New Bessey K Body Revo - added force?

[Will Blick]

> have you tested 3/4" Pony clamps with black pipe?


No, I don't have any Pony's, but my guess is, with black pipe, they perform very well.... the softer the pipe, the less the slippage...and if they have the T handle, you can really get max. force, 1200 lbs.



> I don't think it makes sense to ask why we need to clamp hard, in a thread comparing clamping pressures.


Thank you for this :-) It seems whenever you offer info on clamps, the immediate question is, why clamp so hard?? I tried to difuse it early in the thread...but.... but here on the creek, everyone is civil, so no biggie.....



> Even if we all used spring clamps for everything, I would still be interested in the relative clamping pressures of different clamp styles, especially since some advertisers are using these claims as a selling point.


Exactly..... that's the point here.... I just want to understand what the heck I am buying? I consider a clamp that can easily reach 1200 lbs of force, to be more valuable than one that can only achieve 600 lbs. Regardless how I use it...


IF the Stanley Bailey parallel clamps could be joined, like the Besseys, I would use them exclusively. Its amazing how they entered the Parallel clamp game so late, and yet, produced an amazing product at a fair price. But I can't deny the value of being able to join the Bessey K's for those few occasions where I need long clamps. The Jets can be joined also, even though not advertised... as such... although i have not done it..... there was a thread here awhile back showing such....


Also, if you build up the handle on any of these clamps, you can add about 25% max. force you can achieve to the clamp. That was a very interesting finding....and it proves why the Stanleys are so damn good, not only is there handle triangular to prevent slipping, the handle is massively thick compared to the rest of these makers. hence why the Revos new handle dissapointed me. They missed both of these Stanley handle enhancements.


I built my K's up with some grip wraps that LV sells, as well as some close-out tennis grips, which work great for $1 each. I build the handle diameter up about 30 - 40%... I marvel how the damn gauge moves up 25% in force... makes me feel stronger ....oh yeah, easier on your skin too....


Interestintly enough, as robust as the Jets are, they too fall way short of their advertised pressure claim....some of my jets I can only push to 650 lbs, others to 800 lbs. I think their threads are not consistent, poor QC. The K's are more consistent.

[Brent Smith]

As for invisible glue lines, this is often a function of how long the glue joint is, and how straight the joined edges are.....which is where elapsed time since milling comes into play.... So there is many variables at play here. If the joint line is 4", even lousy jointed edges will join well, but not true when you have a 60" glue line. hence why i keep saying, the right clamping strategy is a mix of good ol fashion common sense combined with the available knowledge.

No argument from this corner of the peanut gallery .

[John Gornall]

Recently I had a large number of items to glue up - glued and clamped every hour for 3 days. Using K bodies my hands were in rough shape after. Funny how the work gets so important you don't notice the physical damage as early as you should - just gotta get the work done. Then yesterday I was gluing up a garden gate with a series of 14 large mortise and tenon joints. I had done a dry fit and all was smooth but in the final assembly with glue as happens now and then it just wasn't pulling together. My hands were hurting on the K bodies. I removed the K bodies and laid on the good old pipe clamps pulling the gate together easily. Now I'm looking at the K bodies and thinking about removing the wood handles and welding or pinning on a nut so I can use a ratchet wrench. I could also make a screwdriver handle with a socket for basic tightening. Those wood handles on K bodies are not good and hard on the hands.

[Will Blick]

> Those wood handles on K bodies are not good and hard on the hands.


Nothing like repetition to expose the weak link in the chain, huh? If you want to replace the handle, use the pipe clamp method, way easier on the hands and you get almost 2x the force from the clamp.... I can't fathom why the parallel clamp makers did not copy the pipe clamp handle design.... the force comes from leverage, vs. grip strength and ripping the skin off the inside of your hands....which when you do it a lot, can be irritating


Even though the Stanley Baily has the primo grip, it is NO match for the pipe clamp leverage handle..... let us know what you do! I have been too lazy to consider replacing the grips...

[Ron Dunn]

Do we care?

All I want to do with a clamp is hold stuff together while glue dries. I'm not trying to turn carbon into diamonds!

[Will Blick]

As mentioned, clamp pressure brings out the hecklers.... they can't resist.

Question: If you don't care, why are you reading the thread? Thats the real qustion!!!

[Ron Dunn]

It was a serious question. I'm curious about the woodworking circumstances in which this could be considered important.

I'm sure I've heard that too much pressure is as bad as not enough.

I'm also thinking of the woodworkers in times past, when joining a panel was by rubbed joints, with no clamps at all.

[Will Blick]

> I'm not trying to turn carbon into diamonds!

that certainly did not seem sincere to me?


Ron, if your questions was sincere, the answers are all above in this thread.... they have been repeated at least 5x now. Often, rubber bands will suffice for clamping pressure. Rubber bands will not turn carbon into diamonds.


However, that does not dismiss the need for clamps in some critical glue ups. At such time, it pays to understand how much force the clamps you use can apply.... assuming you want to follow manufacturers recommendation for max. hold and / or invisible glue lines.

[Ron Dunn]

The QUESTIONS have been asked, but the ANSWERS have not been forthcoming.

Is there any circumstance where over 800 pounds of pressure is necessary for a woodworking joint?

Sometimes obsessing over a detail obscures the fact that the detail is irrelevant.

[Will Blick]

> The QUESTIONS have been asked, but the ANSWERS have not been forthcoming.


AS mentioned Ron, it's all written in this thread.... getting tired of writing the same thing over and over.... ONE LAST TIME....


> Is there any circumstance where over a thousand pounds of pressure is necessary for a woodworking joint?


I think you are missing the connection between the pressure (force) vs. psi at the glue joint. Simple example....if you follow the guidelines for max. glue holding force and /or invisible glue line, you need about 200 psi at the glue line. If the boards are 1" thick, and 48" long, this is 48 sq in. of glue line. 48 * 200 = 9600 lbs of total force required. If your clamps "CAN" hit 1000 lbs of force, 9600 / 1000 = 10 clamps required. So in this example, you can safely use up to 9600 lbs of force. Is this mandatory? Of course not....it's suggested for max. holding force of the joint and / or an invisible glue line....



> Sometimes obsessing over a detail obscures the fact that the detail is irrelevant.


Glue makers and wood researchers spend millions of dollars obsessing over these details....they provide their findings to us for free. Whether a ww wants to implement their suggestions is a personal choice. Commercial shops that have pneumatic clamping systems which can provide a wide range of pressure.... they have to set their clamp pressures on the machine, this is an example how they determine such... OK? Irrelevant? Maybe to you and me, however, others do take heed to what manufacturers suggest.


I predict this will not be the end of ....

Why so much pressure questions.... arggggg....

[Tony Zaffuto]

Will, please don't take this as "heckling" as it is certainly not meant to be. I understand the need sometimes to have sufficient pressure to wrestle a couple of pieces together.

My issue, however, stems from the later reaction of the wood and glued-up joint, to that action. I am not denying one bit that sometimes you need all the force you can muster to close up a joint--I have had those occurrences, for example when a glue-up does not go according to plan.

My thoughts are that more attention needs to be made to prepping the assembly to prevent later reactions to the piece six months or a year after finish has been applied and it goes through the first temperature/humidity change in its final resting spot.

Now with this post, I will return to my knuckle-dragging brethren in the hand-tool sections. You guys need to visit some of those sites to see what real heckling is (certainly not done by me!).

Tony Z.

[Will Blick]

Tony, this post is certainly not heckling.... and it raises some often overlooked issues....


> My issue, however, stems from the later reaction of the wood and glued-up joint, to that action.


Interestingly enough, when speaking to a titebond engineer / chemist at a ww trade-show, he mentioned.... the most overlooked reason to attain max. glue adhesion (through sufficient clamp pressure) is to prevent wood movement from opening the glue line. He suggested, more often than not, the biggest load on a glue joint is wood movement, NOT mechanical loads placed on the joint. Which is what most of us think of...

A few years ago, this changed my mind-set from, "just glue it" ...to.... "glue it right" Of course, I get sloppy at times...but if the work piece is important, I give the glue line more attention.


> My thoughts are that more attention needs to be made to prepping the assembly to prevent later reactions to the piece six months or a year after finish has been applied and it goes through the first temperature/humidity change in its final resting spot.


Can you share some of these tips? I think NOT enough information is provided in this area.

[Rod Sheridan]

I normally use the K body clamps for glueing, however I also have many Jorgenson pipe clamps.

With hardwoods, I tend to use fewer clamps per joint, since the wood is stronger and resists crushing better. I can tighten the clamps up very tight, and achieve good clamping pressure by using fewer clamps, applying more force per clamp. This is significant, since I can use less clamps per piece, I just need to be able to apply more force per clamp.

With pine, I use more K bodies along the joint, and don't tighten them up as much. I get the same pressure by using more clamps with less force.

Since I am probably below median strength for an adult male, I wish that Bessey made a better handle for their clamps, so I could take full advantage of their clamping strength. Otherwise, I think that they are the best clamps I own.

P.S. When my FIL worked in industry, the panel glue ups were performed in a rotating panel clamp jig. The number of clamps, and the torque applied to the clamp screw was calculated, and the clamps were tightened with a pneumatic torque wrench. This was part of the work sheet information for the panel assembly. Even 30 years ago someone was thinking about clamping pressure. I was pretty impressed seeing that.

Regards, Rod.

[Tony Zaffuto]

Will,

You asking the wrong person (a hobbyist) for tips! There are things I do, but these I have learned from listening and watching others.

A few things I do, is make sure wood I am using is fully acclimated to my basement shop before using. For example, I'm working on a side table and the cherry I'm using has been in my shop for over six months, after being supplied to me kiln dried. I have the 1/2" poplar for drawer sides and bottoms also acclimating. Further, I usually only use quartersawn or rift sawn wood for table tops. Beyond that, I just try to apply good joinery--not sloppy joints, but also not joints that I need a ton of pressure to close! I also usually use a sprung joint for table tops.

In the past, I have observed movement in a few pieces I have made and that is the reason I'm sensitive to this issue. You made a very good point about glue strength too: often times the glue joint is far stronger than the wood itself. With wood movement, then, a crack can occur in a location away from the glued-up joint splitting the wood!

In closing, I may have missed the intent of this thread as purely a discussion of relative clamping pressures and to other posters, I apologize for that. Now as a "knuckle-dragger" I may be inclined to heckle a bit using some other verbage, such as asking why you power guys just don't resort to using hide glue and rubbed joints? You may not even need a clamp then!

You all have a good one said while ducking and running, and if you're going to through clamps my way, make sure they are (two) 72" alumimun made by Universal Clamp Co., as I got to do a glue up on the side table I'm making in a week or so.

T.Z.

[Scott Pearson]

When I saw the new Revo clamps I wondered why they did not do more to change the handles. Making the diameter of them wider or even changing the shape to a rounded triangle would have added more torque allowing for clamping pressure.

I stocked up on the big Bessy sales, I guess I should look for a few more.

Scott