Thread: Kant clamp !

Hi BaronJ
Thanks for the file, but it will not open for me.
Bob

Here is the info i have. Not sure where i got it from.
kant_twist_clamp_plans.pdf
Kant Twist Clamp Assembly.pdf

snapatap,
Thanks for the pdf file, your version is the same as mine but the dimensions are much clearer on yours, looks like a swap is order.
Bob

Hi Bob,

I've just down loaded the file I posted. I'll up load it again right now.
Kant-Bob-1.dxf

(Edit)

I've just checked both DXF files that I posted and they seem fine to me. If anybody has a problem with them, please let me know. They are simple text files so they shouldn’t cause any problems. Any text editor should be able to open them.

Thanks:

Hi Guys,

Whilst I'm waiting to get the clamp side plates done, I've made a start on a few bits and pieces.
This is part No:4 Hinge "A" on the PDF that Snapatap and Bob posted. The dimensions are surprisingly similar.

02-09-2017-001.JPG 02-09-2017-002.JPG 02-09-2017-011.jpg 02-09-2017-012.JPG

This item started as a chunk of 22mm diameter round bar from the scrap box, turned to length and centered on both ends. I drilled and tapped for M5 X 12mm countersunk screws, which were shortened to 6mm. I made a number of brass washers to provide support and clamping for this part. I drilled through tapping size for M10 and threaded the hole. I'll finish of the pivot points when I get the side plates.

The idea of the brass washers is to allow the hinge to rotate whilst giving support to the top of the side frames.

02-09-2017-018.jpg 02-09-2017-019.jpg

I also made a little jig so that I could cut all the M5 CSK screws to the same length by clamping it in the lathe 3 jaw chuck and parting them off. This is just a bit of 10mm bar drilled, threaded M5 and counter sunk to match the screw head.

More bits later:

Hi Guys,

I've added a picture of a much larger kant style clamp. I'll leave it to the reader to drill any other holes if needed.
The big holes are 10mm and the small ones 6mm. The spacing between the side frames will be determined by the size of the screw used to close the clamp.

Please let me know if any other info is needed.

Thanks:
Kant-Bob-1.jpg

Hi Baron

Every Kant clamp that I have seen does not have the dog leg on it. I know you have done this to increase the clamping capacity. This will obviously increase the materials cost a little bit, probably not enough to really care about but do you know what effect this will have on the clamping force ?
My armchair engineering may be failing me but I'm thinking the greater the angle of the two parts with the screw (Hinge A & Hinge B) from each other would mean a reduction in clamping force as some of the force is trying to pull the two pieces away from the pivot rather then rotate them on the pivot.
Theoretically the screw pieces at 180 degree to each other would result in no rotation force and at 0 degree to each other would be the highest rotation force (translating in this application to clamp force). Anything in between is a combination of both forces. This means if the non dogleg version is say at 90 degree on fully closed and the dogleg version is 120 degree on fully closed the non dogleg version would generate higher clamping force as it would have a better ratio of rotational force vs pulling apart force.
What this would mean in the real world application I have no idea, but something to ponder as you may be sacrificing clamping pressure for capacity. If you don't use that capacity then they are just more expensive to make and less useful if you need the higher clamping force.

Kind regards
Wayne

Hi Guys,

I've made some more pieces for the clamp.

02-09-2017-004.JPG 02-09-2017-003.JPG 02-09-2017-017.JPG 02-09-2017-016.JPG

I cut some pieces from a length of 22mm diameter PVC bar then machined them to match the length of the "Hinge A" that I had made previously. After drilling 6mm holes through the middle, I press fitted a short length of steel rod through the middle, hacksawed so that about 4mm protruded from each side. These will form the spacers and supports to go between the side frames. Part "B" on the pdf. I've not yet decided how to secure them in the frame yet, I'm tempted to drill the ends and peen them in place or possibly a spot of weld.


02-09-2017-013.jpg 02-09-2017-014.JPG 02-09-2017-015.JPG

I did the same with the pivot pin, Part "B". But in this one I drilled for 8mm rod and also drilled right through and tapped for M5 from each end, before pressing the rod into the plastic spacer. I also used brass washers, countersunk for the M5 CSK screws.


02-09-2017-008.JPG 02-09-2017-009.JPG 02-09-2017-010.JPG

This Part is "Hinge B" Again made in the same way from 22m round bar, the ends turned to fit an 8mm hole, also drilled and threaded to take M5 CSK screws. I still have to make the brass washers and machine a flat on one side. I've run out of brass rod, so I will have to make a scrapyard visit later. I will cross drill 6mm clearance to suit a 6mm pin end on the clamping screw, which will also be threaded for an M4 cap screw.

If I get chance I will make some more bits today.

Thanks for your comments.

Originally Posted by MasterSpoon

Hi Baron

Every Kant clamp that I have seen does not have the dog leg on it. I know you have done this to increase the clamping capacity. This will obviously increase the materials cost a little bit, probably not enough to really care about but do you know what effect this will have on the clamping force ?
My armchair engineering may be failing me but I'm thinking the greater the angle of the two parts with the screw (Hinge A & Hinge B) from each other would mean a reduction in clamping force as some of the force is trying to pull the two pieces away from the pivot rather then rotate them on the pivot.
Theoretically the screw pieces at 180 degree to each other would result in no rotation force and at 0 degree to each other would be the highest rotation force (translating in this application to clamp force). Anything in between is a combination of both forces. This means if the non dogleg version is say at 90 degree on fully closed and the dogleg version is 120 degree on fully closed the non dogleg version would generate higher clamping force as it would have a better ratio of rotational force vs pulling apart force.
What this would mean in the real world application I have no idea, but something to ponder as you may be sacrificing clamping pressure for capacity. If you don't use that capacity then they are just more expensive to make and less useful if you need the higher clamping force.

Kind regards
Wayne

Hi Wayne,

Thank you for your comments, they are appreciated.

Yes you are right the dog leg does allow for a greater opening, increasing capacity. I freely admit that I gave no consideration to the clamping force at all. However now that you have caused me to think about it, I agree with your analysis of the direction of the forces applied. As you say what effect this will have in a real world application, I'm not sure either. I will have to give this some more thought.

From a cost point of view, I doubt that having a dog leg or not would make any difference. As far as changing the drawing goes, it is a minor detail. Its just a cut and rotate to remove the dog leg.

Hi Guys,

Not much to report at the moment, its been a busy day one way or another.

02-09-2017-021.JPG 02-09-2017-020.jpg

This is just 8" inches of M10 all thread, turned down at one end to 6mm diameter for about 20mm, then drilled and threaded for M4 to a depth of 12mm. I know that it is more than needed, but I might have to reduce the length of the turned section a bit. It depends upon how much play I allow in the "Hinge B" part. I propose to finish this part off by putting a M10 full nut on the far end and pinning or welding it, so that it cannot turn independently of the threaded bar.


02-09-2017-005.jpg 02-09-2017-006.JPG 02-09-2017-007.jpg

I've also made a start on machining the "Grip Blocks". This is a 120mm long piece of 1" inch square bright mild steel bar. I used a 16mm end mill to cut a "V" approximately 6mm deep, from one end to as far as I could get the table to go to the mill column. It will give me enough material to cut all the grips from it. I'll take some more pictures as I progress. The red ink used as layout dye, is just from a permanent marker pen.

That's all for now, thanks for looking.

Originally Posted by SurfinNev

If you don't mind, I'd like a copy to get a quote on water jet cutting.

can you keep us uptodate on costs to water cut...or for that matter anyone who gets a price to laser cut
i suspect qty will make each set cheaper. let us know..some of may be interested to make a bulk order?

Originally Posted by eskimo

can you keep us uptodate on costs to water cut...or for that matter anyone who gets a price to laser cut
i suspect qty will make each set cheaper. let us know..some of may be interested to make a bulk order?

Hi Guys,

Sorry for the delay in getting on with this project. Holidays got in the way.

I now have the eight pieces for the arms and frame for mine. Laser cut in 3mm plate they cost me £10.00p.

I'll post pictures later.

Hi Guys,

Some pictures as promised Also a surprise for me

My son collected the kant clamp parts that I had laser cut and also brought home three ER25 laser cut spanners, a gift from the Laser cutting guy.

01-09-2017-001.JPG 01-09-2017-002.jpg 01-09-2017-003.jpg 19-10-2017-000.jpg

Now to get on with finishing the rest of the bits and assembly.

Hi Guys,

Some pictures as promised Also a surprise for me

My son collected the kant clamp parts that I had laser cut and also brought home three ER25 laser cut spanners, a gift from the Laser cutting guy.

01-09-2017-001.JPG 01-09-2017-002.jpg 01-09-2017-003.jpg 19-10-2017-000.jpg

Now to get on with finishing the rest of the bits and assembly.

Hi Guys,

I've been slowly getting the kant clamps done.

21-10-2017-003.jpg 21-10-2017-009.jpg 21-10-2017-008.jpg 21-10-2017-005.jpg 21-10-2017-004.JPG 21-10-2017-001.JPG 21-10-2017-002.JPG

The above pictures show views of the clamps in various stages of assembly. I still have to make the jaws and fit a nut on top of the 10 mm threaded rod. The end that fits into the hinge is turned down to 6 mm and drilled and threaded M4 in the end to retain it in the bush. I also oiled all the mating and pivoting surfaces. When the jaws are made and fitted I will have 3.5" (89 mm) inches between the jaws.

21-10-2017-007.jpg 21-10-2017-006.jpg

In a previous post I showed cutting a "V" down this piece of 1" square bright bar, this is the other side. I'm cutting five 1 mm deep "V" grooves to form a gripping surface. I propose to part the jaws off after drilling a 6 mm through hole for the mounting pin, after which I will machine cross "V"s into the jaws. I haven't decided what to do with the third jaw face yet.

The red dye is from a red permanent marker pen, which I use as layout dye. I got a box of ten for £5.00p. Good value when you consider what is charged for lay out dye.


Thanks all for the comments.