Stripped Throat Plate Screw Holes - BT3000

[nickg]

Anyone else ever have a problem with the throat plate screw holes stripping out? How did you fix it? I was thinking of using HeliCoils and the same size screws, or re-tapping for a slightly larger screw. I'm guessing this is a fairly common problem with an aluminum platform, and regularly removed screws (blade changes).

BTW, because I had to use the saw, I temporarily used some 'Blue' Loctite to hold the screw down (it worked!)

[eezlock]

stripped throat plate screw holes

I haven't had those screw holes to strip out, but I think the best solution is to buy some new screws that will sit flush with the throat plate and re-tap the threads with the proper tap....it is really easy to do in aluminum anyway.

[LCHIEN]

I haven't had those screw holes to strip out, but I think the best solution is to buy some new screws that will sit flush with the throat plate and re-tap the threads with the proper tap....it is really easy to do in aluminum anyway.

I'm with EZLock on this. There's never a real reason to tighten the throat plate screws very hard - you should be aware that the threads are in aluminum.

I believe the screws are a commonly available thread, #10-24, according to my FAQ. Actually there are two sets of holes, three for the factory metal plates and four for the plastic cut-it-yourself plates. If you've never used the pastic cut-it-yourself plates, you have to use a self tapping screw to start the holes as they don't come tapped from the factory.
The next imperial size after #10-24 is going to be 1/4"-20 or 1/4"-28. Since its relatively thin you might want to use the 1/4-28 threads per inch to get more hold in the table. Both should be available in a flat head at your local hardware store. Before you cut You'll want to check the head thickness and make sure it can go in the throat plate and not stick up. I've not actually had anyone report doing this.

Do a forum search here for stripped throat plate screw for related information, but, as I said, I had not found anyone having done this before,

Good luck.

[cabinetman]

1/4-20 sounds pretty big for that application.

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[capncarl]

I've used threaded inserts (Pop nut, Nut sert) for sheet metal applications like this where limited threads are available. They work great on removable panels. In this case have you tried a sheet metal screw in the countersunk hole? The threads are already gone so you are not messing up anything so this may buy you some time until a suitable repair is possible.
capncarl

[Stytooner]

Well, there are also number 12's between 10's and 1/4". The biggest issue with going to a larger thread is that is also a larger head size. You would need a really nice countersink tool to get it as precise as it needs to be.
When it is this small though, a threaded insert might be the best choice so that you can keep the 10-24 thread size. Something that may even be cheaper and easier is just filling the holes completely with JB Weld. Then drilling and retapping for 10-24. That is what I would do in this case. The threads do not need to retain much meaning very little torque needed.

Sometimes things like this can be done with the next size metric tap easier. The main issue with that is metric fasteners usually have a larger head than similar SAE sizes. Not always, but often enough to consider that.

[capncarl]

Another problem caused by changing sizes is getting the screws mixed up when changing parts. If/when mine strips out I'll look at fabricating a back up plate that adds depth to all of the threaded holes, and use 2 of the existing unused holes to pull up the back up plate.
capncarl

[nickg]

As a follow-up, I repaired the stripped out throat plate threads on the BT3000 today. I decided to go the Heli-Coil (actually 'Perma-Coil') route. Only one of the three screw holes was stripped, but I went ahead and did all three while I was at it. Repair was quicker than I thought it would be - easy to cut new threads in aluminum.

Thanks for your advice and suggestions!

[woodturner]

Something that may even be cheaper and easier is just filling the holes completely with JB Weld. Then drilling and retapping for 10-24. That is what I would do in this case. The threads do not need to retain much meaning very little torque needed.

I realize the OP has already solved his issue, but just wanted to add a +1 for JB Weld. "Discovered" JB Weld a few years ago and am surprised at how well it works. I've used it several times for repairs on our '98 Chrysler - to fill and "re-tap" the transmission dipstick tube bolt, overflow tank hold down, etc. It's great for fasteners in tight quarters.

What I do it coat the fastener threads and the hole with JB Weld, assemble and clamp, then wipe off the excess and let cure. When cured (I wait at least overnight), the fastener can be removed, leaving perfect threads behind, with no tapping required.

Now you have me thinking - I wonder if it would work to repair the stripped blade raising threads on the BT3X. Might have to try that before resorting to the overdrill, rethread, and install insert route.

[Stytooner]

In my experience with JB Weld, it is really intended to be used fairly thin. Meaning not really structural. If an acme thread is stripped out, I think that would mean a structural replacement would be needed.
Now it may very well work. JB Weld was formulated originally to repair scored, scratched and pitted cylinder walls. I have held my usuage to pretty thin applications. I have heard of others using it structurally, but not sure how strong that would actually be.
I do know that because the thing stripped out to start with, there are abnormal forces working on that part already. Not sure JB Weld would be up to the task.

BTW, I have used it similar to what you mention. I made sure the bolt has a light film coating though, like petroleum jelly or even 3 in 1 oil. Then nothing is disturbed when unscrewed. It helps to have a good quality screw or bolt too with good thread tolerances.


PS: I edited this because I had written god quality screws with goo threads. That high of quality screw will certainly not have goo threads.

[jdon]

Before this thread dissolves, does anyone have advice re: leveling screws that turn too easily- not stripped, but seem to lower on their own over time with pressure on the plate, vibrations, whatever.

I don't want something like Loctite to freeze the position- something to give just a bit more friction on the threads. Any ideas?

[Stytooner]

Actually there are many different grades of Loctite and thread lockers in general.
Since this isn't adjusted very often, I would think a mild green penetrating thread locker would suit. You would be able to adjust later, but it would hold in place for now. Then just reapply.

[nickg]

The JB Weld method would be worth trying. The drawback with the threaded inserts (Heli-Coil or Perma-Coil) like I did, is the cost . They do a neat job alright, but those little guys are expensive!! I shopped around by phone, and the local auto auto parts stores either didn't have the right size or didn't know what thread inserts were, one place would special order it though. Anyway, I ordered from Amazon for $24 including freight (not a 'Prime' item). Guess the thread repairs kits are expensive because you get a correctly sized tap, an inserting tool, plus a dozen inserts - you supply the correct size drill.

[RAV2]

Before this thread dissolves, does anyone have advice re: leveling screws that turn too easily- not stripped, but seem to lower on their own over time with pressure on the plate, vibrations, whatever.

I don't want something like Loctite to freeze the position- something to give just a bit more friction on the threads. Any ideas?

Teflon tape on the threads before inserting....

[cabinetman]

Teflon tape on the threads before inserting....

That would work.

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