be totally off base here. If my theory is true I would suggest retapping/chasing/clearing the threads in the base of the handrails, then use threaded rod into the handrails. Once the threaded (studs) are into the handrails—redrill new larger holes in the cabin top that line-up, then fill those with epoxy and redrill, then use butyl tape, nuts and cap-nuts below to secure. If I have your problem/goal all wrong, please disregard! :abd:

DING DING! We have a winner!

I have a MkII, which doesn't have the wooden grab rails. Why use threaded rod when I could get another machine screw and not have to deal with nuts and cap nuts? The hole in the cabintop is already way oversize.
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girmann

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Re: Crossthreaded handrails
« Reply #14 on: April 08, 2021, 11:40:08 AM »

Whenever I redo something, I use new screws and bolts.  I keep the old ones and label where they came from.  I still have a ton of stanchion bolts.  :D

I'm still trying to figure out what "handrail" bolts you're dealing with as "...the port side stainless hand rail..."  If it's not the pushpit, what is the bolt being tapped into?  My handrails, the old wooden ones, have bolts, nuts and acorn nuts below.  I'm still trying to figure out what you're doing.  I'm rather dense.

Stu - that's for this - my next project is to pull all the stanchions and even after going through this I didn't think about ordering new. I guess I need to make the mistake twice before it sinks in. Since I only budgeted an hour for doing the grab rail (and 4 for the stanchions), if the same ratio holds then it should take a better part of a week to do the stanchions?

Mark
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