Post by nickw on Jan 26, 2008 18:50:53 GMT
My UniKlamps have recently started to loose their grip - it seems that a few years use in a professional shop is too much for them, (either that or I'm just too ham fisted) and the wear on the heads has just gone too far. Rather than buy a new set, or worse save up to buy a set of K-Bodies, I decided to try to repair them.
Taking a leaf out of Bessey's book, I thought that inserting grub screws into the heads would do the trick. The serrations on the shafts have a pitch of 1mm as does an M6 thread, so I went and bought a load of M6 x 8mm grub screws.
Take the clamps apart.
The head can be removed from its plastic cover in the direction shown here, though you might need to use a bit of judicious levering to get the walls far enough apart to let the pad pass between them. On my clamps it appears that Besseys break part of the channel that the pads slide into to prevent the pad coming out again - if this has been done to yours you will need to lever the broken part out of the way with a screwdriver. You can just see where I have done this in the photo.
The tapping drill size for M6 threads is 5mm, so chuck up a 5mm drill. To hold the heads on the drill press rig up one of the shafts in a vice on the table and clamp it firmly to the table so that the drill bit just misses it by around 0.5mm. Note that the shaft passes through one of the holes in the table. The shaft is 5mm wide so you can just drop the drill bit into the gap between the jaws to centre it. Note also that the vice is positioned next to the edge of the table to allow clearance for the head's handle when drilling - see below.
Set the depth stop on the drill to produce a 10mm deep hole and drill two holes in each clamp head in the positions shown here.
If the hole is in the right place there should be a paper thin wall left between it and the slot through the head. If there is no wall you won't be able to get the shaft back through the head once the grub screws are installed. If the wall is too thick the grub screws' threads won't engage with the shaft.
The hole in the bottom face can be tapped by hand
but unfortunately the tap handle will clash with the clamp handle for the upper hole, so that is best tapped at the drill press turning the chuck by hand.
The threads should just break through into the shaft slot, so that when a grub screw is inserted it looks like this
This one is about as far into the shaft slot as you'd want it to be, slightly less would be better. Note that the grub screw is bottomed-out in its hole and is firmly screwed into place; it should not come out of its own accord.
Re-assemble the clamps, and continue to use them for a few more years (I hope).
With this mod I guess that they are now Uni-K-Klamps.
Taking a leaf out of Bessey's book, I thought that inserting grub screws into the heads would do the trick. The serrations on the shafts have a pitch of 1mm as does an M6 thread, so I went and bought a load of M6 x 8mm grub screws.
Take the clamps apart.
The head can be removed from its plastic cover in the direction shown here, though you might need to use a bit of judicious levering to get the walls far enough apart to let the pad pass between them. On my clamps it appears that Besseys break part of the channel that the pads slide into to prevent the pad coming out again - if this has been done to yours you will need to lever the broken part out of the way with a screwdriver. You can just see where I have done this in the photo.
The tapping drill size for M6 threads is 5mm, so chuck up a 5mm drill. To hold the heads on the drill press rig up one of the shafts in a vice on the table and clamp it firmly to the table so that the drill bit just misses it by around 0.5mm. Note that the shaft passes through one of the holes in the table. The shaft is 5mm wide so you can just drop the drill bit into the gap between the jaws to centre it. Note also that the vice is positioned next to the edge of the table to allow clearance for the head's handle when drilling - see below.
Set the depth stop on the drill to produce a 10mm deep hole and drill two holes in each clamp head in the positions shown here.
If the hole is in the right place there should be a paper thin wall left between it and the slot through the head. If there is no wall you won't be able to get the shaft back through the head once the grub screws are installed. If the wall is too thick the grub screws' threads won't engage with the shaft.
The hole in the bottom face can be tapped by hand
but unfortunately the tap handle will clash with the clamp handle for the upper hole, so that is best tapped at the drill press turning the chuck by hand.
The threads should just break through into the shaft slot, so that when a grub screw is inserted it looks like this
This one is about as far into the shaft slot as you'd want it to be, slightly less would be better. Note that the grub screw is bottomed-out in its hole and is firmly screwed into place; it should not come out of its own accord.
Re-assemble the clamps, and continue to use them for a few more years (I hope).
With this mod I guess that they are now Uni-K-Klamps.
