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Forum topic by swarfrat posted 06-25-2014 10:18 AM 1631 views 0 times favorited 12 replies Add to Favorites Watch
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39 posts in 1632 days

06-25-2014 10:18 AM

I’m putting threaded inserts into wenge. It’s super hard and splinter prone, and the insert started pulling up chips, so I’m tapping first. EZ Lok 300-008 external threads are 5/16-16. I did the math and a test in oak, and a common 3/8-16 tap has about 50% thread engagement and fits snug in the hole.

Is it ok, or perhaps even a good idea to tap 3/8-16 and epoxy the insert in place rather than trying to tap it 5/16-16? It’s going in a guitar neck, 8-32 machine screws and typically installed “snugly”.

12 replies so far

View Redoak49's profile


3606 posts in 2166 days

#1 posted 06-25-2014 11:35 AM

Wenge is a difficult wood to work with. I think your idea is good but would test it in a scrap and make certain the epoxy will hold in the Wenge.

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39 posts in 1632 days

#2 posted 06-25-2014 12:56 PM

I don’t have any scrap wenge. There is a supplier a few towns over but buying 1 bf for 16.75 to drill practice holes is hard to stomach. Not as hard as screwing up a $300 neck thouh, so I’ll probably do it anyway after testing in oak. It just pains me to buy scrap wood.

View MrRon's profile


5150 posts in 3420 days

#3 posted 06-25-2014 04:38 PM

A 3/8-16 tap takes a 5/16” drill. Try a drill one size smaller (19/64”). This should give you a tighter fit.

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39 posts in 1632 days

#4 posted 06-26-2014 01:06 AM

I found an old thread here supporting the idea of tapping a hair oversize and using glue. Wenge is dense but not super oily. Saw several mentions of titebond ii. But what about letting thin CA fill the thread gap? Its not a traditional glue joint It’s basically a rigid equivalent to Teflon tape. It does need to get a grip on the brass too, nut that can be purely mechanical. They even provide a handy anti rotation slot in the bottom cleverly disguised to look like a screwdriver slot in the top

View shampeon's profile


1860 posts in 2360 days

#5 posted 06-26-2014 01:46 AM

I just tapped the wood on this wenge marking gauge, then squirted in thin CA for extra strength.
Click for details

-- ian | "You can't stop what's coming. It ain't all waiting on you. That's vanity."

View hairy's profile


2780 posts in 3709 days

#6 posted 06-26-2014 12:27 PM

When I tap wood, I use a slightly smaller bit than would be called for in metal to drill and tap the same hole. I have not had good luck tapping end grain. It drills and taps easy enough, it just won’t hold for long. Drill, then tap, then flood with thin CA glue. Wait until the glue is definitely dry, then re – tap.

Have you seen this?

-- My reality check bounced...

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39 posts in 1632 days

#7 posted 06-26-2014 02:04 PM

Yes. I’m using ez lok 400-008. They don’t publish the external thread specs but it’s. 5/16-16. Something I just thought of since I do have a lathe is just drilling and tapping a 3/8-16 bolt and calling it a day. I don’t know why it never occurred to me.

View longgone's profile


5688 posts in 3486 days

#8 posted 06-26-2014 03:01 PM

Many wood such as oak are easier to tap than Wenge. Another solution would be to drill a 1/2” hole in the Wenge and insert a dowel that can be tapped more successfully.. I’ve done this in softer woods to strengthen them for inserting pin hinges.

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39 posts in 1632 days

#9 posted 06-26-2014 06:06 PM

An oak insert to hold the brass insert to hold the machine screw?

View ADHDan's profile


800 posts in 2286 days

#10 posted 06-26-2014 06:19 PM

Despite the “Ms. O’Leary’s Cow” aspect of Greg’s solution, that’s what I’ve done to install threaded inserts in materials that tend to strip out, such as softer woods and particleboard.

-- Dan in Minneapolis, woodworking since 11/11.

View MrRon's profile


5150 posts in 3420 days

#11 posted 06-26-2014 08:43 PM

You could use a helicoil insert.

View Brett's profile


49 posts in 1506 days

#12 posted 10-30-2014 01:38 PM

You could use a helicoil insert.

- MrRon

It is difficult to work with but I agree with Ron, helicoil insert would be the best approach.

-- Brett, United Kingdom,

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