Bessey K Body Revo Clamps Not Square?

[Stevedave]

Hello,

First time posting here as I've only been woodworking for a couple years at this point and could use your guys opinion on something.  Up until now I have just been using f-style and trigger style clamps because I've slowly been saving up for one tool at a time.  I finally bought myself my first two parallel clamps today because I plan on building a proper workbench and dining table this spring, so when I went to my local Woodcraft I ended up going with two 40 inch Bessey K Body Revo clamps.  I was also eyeing up the Jet parallel clamps and would have bought one of each to see which I liked better but they only had 24 inch Jet clamps in stock.  So I went home with two of the Besseys and at first was really happy about the choice.  I'm building a saw bench right now so I used the clamps to glue up some pieces of white pine to make the legs, and I noticed that I was seeing the one clamp made contact across the whole surface of the wood and the other clamp left about a 1/16th inch gap at the top no matter how much I tightened.  This uneven pressure was causing the wood to shift in the clamp.  I figured at first it was user error, but I know the pieces of pine were jointed square, so I thought maybe I tightened disproportionately, so I tried again but I couldn't get rid of the gap.  I took a square to the clamp and realized that the fixed part of the clamp wasn't square to the bar, but on the other it was square.  I took the clamp back to Woodcraft and you could tell at first the salesman was skeptical of what I was saying, but when I showed him a picture he took another 40 inch clamp off of the shelf and it had the same problem, not square to the bar.  I couldn't tell if I was being over critical and if at this point I just looked crazy because he still seemed skeptical, but when he took the clamp to their workbench you could see that the fixed part was slightly tilted outward on the flat bench top, and when he clamped it he could see the gap I was talking about.  This was on both the clamp I brought back and the one in the store, so he took a third one down and luckily this one was square to the bar, proving my point that the others weren't clamping right.  You could tell at this point he started to believe me and acknowledged how it would clamp unevenly.  I asked if they were going to say something to their Bessey rep because to me for a clamp that costs this much, I don't think you should have to worry about it not clamping your work properly.  I already saw that it was making clamping two pieces of pine together difficult so I can't imagine a 30 inch table top.  I wanted to get your guys opinion on this since these are my first set of parallel clamps, and wondered if any of you ever ran into this problem.  I attached pictures showing the difference between the clamps that are square and the one I took back that was off like the other one in the store.  In the one picture you can see how the clamp is out of square compared to the other, and in the other picture how the square clamp is making full even contact, but with the other you can see the shadow left from the 1/16 in gap from the uneven pressure.  If half of their inventory of 40 inch clamps were like this, to me it seems like this could be a big problem, but I don't know if I am being over critical or if this really in a manufacturing issue.  Any input you guys have is appreciated.

Steve

[Chet]

I have 8 Bessey Revo Jr's 4 - 18 inch and 4 - 24 inch and about 24 Jet ranging from 12 inches to 40 inches.  After reading you post I went a check about a third of them with my engineers square and the all had a gap but it was opposite of yours, it was at the bottom and maybe a 32th of an inch at the most.  I have never had an issue them during a glue up.

I am glad you got it squared away with the store and I am not trying to say that you were wrong because the clerk found the same issue but a speed square isn't the most accurate tool when checking something like this for square and I would be a little suspect of resting the square on the black plastic feet instead of the metal bare of the clamp.  There was a problem but these are two things that may make it look worse then it was.  Although not working properly is still the problem.

[Coop]

I’m not familiar with those clamps so just asking. The black stands that the clamps rest on, will they slide away from the end of the clamp to enable you to rest your square directly on the bar? Just wondering if the black stand is your problem. 

[Stevedave]

@Chet

@Coop

Thanks for your help.  I figured the speed square wouldn't be an an exact way to gauge how square the clamp is, but used it to show what I was seeing when gluing up.  I also have an engineers square that I was getting the same result with.  And I considered that the plastic feet could be the issue, but I got the same result using the bar alone as a reference, just couldn't balance the square on the bar to take a picture.  I'm hoping maybe this is a one off incident.  Maybe just those couple clamps were defective because the other two I bought are clamping squarely and evenly.  I just figured I'd see if this is an issue known to Bessey clamps since I'm going to be needing to buy a bunch more parallel clamps in the future.  Thanks again for your input.

[Chestnut]

Welcome Steve. I'm not sure if all of my clamps are square but that isn't a bad thing to check. I know some of mine are out of square the opposite way and this is intentional. The bra flexes a little bit so the manufacturer stacks things in your favor. It was smart to return that one, being out of square in that direction would cause problems as you tighten the clamp.

Keep in mind that a good best practice is to use an equal amount of clamps on opposing sides of the  pannel glue up. Say if you have 3 with the bad under neath it's good to have 3 with the bar on top.

2 minutes ago, Stevedave said:

I figured the speed square wouldn't be an an exact way to gauge how square the clamp is

I usually do a rough check by sliding the jaws together. There is a chance that someone bought the clamps over tightened them and then returned them. It may not be bessy's fault. They could have also been dropped.

[legenddc]

Nothing to add here @Stevedave besides look at HomeDepot for the Bessey clamps. They seem to have the 24" and 50" ones cheaper then anywhere else. Right now I'm seeing $52 for the 50" one and $42 for the 24" one.

[gee-dub]

Not much additional value but, I just checked a random selection of my original Bessey K-Body clamps of different lengths.  None showed any toe-out when using the bar as the reference.  Even the Groz clones I have that were popular for a while when Bessey first stopped the K-Body offering all checked out fine.  There have always been a few things that will slip by QA.  As with almost everything I buy today I would be selective and not trust to the brand or the paint to assure a quality product.  More than ever it pays to be an educated consumer. ;-)

[JohnG]

I went to use one of my bessey clamps a couple days ago, and suddenly my shelf was not sitting square and tight in my case. Took the shelf out, fiddled a bit, and then the gap was on the opposite corner! (I had ended up reversing the orientation of the clamp)

Mine was out of square by about the same amount shown in OP’s pic. Grabbed another off my wall and it was correct- just slightly out of square in the opposite direction.

I was in HD yesterday and took one of their nicer speed squares over to the clamps and one of the four 24” clamps they had on the shelf was like this. I’ll be sure to check them before I buy them in the future. 

[Cdlong]

So I went to check mine, I have 2 50" clamps. The faces on each clamp are both parallel to each other, but not the bar, and both clamps are the same.  The fixed end leans in to the bar, maybe 1/16", and the adjustable end leans in the same amount, the same direction (away from the bar in this case). Should I check into replacing them?  I'll have to go to the local big orange box to see if they have any better ones.

[Stevedave]

Just to follow up, but I went back to the Woodcraft where I mentioned I bought the Bessey clamps that were out of square, and the guy who had helped me told me that he actually did contact Bessey and their reply was that it is a QC problem they're aware of.  That they know of a batch of clamps that have this issue.  Definitely helps me feel validated and not crazy.  He also said that they also mentioned that what caused the problem was fixed, so hopefully any new batch of the K Body Revo clamps will not have this issue.  I needed a couple more clamps anyway so we used a square to double check, and we did see that some were square and some were not but this was still stock from the old batch.  So from what I was told it is definitely a good idea to double check because I saw a few that were even more out of square than the ones I originally returned.

[Mark J]

You'd think Bessey would be doing something to pull the bad batch off the shelves.

[G Ragatz]

41 minutes ago, Mark J said:

You'd think Bessey would be doing something to pull the bad batch off the shelves.

Not sure if they would have the data available to do that.  "Lot tracking" is a big deal in the food industry and in pharma, for obvious reasons.  Also in automotive and aviation.  Not so sure about something like clamps.  Bessey may not have very good information about where the bad batch of clamps ended up.

[Maciek]

I have the same problem only the deviation is in the opposite direction. At first I thought it was it was supposed to compensate for the deflection of the clamp rail, but Bessey writes everywhere that the jaws are perpendicular do the rail. For me, this disqualifies the clamp, because I often need to glue small and delicate elements with a single clamp, so I can't use washers, or opposite clamp and similar solutions.
That's why I bought full-surface clamps from a good company so as not to play with some washers.