I recently purchased 12 brands of parallel clamps with the intention
of doing a very thorough review. But then I hit a wall.
So once I had all these clamps in the shop,
I sat down to think about how we would test them.
You know, how could we be fair? It's 12 different brands.
What kind of tests can we possibly run with one sample from each
brand and consider it good information that's actionable?
That's a really hard thing to do. So I needed a little inspiration.
I looked at some of the other reviews that are out there,
even an old magazine review that you know,
should be very reputable. And I looked at the testing parameters
and I left scratching my head on some of these. In some cases
I don't think people totally understand why these clamps are built
the way that they are and what they're supposed to do.
So, while I think I failed in my mission of coming up with a good
way to test all of these clamps. I did wind up walking away with
some additional insights. I learned some things as I was looking
at these that I think you guys might want to know about
that will help you understand what these clamps do
and how we're supposed to use them. And then at the very least,
maybe you'll be able to look at some of these other reviews out
there and look at their testing parameters
and be able to make a decision as to whether their verdict at
the end actually means anything because it might not.
But I want you guys to be informed on all this stuff.
So here we go. The head on a parallel clamp should not be square
out of all 12 of these brands. I think 11 out of the 12 had toed
in heads. That's by design. And the reason is
because when you put this clamp under pressure,
that's when the heads become parallel, not in its resting state.
So if you see someone testing clamps and they consider it a fault
when they put a square on here and this head isn't square to
the bar, they might not know what they're talking about.
Let's go to the whiteboard. Right. So here's a precisely drawn
parallel clamp and you can see I have an exaggerated toe in just
for effect here. So we can understand also understand
that the movable head sometimes does not sit uh toed in just
because it, it's got, you know, some wiggle room there.
But ultimately, the goal is for these to be toed in.
So let's assume we're clamping a nice big work piece like this.
And we're making use of the entire head on the clamp as we tighten
this down. Here's what's going to happen. These clamp heads are
actually going to go vertical. They're going to conform to the
shape of the work piece. And the way they do this is not by the
head kind of flexing in its position, it's by the bar at the bottom
deflecting. So as that bar changes like this again,
exaggerated the angle effectively has become parallel clamping
nice and even along this entire edge, but the bar bending is the
mode of action that allows that to occur. Now,
once again, we're going to exaggerate here.
But let's look at what might happen if the heads start square
to the bar, right. So with no pressure, here's our clamp head
nice and square, nice and square. Now, once we start to apply
that pressure, this bar is going to flex no matter what the heads
are doing, that bar will flex. So what was square will now go
out the other way as that pressure is applied,
potentially resulting in a gap and a lack of contact at the top
of the head. This is why toeing in is by design.
And let's look at this on actual work pieces,
you can see when regular pressure is applied
and the entire clamp head is being used, the good clamps will
seat cleanly on the work, they'll square up
and they'll have minimal gaps, bringing the fixed head
and the movable head into a parallel state.
But if the clamp starts square and you apply pressure across the
entire head, there's a good chance that the head will actually
open up at the top, which means that pressure is no longer balanced
and it's inconsistent. Now, I wouldn't say
that it's totally worthless to put a square onto a clamp,
but do it so that you can confirm that there's some toe in.
It's going to vary from clamp to clamp and some of them might
be square. So grab the ones that at least have a little bit of
toe in and maybe even avoid the ones that have too much toe in.
Find that middle road. But outside of that,
there's really not a whole lot of reason to put a square on a
parallel clamp. Number two, deflection happens,
bar deflection is going to happen to every parallel clamp.
With no exceptions, the bars that they use for parallel clamps
just aren't thick enough or wide enough to withstand all of
that force without deflecting. So it doesn't actually do us any
good to measure deflection and use it as sort of a pass fail metric.
Well, maybe, but only if we can make the force we're applying
consistent. Let's take, for example, Bessey versus Jet.
Bessey is rated at 1,700 lbs of force and Jet is rated at only 1,000 lbs.
Now, if I'm testing deflection by cranking down as hard as I can.
And for the sake of argument, let's assume
that I'm able to get somewhere near that maximum force.
That means that the Bessey in that same test would be applying
700 lbs more force than the Jet. And as a result,
it's going to have a lot more deflection. And let's say we test
it a little bit differently. What if we just apply the amount
of force that feels right, kind of the amount of force we might
apply when making panels in our shop, for instance.
Well, that just comes down to feel and a lot of guesswork
because a lot of what we feel with the comfort of twisting,
this handle comes down to the handle itself,
it comes down to the screw, the pitch of the threads if there's
any lubrication on that screw. And then ultimately,
what the clamp is capable of. So it's really hard just to go by
feel and say, yeah, the clamping force is consistent across all
of these test subjects. Now, on the other hand,
if we did have a way to equalize that force across each of the
clamps, so you have 12 clamps, you have some way to measure how
much force is being applied right at that clamp head.
If you can equalize that, then looking at the bar deflection might
tell us some interesting as you'd probably want the ones
that deflect the least. But until we do that.
I don't think we can count those numbers as being meaningful,
but there's good news, my friends, most people are probably applying
more force than is truly necessary. When clamping the goal is
to simply close the joint. When the gap disappears
and you see some glue squeeze out, you can usually stop.
If you crank it. Beyond that point, you're only causing more deflection
in the bar and potentially causing the thing
that you're clamping to deform. So there's no need to go all He-Man
on it. Apply no more force than is necessary.
And chances are deflection just isn't going to be
that big of a problem. And that brings us to our final point
that perhaps, maybe possibly parallel clamps are not the best
choice for panels. Pretty much every parallel clamp review
that I've seen or read utilizes panels as some sort of metric
for the quality of the clamp. And the more I think about it,
the less relevant that seems to me primarily
because of points one and two that we just talked about. The heads
toe in and the bar deflects. So if we go back to a goofy drawing
here, now we can see when we have a three quarter inch panel,
let's say that isn't going to engage with the full height of the
clamps as you bring these in the toe in keeps the ends of the
panel down, right. So these are sort of being forced downward
here, pinched in place. And then of course,
the deflection happens and that is going to apply force straight
up. So, if we only apply a little bit of force
and a little bit of clamping pressure, we shouldn't have a problem.
But as soon as you really start to crank down on it,
you are absolutely going to end up with a little bit of a bow.
The amount of bow can depend on so many things.
But the most important one is how much force we're applying.
Of course, the thickness of that panel also plays a role
because the taller this piece gets, the more resistant to
that bowing it is. But if you have a nice thin half inch panel,
well, you could expect to see more of this bowing occurring.
So let's look at this in action with an actual panel.
So here I've got a three quarter inch white oak panel
and I'm going to drop a straight edge on there.
I don't have any pressure applied just yet.
Now, this is a four thou feeler, right? So you could see it's pretty
flat. I mean, we got a little bit of variation here,
but it's nothing big. So let's apply some pressure
and see what happens. Now that four thou feeler slides under there,
no problem. And this is a 16 thou feeler and I'm already getting
bored because feeler gauges suck. Ok. There's a gap there.
That's all we need to know. Mind the gap. Now the gap is pretty even on both
sides. And again, the wedge action of these toed in heads,
it's keeping the ends down while the deflection is raising the
center up. This is just what we're gonna see every time.
Now, this white oak board is not glued together.
I just have dominos in there just to kind of make it easier to
test. And I did test this board with pretty much every brand,
all 12 brands that I have here in the shop
and every single one of them will warp the board under pressure
just the way it goes. And if you do a thinner board,
which we have done, the thinner boards will warp more. Nature of
the beast. There's only so many things that can happen with this
type of situation. So does this mean that we are just sort of
doomed to have warped panels if we use parallel clamps?
Well, I certainly hope not. I've been using parallel clamps for
panels for a very long time. My work usually starts flat
and it stays flat, but you may have seen in my videos
that I often will alternate the direction of the clamps one up,
one down, one up, one down. I do that in maybe a slightly superstitious
way of hoping that it balances out the pressure.
I can't say that that's 100% true, but it seems to work for me.
So I continue doing it. You can try it, let me know if it works
for you. Now, all that said, I think we can relax a little bit
for two very important reasons. One is that woodworking has a
certain amount of flexibility built into it.
If you're making a panel that goes into a door frame,
let's say, and it's just slightly, maybe 1/16 or a 32nd out of
flat, it's not gonna matter. That panel is gonna go into the frame
and it's gonna be perfectly fine or maybe you're making a table
top again. Same thing if you've got a 32nd or 1/16 out of flat
on a table top, who cares who's even gonna notice?
It's just not a problem for most types of furniture.
And second, that panel that warped slightly under clamping pressure
might just go back to being flat once the pressure is taken off.
So here's a half inch panel that we made up yesterday,
thinner than that White Oak, which means under the same amount
of pressure, we actually saw a little bit more daylight on each
side, but we went through with the glue up,
we let it dry after it was dried, we just sanded it.
So it'll sit nice and smooth. Let's place it down on the surface
and see now that the clamping pressure is off of the panel,
what's going on. Now, just a reminder on the clamps,
there was a gap here and a gap here with a high point in the middle.
So what do we have? Now, a day later after the glee up,
there's a little bit of a gap in the center tightens up toward
the outside and then hits on the outside edge.
I mean, we almost have the opposite situation.
Got a little bit of a high point here and then another low point
there. So I think there's a real important moral to the story.
Wood moves. I mean, we say that so much it's almost become like
a punch line or a meme, but it's true wood will move on its own.
So the little tiny flaw that we might have stressed out about
and said, oh, these are terrible clamps. Look at
that little gap. This panel doesn't care after it was released,
it went back to what it was before and then it changed again
because that's what Mother Nature does with a natural product
like wood. So sometimes we're just spinning our wheels over nothing.
So if parallel clamps always deflect panels
and let's at least theoretically say that's a problem.
I think we just showed that most times it's not really a problem,
but we're going to pretend that it is and you need absolute flatness
in your panel. Well, there might be other options
that are better than parallel clamps. How about something like
this heavy duty beast? This is Bessey's I beam clamp.
It's, it's really heavy. I mean, it costs about the same as I
would say, maybe the average of the parallel clamps at like 45
to 50 bucks for a 24 inch model. But this thing is beefy.
It'll clamp the balls off a brass monkey. So I'm going to test
this white oak panel that we had before, put this guy in the clamps
and let's see what happens. And you really do have to be careful
with these things because they are strong.
I believe they're rated at about 7,000 lbs. So you probably could
break these boards if you really wanted to.
Let's not do that under pressure. This white oak panel is pretty
much dead flat. The clamp heads are toed in just like parallel
clamps, but the bar is so wide and thick that it isn't going to
flex nearly as much as a parallel clamp. But you do need to be
careful with these things because if you tighten them too much,
you will break the boards or cause them to buckle violently.
And Rockler recently released their deluxe panel clamps
that are specialized for panels, they actively keep your panel
flat while applying pressure from the sides,
which is pretty sweet, but they're obviously not as versatile
as a standard parallel or bar clamp. That's flat. So even though I've
been using parallel clamps to clamp panels since the start of
my woodworking career, clearly, there are other ways
that are a little bit better, but you got to spend more money.
You gotta collect a whole new set of clamps
and I'm pretty well stocked up on these clamps
and based on everything that I've told you so far,
I don't really see a reason why we shouldn't be using parallel
clamps for panels. But it's important to know
that if you're buying clamps today and just stocking up,
maybe you're just doing panels, maybe you have a cutting board
business. There are options that probably will be a little bit
better for you, but you just can't beat the versatility of a parallel
clamp. Now, I certainly don't intend to disparage anybody else's
reviews. Look, everybody has different opinions,
different ways of looking at things. This is just my opinions
and my thoughts on the topic. But when it comes to you guys spending
your hard earned money, I take my responsibility very seriously.
And if I see some things that I think are kind of taking you in
the wrong direction, I like to right those wrongs
and make sure you are armed with information.
So when you do pull out your debit card, hopefully not your credit
card. Thanks. When you guys go to spend your hard earned money,
you are actually getting the best bang for the buck
and the most reliable tools and materials
that you can possibly get so that you have better success as a
woodworker. If you buy something on my recommendation
and have rotten luck with it, I want to know about it
because I'd like to find out why. But I'm always trying to steer
you guys in the right direction with things like this.
So hopefully you found this useful and good luck purchasing your
next set of parallel clamps if that's what you buy.
Thanks for watching and happy clamping. My shoes are squeaky.