Metal threaded inserts for wood allow you to assemble components to each other such as wood to wood and metal. But all inserts are not created equal. Have we found the best inserts yet? We think so, but you be the judge!
Threaded inserts for wood have grown in popularity over recent years. Like many things that were once reserved for professional use, threaded inserts are now being used in the maker shop and by homeowners to make RTA (ready-to-assemble) or KD (knock-down) furniture, as well as adjustable jigs and fixtures.
These inserts have also become really popular for use with “live edge” slab furniture, where a finished thick slab of natural edge wood is attached to metal legs or supports, or even other wood components.
The inserts are a simple and brilliant invention. They are barrel-shaped, with cutting threads on the outside, and machine screw threading on the inside.
Depending on the size of the insert you are using, a specific diameter drill bit is used to drill a hole. Then the insert is screwed into the hole, and the driver device is extracted, leaving the insert in the wood. Then, a matching machine screw can be screwed into the insert, as the screw is passed through whatever is being affixed together.
While this is a general description of how these devices work, we think that one company (Rampa-Tec) offers a superior insert.
We’ve used and reviewed these types of inserts before - namely the E-Z Lok® brass product. You can see our review and installation guide here:
Since that review, we’ve encountered inserts and machine bolt sets from Rampa Tec®. The product is German-engineered & manufactured, stocked & shipped across North America from a Toronto area warehouse.
The company has been around for a LONG time - it was founded in 1907, and is very well known in Europe for its quality inserts used both in wood and metal products manufacturing.
While Rampa Tec makes a wide variety of products, in this episode we are taking a look at the patented SKD330 style. This particular line has become very popular with companies and individuals making live-edge furniture. It’s a zinc-plated steel insert, available in both metric and imperial sizes.
So, what makes the SKD330 superior to other inserts?
For starters, it has 3 external threads (instead of the usual 1) that eliminate troublesome installation tilting & twisting. This means the inserts are perfectly straight every time.
Next, there is an internal hex shoulder to drive the insert using standard hex drives - either by hand or chucked in a cordless drill. Driving in the insert is sure with no slippage or damage.
Because there are three external threads all working together, the insert works exceptionally well in a variety of wood-based materials - softwood, hardwood, particle board, plywood, or MDF. With this superior holding power, no adhesive is needed to keep the insert in place. However, should the need arise, the insert can be removed readily using the correct hex driver.
Lastly, these inserts have a sealing collar that not only provides a clean stopping point, but the insert will countersink itself beautifully!
For M6 inserts, pre-drill with a 10-10.5 mm or closest imperial (13/32”) drill bit. For M8 inserts- pre-drill with a 12-12.5mm or closest imperial (1/2”). Make the depth of the hole about 2 mm or 3/32” deeper than the length of the insert. Always do a test in the same material to assure that the density of that material doesn’t affect installation.
Rampa Tec® offers pan, mushroom, and flathead bolts in a variety of finishes as well. If you are using imperial sizes, they offer only ¼-20 bolts at this time.
To get more information on where to buy Rampa's SKD330 fastener, visit:
While these inserts are only available in bulk sizes, they are worth having a supply in the shop. While more expensive than single-thread brass inserts, they are superior and a very good value.
For 60 days after the premiere of this episode, Rampa will provide you with a 7% discount when you use the coupon code dirtfarmerjay23! The offer expires on March 7th, 2023.
Let us know what you think!
JUST DO IT YOURSELF!
Hey, Dirt Farmer Jay here from DirtFarmerJay.com.
Metal inserts for wood allow you to join
two components together,
whether they're wood to wood or wood to metal,
but all inserts are not created equal.
Have we found the best inserts yet?
Well, we think so, but you be the judge.
Hey, Dirt Farmer Jay here from DirtFarmerJay.com.
We have come to depend on these types of devices
pretty heavily in the maker shop here.
These are threaded inserts that allow you
to drill a hole in wood, drive the insert into the wood,
and then the inside of the insert has threading
that allows you to put a bolt in it.
So these have become quite handy,
especially those people that are making
live edge slab furniture,
where you're taking a really thick piece of wood
and then affixing other legs to it
that may be metal or other wood legs,
but you need bolt connection.
Something that's very secure with great pull-out resistance.
Now, what has been most commonly known for a long time
are the threadlock type of fasteners.
These are typically brass.
They have a slot on one end that use a specialized driver
or a wide blade to drive them in.
And these have been around for quite a while.
And the company that makes these
actually makes that kind of fastener as well.
If you're interested in seeing these installed
in an installation tool or methods of installing them,
you can check out the link at the top
or in the description below,
where we'll show you how to walk through that.
However, these are not the focus
of what we're gonna do today.
And the reason for that,
we think we have found a superior fastener through Rampa.
Rampa Tech, who is a German company
that now has broad distribution in North America
through Canada and the United States,
has these fasteners that are really well-engineered.
Now, what's the big difference
between one of these and one of these?
Well, if you look close right off,
you can see that the thread spacing's different.
You essentially have a barrel-shaped device,
some way to drive it into the wood
after you've drilled out the right specified hole size.
And then afterwards,
you're able to thread into the top of it.
Well, look at the difference here, though.
On this one, you have a single thread
that starts right here
and then just winds itself around the barrel.
It's very sharp, very efficient in cutting.
However, because there's only one thread
with one starting point,
the biggest problem with these
and why you have to use specialized installation tools
is that you start it,
it wants to turn sideways in the hole
instead of going in straight.
So what has Rampa Tech done?
Well, they went to their engineers and said,
this is the big fallback or big failure of these inserts,
of trying to get them to go in straight
and to be perpendicular to the surface
of where you're inserting them.
So what the engineers did
is they took threads,
three different threads that emanate
at three points around this,
so 120 degrees apart from each other,
and they end up at the end of the barrel at 120 degrees.
So there are three different thread starts.
So when you put this in a hole,
use a driver to start to drive it,
it isn't gonna go sideways.
It's gonna settle in
because it's like a three-legged stool.
And now you can drive them in using a standard driver
or one that you can get from Rampa Tech.
These are those standard quarter inch impact drivers.
They also have them for metric type of sizes.
So you just simply put this in,
let the chuck go,
and now that is trapped in there
and now it can be used to drive inserts.
There's another compelling difference
between this type of device and this one.
This one has a countersink shoulder on it.
So you'll see this ring around the top.
So when you drive it,
it actually countersinks itself just below the surface.
And this can now be removed again using that hex driver.
So these are very sturdy, very heavy duty, zinc plated,
and they are self depth setting.
As long as you've drilled it
where there's approximately two millimeters of space
under the barrel to allow it to sink in correctly,
then you're gonna end up with a good installation.
If you go and visit Rampa Tech
and you'll see the website address
in the description below,
you're gonna be looking for the SKD 330 type.
These have these great threads
that not only allow it to be inserted
in the hole straight without tilting over,
but these have superior holding power
for all wood related products such as hardwood,
softwood, plywood, particle board, and MDF.
You'll be really pleased with the fact
that these don't back out either
when you're taking the tool out
and no adhesive is required to get them to stay in place
and to do their job.
In addition to offering these great inserts,
they also offer a matching set of fasteners
that are in various finishes.
As you can see here, zinc or the bronze or black.
They're just really nice.
And they come in three different styles.
I only have two of them here,
but flathead with the hex driver in it.
These are all flathead.
And then here is a mushroom one that has a nice finish.
And they also carry a pan head, all using hex drivers.
You should be aware that Rampatek offers a full range
of these type of fasteners for their metric line.
However, if you're working in Imperial
and using their Imperial line,
they only offer it for quarter 20 threads,
which that's quarter 20 thread.
And that's a pretty standard here in the United States.
But be aware, you can't get really large ones
or small ones if you're doing Imperial sizes.
All right, let's go ahead and install some of these.
I have a piece of walnut here
that will show you how well these go into hardwood.
So you can kind of get an idea here.
Now, the first thing we need to do
is we need to set a depth gauge.
I'm using a half inch bit.
Yes, that's an Imperial size,
but that's one of the specified sizes
for using their M8 driver.
So we can drive a half inch hole,
and then this bit, or excuse me,
these threads will grip just perfectly.
However, the hole needs to be a little bit deeper.
So what I'm going to do is put that there
and then put a piece of tape as a flag for a depth gauge.
Here we go.
All right, let's put that there.
Let that hang over just a bit.
Let's go ahead and put that tape on.
There we go.
And now I can come right down to that flag
and we're going to be fine.
Now, let's suppose that I had precisely marked
where I needed these holes,
and it was right there and one over here.
So let's just go ahead and drill those two,
and then we'll insert these and see how it goes.
So we want to go ahead and put the Brad point
right in the center of the hole,
put this up as perpendicular as possible,
and then go ahead and drill.
And we really love these Brad point bits.
As soon as it gets down here and starts sweeping away,
you know that you've hit the flag.
So there you go.
So now we'll move over here.
Let's do the same thing here.
Perpendicular, right there.
There we go.
All right, we'll go ahead and get this out of here.
Now we're going to go ahead
and put one of the inserts right there.
We'll just kind of start it.
I've just kind of very lightly put it in place.
We'll go ahead and take one of the drivers
that's made for this.
You can use the L-shaped one if you like,
or something like a T-driver out of your supply.
But I'm just going to put this forward
and just let it rotate it in.
And notice that it's seated right below the surface there.
Really clean.
Very nice.
Let's do that again.
And again, you don't try to do this real quick,
but notice how quickly the driver does insert
this device into the wood.
Here we go.
Bam.
We now have threads in the wood
that is clean, beautiful, accurate,
and you saw no tendency for those inserts to tilt
when we were driving them.
So now we go ahead and say,
let's suppose we're going to fix something else to it.
Look at there.
It's as beautiful as can be.
Goes on quickly.
It's just really nice.
All right, let me show you another great feature here.
And that is, if you need to take these out,
you made a mistake,
or you wanted, you know,
you're dismantling something, not going to use it,
just reverse them out.
Look at this.
Because this is an industrial product,
it's going to be more expensive
than the consumer or retail type of products
that you've seen.
However, we really think it's worth it.
And you can go directly under their website,
which we'll show below,
and you can order.
And until March 7th, 2023,
you can get a 7% discount off of their bulk packs
when you use the coupon code DIRTFARMERJ23.
That's DIRTFARMERJ, all one word, J-A-Y 23,
the number 23,
and enjoy that 7% discount.
You can also check out the link below
where there's an animation
showing the installation of these type of inserts,
comparing them against other materials,
and that sort of thing you might find to be enjoyable
and informative as well.
Like you, we really appreciate great tools,
and we really like these Brad Point drill bits
from Montana Brand Tools.
We did a review on them.
We've been very pleased.
They're made in the United States,
and boy, are they strong performers.
Check out this video over here
where we did a full review on them,
and you can go there and use a coupon code also
to buy these at a discount.
And then while you're at it,
check out this other video that we made just for you
that we know you'll like.
Until the next time,
this is DIRTFARMERJ from DIRTFARMERJ.com.
