Helicoil and blade raising thread

[woodturner]

Just picked up another BT3000 off Craigs list, but it has a stripped blade raising thread so I need to install a helicoil.

Found the article in the list, and it appears that 9/16-12 is the thread size. Anyone know if that is universal for all BT3000s?

Looks like the Helicoil kits are up to $30 or so now, though the inserts are still inexpensive. Is the tap for a Helicoil different from a normal tap, or will a tap the next size up work fine? I'm trying to avoid buying more tools I'll use only once

Maybe we could start a tool lending library for commonly needed BT3X repair tools

[Tom Slick]

Helicoil taps are specific to helicoil; You'll need a tap and install tool.

[drillman88]

If you have a set of large taps and there is enough meat around the hole, you can drill and tap it to 5/8. Then put a piece of all thread in using red loctite and drill and tap this out to 9/16 after the loctite sets. You are basically plugging the hole and redrilling it.
We do this type of repair at work quite a bit and it works well.

I am not sure if it is possible but i was throwing the idea out there.

[woodturner]

If you have a set of large taps and there is enough meat around the hole, you can drill and tap it to 5/8. Then put a piece of all thread in using red loctite then drill and tap this out to 9/16 after the loctite sets. You are basically plugging the hole and redrilling it.
We do this type of repair at work quite a bit and it works well.

I am not sure if it is possible but i was throwing the idea out there.

I appreciate the suggestion, interesting idea. In this case, though, the aluminum casting has a "sleeve" that extends out from the base, and this sleeve is tapped. There is maybe 1/8" of material surrounding the hole, so there is not a lot of extra material. Do you think this would still work, or is that too little material?

[drillman88]

From your description I wouldnt think so. The helicoil would probably be best. You may be able to tap the hole to 5/8 and change the bolt or threaded rod on the machanism to 5/8.
After thinking about it a 5/8 plug wouldn't leave enough strength to drill and tap a 9/16 hole. 3/4 would be the best for this applicaion. If you went to 3/4 to plug the hole you would be really close to or would take out the sleave.

[LCHIEN]

...Found the article in the list, and it appears that 9/16-12 is the thread size. Anyone know if that is universal for all BT3000s?

...Maybe we could start a tool lending library for commonly needed BT3X repair tools

as far as I know, the 9/16-12 is common to all BT3 variants.

We did have a floating kit but it was lost when someone broke the chain.

[woodturner]

as far as I know, the 9/16-12 is common to all BT3 variants.

OK, thanks. The guy I bought the saw from turned out to be the owner of a local sharpening and machinery sales and repair dealer. He had taken it in trade, ordered a replacement part from Ryobi, with the right part number, but the one they sent him was not the right part. IIRC, the one they sent had square corners on the casting, while the one on the saw has rounded corners. He said it was close but didn't quite fit.

I'll check the threaded rod before starting the repair, just to make certain.

We did have a floating kit but it was lost when someone broke the chain.

I'm going to check with the ME department to see if they might have a set. If not, I guess I will have to buy one. In that event, maybe we can try the floating kit idea another try.

Thanks.

[Stytooner]

Before buying, you might check with an auto parts store. Our Advance Auto will rent odd tools out cheaply.

[jeepman71]

Possibly a threadsert would work. I believe they use two sizes up as far a tap sizes. Been too long since I have used these. Here is some information.

http://www.timesert.com/

Jeepman71

[woodturner]

Possibly a threadsert would work. I believe they use two sizes up as far a tap sizes. Been too long since I have used these. Here is some information.

http://www.timesert.com/

That does look like a better solution, but the kits are rather expensive (~$120).

I'll ask around and check to see if they are available as loaner tools anywhere.

[Black wallnut]

I would steer away from the linked threadsert as it appears from the product description that it has locking threads. It also does not say what material it is made from. Heli-coil is stainless and is a proven solution to this problem. The only hard part is making sure that you drill straight, and then making sure your tap follows straight. Once you do this apply a bit of locTite to the threads (external) when you install the insert.

[JimD]

I thought I needed a helicoil once but it was just that the height mechanism needed lubricated and the plastic handle was turning on the steel shaft. Probably that isn't your problem but I thought I would mention it. Mine is a BT3100 and I think it would be pretty hard to strip the threads using the plastic handle.

Jim

[jeepman71]

http://www.ezlok.com/InsertsMetal/installation.html

This is a product that we used at Ford motor rebuilders in the 80s. I believe if memory serves that the tap size is a normal size.

Jeepman71

[jdon]

The e-z lok looks like an interesting alternative to Heli-coil - cheaper (quick web check:~$10 for 5). Only potential drawbacks I see are:

1) fewer threads (shorter insert: .656 vs .844 in. for H-C)

2) slightly larger drill out (21/32 vs. 19/32).

Anyone have any experience with E-z lok with BT3k? BTW, unless I'm missing something, a Heli-coil kit isn't outrageously more expensive: toolsource.com has a kit for 39.70.

I'm trying to avoid needing such a repair, but always good to have the knowledge available.

[mnmphd]

When this happened to my bt3100, the easier and cheaper solution was to replace the part. I am pretty sure it was less $30. I had to swap the bearing/pully assembly but I figured that was less prone to error than
boring/tapping/inserting the helicoil. That said, I kept the older motor bracket
in case I ever got easy access to a helicoil kit.