Bandsaw track adjustment screw stripped.

RobH

Rob
User
I bought a used laguna 14” 3000 bandsaw around 6 months ago. It’s been working well but the blade tracking screw for the upper wheel started slipping. I removed the screw and the threads are fully stripped, as is the screw hole on the bandsaw. The only remedy I can think of is to tap a larger hole in the same place and use a new bolt to make the adjustments. Anyone else have this problem or think of another solution?

I am guessing the previous owner was over torquing the screw with the nut up against the bandsaw rather than loosening the nut to make adjustments.
Old bolt looks to be 1/4 so I’ll likely tap 3/8-16

thanks for any input.
Rob
 

Phil S

Board of Directors, President
Phil Soper
Staff member
Corporate Member
How thick is the piece you are tapping? I am wondering if installing a helicoil might also be an option.
 

Oka

Oka
Corporate Member
I agree a Helicoil is the easiest option.

If you have a tig-welder You could fill it back with a Weldmold rod (maybe 954) check with a welding shop to get the correct compatibility rod for the steel. If I remember correctly, usually most power tools are some variation of L6 (iron alloyed with 0.65-.75% carbon, 0.6-1.21 chromium, 0.40% manganese, .05 molybdenum, 1.2- 2.0% nickel, and 0.03% each phosphorus and silicon), or 15n20 (iron alloyed with 0.88% carbon, 0.40% manganese, 2.0% nickel, and 0.10% phosphorus and silicon.

Either way once it is filled then you can re-drill and tap. The success to these kind of welds depend on getting a rod that is equal or just slightly harder or softer than the metal it is fusing to.
 

RobH

Rob
User
There is about 1/4 of sheet metal (two layers welded together) where the track adjustment bolt enters the frame behind the top wheel.
 

Mike Davis

Mike
Corporate Member
I would drill and tap with 5/16- 18 Drill size F or .2570 A 1/4 inch drill would work in mild steel if you are careful tapping so as not to break the tap.
For me that would be the quickest and safest way since I already have everything and know how to do it.
I have seen Helicoils fail several times.
 

Mike Davis

Mike
Corporate Member
If the force is up against the screw wouldn't it be stronger mounted inside the sheet metal?

Great idea by the way.
 

RobH

Rob
User
Thanks everyone. Great idea regarding adding the steel plate to the outside and using a bolt through that. I could use through bolts at the four corners and that way not worry about the plate pulling off.
I went ahead and tapped for a 3/8-16 bolt and it is working well. I figure if that strips then I will go with the steel plate idea. Adding a locking nut.
great community and great advice from everyone. Thanks a ton.
 

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junquecol

Bruce
User
Now that you have drilled and tapped hole, is there room enough on inside to "tack weld" a nut to strengthen your threads. For nut, bite the bullet and buy a grade 8, instead of the more common (grade 2-5) ones. Could be epoxied in place, as it's only supporting compression.
 

RobH

Rob
User
I’d have to take apart the whole wheel assembly to have room to add a bolt on the inside. Any strengthening of the threads would be best on the outside I think. Appreciate the advice on grade 8
 

tvrgeek

tvrgeek
User
A common miss-conception here. Probably not important for the band saw, but it scares me when this incorrect information is not corrected as it may lead to a place where it does matter.

Grade 8 bolds are weak steel that is HARDENED. Brittle. Do not confuse tinsel strength with strong. If you want a strong bolt, use a strong bolt. ( AN grade, ARP etc.) Go to someplace like Spruce Aircraft . Grade 8 may be used in non-critical tinsel only applications. Never in sheer. ( unless it is a stop bolt, a bolt and nut are never in compression. )
Grade 5 are not quite as brittle being a reasonable compromise between strength and brittleness
Grade 3 is a good bolt, if it was any good and sized correctly. I would not trust a big box store Chinese low bid bolt if my life depended on it. (Like in my car chassis) Never use a grade 8 in places like that. NEVER. Actually, I do not trust the steel in any hardware store bolt if strength is important.
An advantage of softer bolts is sometimes the bolt will strip before the tapped threads. Easy to replace a bolt, Harder to heilicoil a thread. In other applications, they wil yield (bend) rather than snap. Much nicer failure mode.

Basic engineering rule. If you need a stronger bolt, use a bigger bolt.
 

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