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Making "Kant" Style clamps.

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BaronJ

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#1
Hi Guys,

I know that some of you like projects, and tools ! So I thought I would do a little write up on how to design and make your own "Kant" style clamps.
These clamps are quite unique in so much that they behave very much like a vise. Unlike an ordinary "G" clamp they don't twist when being tightened up, in fact they can exert two or three times the force than can be achieved with a "G" clamp of the same size.

The design is quite flexible. You can make them from various materials, I made mine from steel plate, you could use aluminum or brass, or even plastic sheet material.
This project requires some turning and threading, but little else.

Kant-01.jpeg


The picture above shows the basic layout of the Kant clamp. Notice that all the holes fall on the diameter of two concentric circles.
In this drawing the circles are 22 mm apart. To make larger or smaller clamps just scale the circles. The Odd hole is for a spacer.
You will need to turn this spacer down so that it clears the screw when the clamp is fully closed. The other spacer fits in the knee of the longer side piece.

01-09-2017-001.JPG

This is a picture of the side frames made according to the drawing. The pivot holes, larger ones are 8 mm diameter and the small ones 6 mm diameter.
You need two of each for each clamp. These were made from 3 mm laser cut plate. The original ones were cardboard templates.

02-09-2017-002.JPG

The nuts for the screw was a simple piece of turned bar with a M8 threaded hole. You need two of these nuts. The spigots on either side were turned so that they fitted into the 8 mm holes in the side plates. You can set the spacing between the side frames to what ever you like as long as you have room for the clamp screw.
I drilled each end and threaded for M5 CSK screws.

You also need to make some spacers. I made mine from PVC bar with a short length of 6 mm steel rod pressed through and pressed into the side frame. The laser cut holes were a quite tight fit on the 6 mm rod. But since they are only there to support the side frames it doesn't matter.
02-09-2017-003.JPG

At this point I'm going to take a meal break. I'll continue later.
 

BaronJ

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#2
Hi Guys,

This is a dimensioned drawing, showing the hole sizes. I said previously 8 mm diameter, it should have been 10 mm. Sorry about that. Its only just over a year since I made these.
Kant-03.jpeg

I used M5 counter sunk screws to hold both threaded nuts and the side plates together and made brass cup washers to support the CSK screws.
The central pivot was made from 10 mm round bar drilled through and threaded M5 from both ends before pressing it into a PVC spacer.
02-09-2017-013.JPG
All the cup washers were turned from bits of brass scrap picked up at the local scrap yard. They were drilled 5.25 mm in the lathe, then placed on a mandrel and turned to 10 mm diameter. I had several bits of brass of different diameters and different lengths. When they were all the same diameter, I put them in the chuck and countersunk the end to the depth of the head of the screw, just under 3 mm and then parted off slices of three millimeter long. Countersunk the next one and did the same again. I did this until I had 24 washers.

02-09-2017-015.JPG

02-09-2017-012.JPG
These are the completed spacers and nuts.

At this point you should be able to test fit everything together. The side frames should be a close fit on the pivot points and have very little play.
I said earlier that the nuts were drilled and threaded M8, these nuts were drilled and threaded M10. Which ever size one you use, the bottom anchor will need to be drilled to suit the threaded rod machined end size.
02-09-2017-020.JPG
This is a picture of the threaded rod used to operate the clamp. The end is turned down so that it is a loose fit in the bottom nut. The turned end is drilled and tapped M5 for the screw that is used to retain it...

I'm going to take a break here. Thanks Guys.
 

Canus

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#3
More dimensions please.
 

BaronJ

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#4
Hi Guys,

Right let me continue.
02-09-2017-021.JPG
This a picture of the end of the screw, the part that runs in the bottom bearing, showing the M5 thread in the end. The CSK screw that goes in here is the retainer for the clamp screw. There is very little force on this screw, it only has to pull the clamp open. The top of this turned down section is a square shoulder. This shoulder takes all the force from the clamp screw when closing the clamp. I did put a thin brass washer on here to prevent binding, which it does well.

21-10-2017-004.JPG
This picture shows the amount that this clamp will open, about 5,3/4" inches without the feet. Also the layout of the parts inside.

21-10-2017-005.JPG
This is just an anotated close up of the clamp screw, the nut and the bottom bearing for the screw. The spacer acts as a stop when the clamp is fully open and just clears the clamp screw when fully closed. There is a countersink in the bottom bearing that the CSK runs in. When the length of the machined part is correct, the clamp screw and the retaining screw have very little play. The head of the retaining screw is hidden just inside the edge of the bearing.

Before I move on, just a word about dimensions ! Very few are really critical, I know of people that have made clamps to my design that have jaws that can hold large 12" inch plus, items. However if you get stuck, well you know what they say ! There are no silly questions, just ask.

I'm going to start a new post covering the clamp jaws and how to make those.
 

thomas s

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#5
Nice job on the clamps. And thanks for the write up.
 

Bi11Hudson

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#6
No comment up or down... It looks good and I appreciate the effort. I may even make a few "small" ones, for my model building. Never have enough clamps and this type has gotten rather costly. Thanks... ...

BTW, I like the penguin. Look into www.hudsontelcom.com for some "sea stories" about (real) penguins.
 

savarin

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#7
Very nice write up but now youve given me another "must do" project :beer:
 

Jubil

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#8
Great write up. Another one on my project list. Can't wait for the rest.
 

tcarrington

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#9
At the risk of stealing a design, the dimensions for all the commercially available clamps of this type are available on line. If you search you can find all sizes, some in metal some in wood. From what I have seen, it is looks right, it probably is right. (I stole that quote from someone). Seems to me the greatest amount of effort will be getting the sheet metal cut out and ready for assembly. The turning and drill / mill work look easier.
 

BaronJ

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#10
No comment up or down... It looks good and I appreciate the effort. I may even make a few "small" ones, for my model building. Never have enough clamps and this type has gotten rather costly. Thanks... ...

BTW, I like the penguin. Look into www.hudsontelcom.com for some "sea stories" about (real) penguins.
Hi Bill,

The clamps are quite easy to design and make !
I'll do some notes on the design method.

PS. Thanks for the link.
 

BaronJ

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#11
Hi Guys,

Thanks for the votes of confidence. :)
In this part I'm going to cover making the jaws. Apart from drilling some holes the jaws are all milling.
21-10-2017-007.JPG 21-10-2017-006.JPG
The piece of steel bar was just long enough to get all eight jaws out of. I scribed five lines down the length, about equidistant and cut grooves with the corner of a 16 mm end mill. By using a "V" block to hold the work and it being just high enough to clear the top of the vise, I moved the cutter 1mm in and 1 mm down, traversing by moving the table forward (towards the handwheel). The cuts don't go right to the edge because the table wouldn't go any further back and I wasn't going to start moving the vise.

26-10-2017-002.JPG 26-10-2017-004.JPG
I just turned the workpiece over to put a single wider groove down the other side for the purpose of being able to grip round work. I left one face flat an did the cross groove after cutting the bar down to the sizes needed to fit inside the clamp frames. I did those four at a time because that was all I could support on the "V" block.

I don't have a DRO on the mill and it is quite plain to see where I miscounted the mill handwheel divisions. However it doesn't alter the utility of the jaws. All the jaws were drilled and faced off using the lathe four jaw chuck and tailstock drill.

I had considered making all the jaws the same width and cutting a radius in the sides to accomodate the end of the side frame, but discounted that because if I had then I would not be able to rotate the jaws.

26-10-2017-001.JPG
Wondering around in the local scrap yard I found several of these 30 mm by M10 X 1.5 mm long nuts. So I decided to use them on the end of the clamp screw and trim the end where it came through the nut. This picture was taken before I super glued the nut to the clamp screw end. They are now drilled to take a 3/16" "T" bar.

I was going to post a picture of a completed clamp, but it seems that I don't have one. o_O

Dinner time now, back shortly.
Thanks all.
 

Groundhog

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#12
Good idea - great post!

Thanks.
 

BaronJ

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#13
Hi Guys,

A lovely Sunday roast pork dinner. Traditional Yorkshire !

I said earlier that I would write some notes about designing your own clamps to suit what ever size you need. I also mentioned that all the holes bar one, lay on two concentric circles. Like many of you I have also looked at some of the designs on the web, and there are many ways of achieving the same end. This is just how I went about it.

I decided how wide and how deep I wanted the jaws to encompass. I also noted that from the central pivot point down to the jaw was the same for both legs. That led to the two circle concept.

Kant-Bob-2.jpeg
This is a drawing for a larger clamp than the one described but is just being used to show the concept.
Once you have decided on the jaw opening and the depth that you want. Using the pivot point as the center, scribe a circle going through the knee point. This circle describes the depth of the arm. Extending the from the knee to the jaw pivot gives you the width of the jaw opening.

Kant-03a.jpeg
The clamp screw will go from the knee on the "L" shaped leg to the top of the long leg, remaining on the circle. In the drawing above you will notice that there is a bend in the long leg. If you can now imagine the upper part of the long leg with the jaws at full opening, the upper part of the leg will foul the short leg. So by rotating the upper part away from the "L" shaped leg will increase the amount of clearance.

Apart from that deciding upon material, thickness and width will complete a design for almost any size clamp you want.

I'm quite sure that I will have made errors or forgotten something, so if you spot one let me know.

Thank you for looking ! Your support is much appreciated.
 

BaronJ

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#14
Hi Guys,

I would like to see your pictures and hear your comments about the clamps you make to my design or otherwise.

Thanks all.
 

Canus

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#15
Is there any way you can save your graphic files in another format? These seem to be jpg files which dither the edges and the dimensions are extremely difficult to read. I have had the best luck using either 16 color bmp or tiff. Really appreciate you taking the time to provide this valuable information. See attached drawing.
 

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BaronJ

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#16
Hi Canus,

Can you use a DFX ?
 

Canus

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#17
Don't have software that can open DFX files. Sorry.
 

BaronJ

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OK. What operating system do you use ?
 

Canus

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#19
Windows 7.
 

BaronJ

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#20
OK, I assume that you don't have any cad software ! I use "Qcad" and have done so for a number of years.
However I do not run any Windows software at all and haven't done since about 1991 or 2.

Go here:
https://qcad.org/en/download
There are two variants, one for 32 bit Windows and one for 64 bit Windows.
Download the one that suits your machine.
Qcad is free for personal use. There is also Qcam, which I have but not used.
Try it and see what you think. It will read and write DXF among others. Just remember that this is a 2D cad program.
 

BaronJ

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#21
Hi Canus,

Did you take my advice and download Qcad ?
If so have you had a play with it yet ?
 

Canus

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#22
Downloaded it but can't make hide nor hair of it. Will try to find something on line that provides instructions. Have used simple cad type programs in the distant past (mid 1980s DOS based) but am lost with Qcad.
 

Canus

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#23
Based on your avatar I assume you are running Linux.
 

BaronJ

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#24
Hi Canus,

Yes you are correct. I've run Linux since around 1991 - 2. The last windows version I used was 98 ! Even then it was a pain.

Qcad is not difficult at all ! OK some bits can be confusing, but that applies to any software. Can I assume that you have installed it and it is running OK on your machine. If you want we can take this off the forum and use PM, or continue here.
 
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