# New Never-Twist clamps



## Brian26 (Sep 2, 2021)

This summer I have been designing and building my own version of Kant-Twist clamps in 3 sizes - 2.5", 4.5" and 6". I have the 6" one finished and will include pictures. I am happy with the design and have learned a lot from the process of building my first clamp. I had a decent quantity of the various arms manufactured locally, using a laser cutter, and this has worked well. Of special note is that the design includes all necessary holes - very precisely located to make the clamp go together accurately and work smoothly. I created a document with many more details and will attach that for anyone who wants to read the fuller story. This documents covers the flaws in the clamps I purchased, the major design goals of my re-design, the process of making the first clamp and some prices.

Happy to make available sets of the arms to anyone interested - details in the document attached. My thinking is that only a few of you would want to read 5 pages of details on this subject! But, for anyone interested, the complete story - so far - is in the attached PDF file.


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## Dabbler (Sep 2, 2021)

That is a great effort, and I've downloaded your PDF.  Looking forward to reading it tonight!


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## Janger (Sep 2, 2021)

Awesome!


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## Brian26 (Sep 10, 2021)

Just finished making some of the larger arms look nice, using a 1" abrasive pad. One new image shows a pair of the short arms - one as it comes from the fabricator, the other after using the abrasive pad. The second new image shows a complete set of the arms after treatment with the abrasive pad.


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## Mcgyver (Sep 11, 2021)

those look great, good job!  Kant and parallel clamps are the ones I use the most, you just can't have too many of them!


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## Janger (Sep 13, 2021)

Brian26 said:


> This summer I have been designing and building my own version of Kant-Twist clamps in 3 sizes - 2.5", 4.5" and 6". I have the 6" one finished and will include pictures. I am happy with the design and have learned a lot from the process of building my first clamp. I had a decent quantity of the various arms manufactured locally, using a laser cutter, and this has worked well. Of special note is that the design includes all necessary holes - very precisely located to make the clamp go together accurately and work smoothly. I created a document with many more details and will attach that for anyone who wants to read the fuller story. This documents covers the flaws in the clamps I purchased, the major design goals of my re-design, the process of making the first clamp and some prices.
> 
> Happy to make available sets of the arms to anyone interested - details in the document attached. My thinking is that only a few of you would want to read 5 pages of details on this subject! But, for anyone interested, the complete story - so far - is in the attached PDF file.



I've reviewed your pictures and the PDF quite closely now Brian. Post more pictures! Nice job. I have a few questions:

Are the peened standoffs holding the arm sandwiches together the only thing holding the arms on? I don't think there is any peening or anything else at the pivot parts with the threaded rod or the main pivot point? 
Related to this is the threaded hole standoff - it looks like it just rotates in the hole and is held in place by the clamp arms? Yes? 
The aluminium clamping pads are attached with clevis pins - in the pictures the cotter pin isn't visible. Did you use that kind of clevis pin or something with retaining rings? or some sort of chicago bolt setup? 
Is there a "quick" version of a kant-clamp where the threaded rod can be moved back and forth without turning for gross adjustment and then the nut engaged for clamping? Kind of a half-nut arrangement for kant-clamps? 
If you like I would make CAD PDF's for your 3 designs for you - we could post them on the forum for interested members.


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## Janger (Sep 13, 2021)

one more question - how exactly does the threaded rod mate with the end that pushes and pulls the arm? #10 screw ok with a bit of loctite holding it - I assume the screw is a bit loose and the buttom of the head pulls the clamp open? What about the pushing end in the block? Any lubricant in there ?


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## Brian26 (Sep 15, 2021)

Janger said:


> I've reviewed your pictures and the PDF quite closely now Brian. Post more pictures! Nice job. I have a few questions:
> 
> Are the peened standoffs holding the arm sandwiches together the only thing holding the arms on? I don't think there is any peening or anything else at the pivot parts with the threaded rod or the main pivot point?
> Related to this is the threaded hole standoff - it looks like it just rotates in the hole and is held in place by the clamp arms? Yes?
> ...



John
Insightful and, in the case of your No. 4 - most interesting! Here are some specific answers:
1. Yes - only the "standoff" pins are peened. All the rest need to rotate.
2. Yes - held by the peened standoffs. Note that my redesign has added an extra pin in each arm to make this a lot more sturdy than the original. This especially applies to the third point below:
3. None of the above! I took a standard, 2" clevis pin and shortened it to the right length. Then, when drilling the hole in the aluminum, I made sure to choose a drill bit that would result in an interference fit for the clevis pin. Then, just pounded it through! So, the aluminum block does not rotate on the pin, BUT, the whole assembly rotates in the holes near the ends of the arms. Cannot get loose because there is an arm on each side. Big plus: Easy to replace these pads if ever it becomes necessary. Just pound them back out!
4. What a great idea! That would save tons of twisting - especially when you use a 7/16-20 threaded rod like I did. We need to get our heads together on this. See below also:
5. I would welcome your help with this. I tried to learn EasyCad, but that is not going too well - there are so many basics to learn before you can actually do anything! I also tried using just Microsoft Word - and that has possibilities - but just 2-D of course. As it stands, my plans are, er, sketchy to put it mildly, but for the most part, understandable. Can I get these to you somehow - or, even better - bring them to Calgary? Send me a message outside the forum (or, call me...) and we will make this happen. I would be more than pleased to meet with you - or whatever you think is best.
Thanks for the informed and useful response. Cheers,


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## Brian26 (Sep 15, 2021)

Janger said:


> one more question - how exactly does the threaded rod mate with the end that pushes and pulls the arm? #10 screw ok with a bit of loctite holding it - I assume the screw is a bit loose and the buttom of the head pulls the clamp open? What about the pushing end in the block? Any lubricant in there ?


John
I turned down the threaded rod to 5/16" for about .750". Then, after turning the smaller diameters on each end of the "push/pull" part, I milled a flat on the "top" and "bottom" of the rounded section of the 7/8" steel rod I used for this part. Made the flats 180 degrees from each other of course. This left the distance between the flats at a bit less than 3/4" - so the turned-down portion protruded maybe .010". I made sure the 10-24 bolt would fit properly, then used my sander to shorten this turned-down part so it just barely clears the "width" of the flats. This is finicky of course, but it only took a few minutes. Net effect - there is very little "play" in this part of the mechanism - perhaps 15 degrees? I could get it closer perhaps - but then differences in the shop temperature might make it inoperable!

No lubricant in the other end, apart from what might remain after the lathe work. Could easily be added if it ever needed it. Another great idea! Cheers


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## Dabbler (Sep 15, 2021)

before you guys invest a lot of time and effort, have you heard of Dimide clamps?

The first 1"20" of the video is all you need to know.  They use left hand and right hand threads on that clamp, but with the drill-ready end, one could just use 7/16 ready rod to close them.  I think they are superior to KantTwist, but I have 8 KTs right now, so I'm not buying Dimide ones in the near future...






My take on an 'improved' no-twist clamp is a shape like the dimide, but with 1/2-13 ready rod, but with the Dimide ends for impact on one side, and a handle on the other.  The trouble with the Kant-twist, is the wierd shape,on  which the Dimide improves.  To save material, it could be designed with a stackable curve.   It's so simple to redesign, I wonder why more people aren't cloning that one(?)


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## Brian26 (Sep 15, 2021)

Dabbler said:


> before you guys invest a lot of time and effort, have you heard of Dimide clamps?
> 
> The first 1"20" of the video is all you need to know.  They use left hand and right hand threads on that clamp, but with the drill-ready end, one could just use 7/16 ready rod to close them.  I think they are superior to KantTwist, but I have 8 KTs right now, so I'm not buying Dimide ones in the near future...
> 
> ...



Thanks for alerting me to these great clamps. No doubt about it - stronger then the Kant Twist ones due to their change away from the cantilever design. Their direct-acting threaded rods must be what is responsible for their higher clamping force. Of course - you lose some high percentage of the clamping depth - so I think I will stay with the Never-Twist for now because I value throat depth more than closing force. But for some things, these will be hard to beat.


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## eotrfish (Sep 15, 2021)

The Dimide clamp looks a lot like this Starrett 1640. 164C
Great clamps that don't twist.





I have a few sizes from years back but it looks like Starrett no longer offers this clamp.  This one can't be used with an impact wrench since there is no hex on the adjustment knob, however the knob does have a hole for a tommy bar and a rotateable mounting stud (on the left).


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## Brian26 (Sep 15, 2021)

eotrfish said:


> The Dimide clamp looks a lot like this Starrett 1640.
> Great clamps that don't twist.
> View attachment 17125
> 
> I have a few sizes from years back but it looks like Starrett no longer offers this clamp.  This one can't be used with an impact wrench since there is no hex on the adjustment knob, however the knob does have a hole for a tommy bar and a rotateable mounting stud (on the left).



Couple of things. First, I wonder who owns the patent on these clamps, because this does indeed look a lot like the Dimede one. Second - it doesn't look as if this Starrett model has the quicker-acting left/right threads as does the Dimede? Great to know about this - thanks.


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## PeterT (Sep 15, 2021)

The Starrett looks like single thread, yes? That would be simpler to make all things equal. I like those button head screws for assembly & also to swap in different jaws pads.


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## eotrfish (Sep 15, 2021)

Yes - the Starret has a single thread.  I haven’t taken one apart to see if the sides are just aligned by the button head screws or if the screws are threaded into a step dowel.  It seems to be an elegant build - I’d expect nothing less from Starrett.


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## Janger (Sep 16, 2021)

eotrfish said:


> The Dimide clamp looks a lot like this Starrett 1640.
> Great clamps that don't twist.
> View attachment 17125
> 
> I have a few sizes from years back but it looks like Starrett no longer offers this clamp.  This one can't be used with an impact wrench since there is no hex on the adjustment knob, however the knob does have a hole for a tommy bar and a rotateable mounting stud (on the left).



@eotrfish what does the back of the clamp look like? ie what do the machine screws holding the clamp together attach to?


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## eotrfish (Sep 18, 2021)

Correction - the clamp I mentioned is actually Starrett 164C - not 1640
It looks like Starrett had this protected under two patents as stamped into the frame.




Janger - the button head machine screws attach to stepped dowels.




I also found when I took it apart that the rotatable stud actually has an eccentric which can be used to apply additional clamping pressure once the thread is tightened as far as possible.  This explains the internal hex - you can use an allen wrench to further tighten the clamp.

If you look up https://uspto.report/patent/grant/10,307,893 you'll get some insight into the Dimide adaptation of the Starrett clamp.  There are a lot of interesting drawings at the end of this patent.


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## Janger (Sep 19, 2021)

I got busy and designed up a version of the dimide in Fusion 360. This is about a 6" throat depth version.

I've been mulling over options on how the threaded rod would exert the clamping pressure. The area in red circle is still to be defined. I was thinking of using two locking collars on the threaded shaft - one on each side of the stand off - probably with flats or even holes going right through the threaded rod for a pin. Any suggestions on this? I see on the starett 164 there are two square blocks on the shaft. The one located on the threaded section is clearly threaded and moves back and forth exerting the clamp pressure. The closer one at the handle end though is not so clear what it is doing. It seems it must be fixed in place yet also allow the shaft to spin - @eotrfish how does that part work? Perhaps the knurled handle part presses on the square block and the rod simply spins inside the block? Is the threaded rod and handle all one piece? and thanks for posting that disassembled picture it's interesting.

Does the far end of the threaded section have a screw on stop?

I also like the standoffs are internally threaded and use machine screws for assembly. And the bend in the arms means you only need one length of standoffs and only one clamp pad depth - very clever Starett. (Edit -> well not quite looks like there are a few different lengths of standoffs) And I see the standoffs holding the clamp pads have a different head diameter - I wonder why they did that?


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## Tom O (Sep 19, 2021)

Probably one piece shaft there’s a shoulder and a circlip, pinned is also possible as no forces are in that direction.


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## Tom O (Sep 19, 2021)

Another thing you might consider is the clamp faces being flat like most clamps I think it would be useful to have a v cut in opposite the main gripping flat that way they could be rotated to hold round to flat or round to round without skating they could have a spring and ball locating the position keeping them in place. I would cut the v on both but at 90* to each other for 2 directions of holding.


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## kevin.decelles (Sep 19, 2021)

[mention]Janger [/mention] have you figured out a price yet? [emoji3]


Sent from my iPhone using Tapatalk


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## Janger (Sep 19, 2021)

Tom O said:


> Another thing you might consider is the clamp faces being flat like most clamps I think it would be useful to have a v cut in opposite the main gripping flat that way they could be rotated to hold round to flat or round to round without skating they could have a spring and ball locating the position keeping them in place. I would cut the v on both but at 90* to each other for 2 directions of holding.



Got it!


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## Janger (Sep 19, 2021)

Upgraded from peened rivets to screws. Screw models are from McMaster Carr.


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## eotrfish (Sep 20, 2021)

Janger

To confirm...

The handle end of the threaded rod is retained in the square block with a C-clip. 






The knurled handle presses on the square block and the rod simply spins inside the block.  You got it right.  The threaded rod and handle is all one piece. 






The far end of the threaded section has a stop washer which is retained by a C-clip.





I think your decision to opt for screws rather than peened rivets is a good one.  You can change the anvils to V / Flat / Radiused or whatever your heart desires in less than a minute.


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## PeterT (Sep 20, 2021)

The only other thing I'd suggest is how to size a graduated set, like small / medium / large for example. Looks like the width is about 2X the distance between pads & jack screw. So big clamps may not be appropriate for small jobs given the overhang. And when they are wide open you lose a bit of mechanical advantage. Some things may scale, other things (like fasteners, therefore threaded holes, jack screw... maybe even plate thickness) may be different for different sizes. I'm a 1-IKEA wrench kinda guy, but sometimes that's just not possible.


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## Tom O (Sep 20, 2021)

I was just thinking all these clamps just work clamping I think I’d redesign the frame so the jaws still rotate but has clearance on the outer edge so it could be used to spread / align your builds as most people don’t have a helper. Maybe just a drop in jaw.


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## Tom O (Sep 20, 2021)

PeterT said:


> The only other thing I'd suggest is how to size a graduated set, like small / medium / large for example. Looks like the width is about 2X the distance between pads & jack screw. So big clamps may not be appropriate for small jobs given the overhang. And when they are wide open you lose a bit of mechanical advantage. Some things may scale, other things (like fasteners, therefore threaded holes, jack screw... maybe even plate thickness) may be different for different sizes. I'm a 1-IKEA wrench kinda guy, but sometimes that's just not possible.
> 
> View attachment 17173


And that is probably why they were discontinued you could probably move the rod to the left of it like the can’t twist because the more you get to the pivot the less clamping force.
you could extend the arm to use the same system as the can’t twist.


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## Proxule (Sep 20, 2021)

Slick work Brian, THnaks!


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## Brian26 (Sep 21, 2021)

Janger said:


> I got busy and designed up a version of the dimide in Fusion 360. This is about a 6" throat depth version.
> 
> I've been mulling over options on how the threaded rod would exert the clamping pressure. The area in red circle is still to be defined. I was thinking of using two locking collars on the threaded shaft - one on each side of the stand off - probably with flats or even holes going right through the threaded rod for a pin. Any suggestions on this? I see on the starett 164 there are two square blocks on the shaft. The one located on the threaded section is clearly threaded and moves back and forth exerting the clamp pressure. The closer one at the handle end though is not so clear what it is doing. It seems it must be fixed in place yet also allow the shaft to spin - @eotrfish how does that part work? Perhaps the knurled handle part presses on the square block and the rod simply spins inside the block? Is the threaded rod and handle all one piece? and thanks for posting that disassembled picture it's interesting.
> 
> ...



John
Wonderful drawings. Very clear and helps me understand that this type of clamp does have a deeper throat when fully open - a big plus, providing you do not have to close it too much. Your red circle concern could be solved the way Dimede did - by using right and left hand threads. If that is not practical for some reason, then this is bound to be an area for concern, because of the tremendous forces involved. You could probably find a solution for up to one ton of force - but this design goes way beyond that, and so a hefty part will be needed here.
Regarding the threaded standoffs - it is a great idea, and the guy in Winnipeg uses that for his design. It is more fussy however and would take lots longer than peening the ends. Regarding peening, I wonder if your fantastic Fusion 360 designs could easily be modified to show a longer end on the 8 standoff pins? Or, alternately, leave them as is and add a threaded hole? Both designs would work well, and any maker would be happy with either choice.
Great work - and I like the way you think!
P.S. - I plan to take some more detailed pictures of the clamp I made and post them. Maybe later today?


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## Brian26 (Sep 21, 2021)

kevin.decelles said:


> [mention]Janger [/mention] have you figured out a price yet? [emoji3]
> 
> 
> Sent from my iPhone using Tapatalk


Kevin
I did not want to be too forward on this forum, so I put the prices in my PDF attachment. Let me know if I should send you that file separately, and I will gladly do it. Would need an e-mail address - it is way too large for a phone to handle I think. Cheers,  Brian


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## Janger (Sep 21, 2021)

Brian26 said:


> John
> 
> Regarding the threaded standoffs - it is a great idea, and the guy in Winnipeg uses that for his design. It is more fussy however and would take lots longer than peening the ends. Regarding peening, I wonder if your fantastic Fusion 360 designs could easily be modified to show a longer end on the 8 standoff pins? Or, alternately, leave



Brian
How far above the surface should the standoffs stick out for peening? 
J


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## Brian26 (Sep 21, 2021)

Janger said:


> Brian
> How far above the surface should the standoffs stick out for peening?
> J


John
I made my first one .060" - but that is too long I think. .040" should be about right.


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## Brian26 (Sep 21, 2021)

Brian26 said:


> This summer I have been designing and building my own version of Kant-Twist clamps in 3 sizes - 2.5", 4.5" and 6". I have the 6" one finished and will include pictures. I am happy with the design and have learned a lot from the process of building my first clamp. I had a decent quantity of the various arms manufactured locally, using a laser cutter, and this has worked well. Of special note is that the design includes all necessary holes - very precisely located to make the clamp go together accurately and work smoothly. I created a document with many more details and will attach that for anyone who wants to read the fuller story. This documents covers the flaws in the clamps I purchased, the major design goals of my re-design, the process of making the first clamp and some prices.
> 
> Happy to make available sets of the arms to anyone interested - details in the document attached. My thinking is that only a few of you would want to read 5 pages of details on this subject! But, for anyone interested, the complete story - so far - is in the attached PDF file.



More Pictures!


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## Janger (Sep 22, 2021)

Brian - how did you do the fancy ones finish? 

Everybody - if I made the standoffs from aluminum would there be any strength concerns? It would be easier to thread…


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## Dabbler (Sep 22, 2021)

aluminum would be fine.  the standoffs don't get that much stress...


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## Brian26 (Oct 2, 2021)

Janger said:


> Brian - how did you do the fancy ones finish?
> 
> Everybody - if I made the standoffs from aluminum would there be any strength concerns? It would be easier to thread…


John
To make the arms look like the picture, I used a 1" abrasive pad I got from Amazon in my milling machine - but any drill press will do this. These pads screw into an adaptor which you also need. I bought a package of 30 pads at once, and the first pad did all four arms, and still has life left. I free-handed the whole process, moving the arm perhaps 5/8" each time. Each "scratch" took only a few seconds.

Regarding the aluminum standoffs, I had not thought about aluminum - but it should work well. I think it would lower the strength a bit, but the savings in time might be worth it. One thing I do know from being almost finished making the second clamp (with the fancy-looking arms) is that it is a challenge to drill and tap a hole into steel for a 10-24 bolt. If I recall correctly, you intend to make a clamp using threaded ends on each standoff - an elegant solution I believe.


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## Brian26 (Oct 2, 2021)

Dabbler said:


> aluminum would be fine.  the standoffs don't get that much stress...


I think that aluminum would work very well if, like John you intend to drill and tap the standoff ends for small bolts to hold things together, and not use peening like I did. I think aluminum might be too soft for peening and so I did not even think of that. I now am thinking that brass might be better than aluminum? Very easy to machine, drill and thread. For the record, I have made the central pivot for my second and fancy clamp from brass. There will be pressure on this pivot point, but the diameters are large enough so it should not be a problem. We shall see...


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## Brian26 (Oct 2, 2021)

kevin.decelles said:


> [mention]Janger [/mention] have you figured out a price yet? [emoji3]
> 
> 
> Sent from my iPhone using Tapatalk


Kevin - Prices are included in the .pdf document I posted initially. Hope that helps.


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## Brian26 (Oct 2, 2021)

Busy yesterday and today making the "internals" for the second clamp. Ready now for the installation. I made the handle so that it slides this time around. Also used 7/16-14 threaded rod instead of 7/16-20 so the clamp will open and close faster. Have a look:


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## Tom O (Oct 2, 2021)

Looks good but I think it would be more comfortable tightening it with round caps instead of square ones.


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## Dabbler (Oct 2, 2021)

Nice work!


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## Brian26 (Oct 3, 2021)

Tom O said:


> Looks good but I think it would be more comfortable tightening it with round caps instead of square ones.


Tom - Great idea. I made a prototype using hex bar, but that seemed too fancy. I may knock this apart and try the round bar stock I have here - somewhere...


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## Brian26 (Oct 3, 2021)

Apart from making and fitting the pads, the second clamp is done. I may replace the square brass at the end of the handles as suggested by Tom. But first, the pads. I can now choose between copper, brass, aluminum and bronze - after an expensive shopping experience. I like the look of bronze, but something I read suggests it might be too slippery for pads? Any ideas? Anyhow - here are more images of the clamp fully assembled with no pads. I took some close-ups for those of you who are curious.


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## Proxule (Oct 5, 2021)

Very sexy work brian, keep it up!


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