A discovery: Inserting Threaded Inserts

I made a new (router) dado jig this morning. My old one was made in haste for a bookcase project. It worked fine, especially once I made it (more easily) adjustable, but it's not long enough for a project I have in mind.

To adjust the dado width, I used threaded (female) inserts and star knobs. The last time I used those inserts I had a devil of a time getting them into the wood. Some people here suggested cutting the head off a 1/4-20 bolt, chucking it into a drill, and threading a pair of nuts onto it as a back stop.

That sounded like a good idea, and I was just about to cut the head off a bolt when another idea struck me. I threaded the insert onto the knob itself, all the way to the body of the knob. Then I turned the insert into the wood by hand with the knob. When the knob touched the wood, I backed the knob out of the insert.

To my surprise, it really was flush with the wood, but I turned it in another half-turn with a screwdriver anyway. In retrospect, I could have eliminated that step by putting a washer (one whose outer diameter was smaller than the insert) onto the knob threads before putting on the insert.

It's probably not a better method than the one suggested here if you're doing a lot of them, but it worked fine.

Reply to
Greg Guarino
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Most of those knobs will crack under extreme pressure. So you are lucky. I have had too many crack without that pressure.

Reply to
woodchucker

Taking those two statements together makes me wonder if you're installing them upside down?

Most likely not, but you never know ... so don't take offense.

Reply to
Swingman

... hope I didn't read your post wrong ?

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.. is this what you need ?

John T.

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Reply to
hubops

The most important component of what I needed was that it be here

*today*. But yes, those would have worked also.
Reply to
Greg Guarino

I've never been clear on which end was up. But yes, I had the "notches" facing up. I suppose if esthetics was a concern, the other way might be preferable, but this seems to work fine.

Reply to
Greg Guarino

Perhaps you are just too damn strong? :)

I don't think I would describe the force I used as "extreme". But I see your point.

Reply to
Greg Guarino

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Reply to
Greg Guarino

Notch up, there is even a drill insertion bit that engages those slots.

Reply to
Leon

Actually, the notches are designed to facilitate the cutting of the threads and should go down in hardwoods.

Do it that way in hardwoods and you'll never go back.

From a catalog for threaded inserts designed for use in wood:

"For most wood applications including medium-hard and hardwood, the threaded insert should be installed slot down. The cutting action at the slotted section allows easier installation and avoids radial stresses which may otherwise tend to split the wood."

"In soft wood, the threaded insert should be installed slot up. The threaded insert is then thread forming, similar to a wood screw. The absence of cutting provides a firm anchor in the relatively soft wood."

Reply to
Swingman

Hummmmmmmmmmmm OMG

Do you have a picture of the insert in question? I have some old brass inserts with the slots. Anyway there are apparently numerous styles of threaded inserts. I pretty much get the zinc style these days with a flared top.

Here are my insertion instructions for my brass slotted inserts. Specifically they want the slots up so that the special threads hold better.

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Reply to
Leon

Since it was ply, likely birch (it was scrap), maybe I got it right. But thanks for the tip.

Reply to
Greg Guarino

Well for one it shows the slot up as I think it should be, at least with this particular insert. Some indicate that their instructions indicate the slot can be down to help cut into the wood. BUT looking at these inserts the slots are not near or touching the wood. So apparently there are some inserts where the slot is at the outer edge of the insert too.

Reply to
Leon

Oh, and the "devil of a time" comment was mostly due to trying to put the insert in with a slot screwdriver. It was the widest one I had, but still a tad narrower than it needed to be. It was just wide enough to grab both slots - a little - but slipped out often. It's also difficult to get it started plumb that way. My "new method" was much better.

Reply to
Greg Guarino

As he and I both have pointed out, there are several types of inserts with the slot. Mine are specifically to be used with the slot up, some can be used wither way. If yours are intended to to be used either way using a screw driver might be more problematic. OR you need to get a decent set of screw drivers. :~)

Reply to
Leon

I hadn't come across the type that flips over .. The other most common type - use a hex driver -

- and slightly different size pilot hole for different woods. John T.

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Reply to
hubops

Leon wrote in news:8bCdnb9DR snipped-for-privacy@giganews.com:

The only inserts I've ever seen that go in slot-down are the press-in style you find in cheap furniture (and in those the slot is intended to allow the insert body to flex, it's not for driving).

Like Greg, I found the Hillman brand inserts (the ones stocked by Home Depot and Lowes) to be undrivable with a screwdriver, despite that evidently being the manufacturers intention, due to the slot not being well formed - a screwdriver with a tip thick enough to fit the slot well is wider than the insert (also, the metal is weak, due to the slot being so wide, and likely to break if you exert any force on the slot).

If you can find them, the style with a hex recess are far and away the best inserts (and, obviously, go in hex-upwards).

John

Reply to
John McCoy

A drill is about the only way I can get them in straight. No matter what technique I try to use, when I do it by hand there is inevitably some angle to them when I'm finished because of having to stop turning while pushing to reposition the hand. Those suckers reeeeally want to go in crooked. A drill is the only way I seem to be able to hold them perfect;y straight while driving them in.

Reply to
-MIKE-

The answer is in the picture. Yours doesn't have the threads coming up all the way to the top-- it is rounded and smooth all the way around. If you look at the one diagrammed in those instructions, you will see the the threads come all the way to the top, with the slot dissecting the threads. That insert style would definitely cut hardwood when being driven slot-side down. They are also the ones I always break bits off of at that particular section when trying to drive them with a flat-head! :-D

Reply to
-MIKE-

Not to mention I would rather let the drill do the work. ;~)

Reply to
Leon

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