Sash clamps are used to glue up wide panels and large assemblies, not just for doors and the like but for many more assembly tasks that the name would suggest. If you are making table-tops, assembling casework, making glue-lam boards or laminated beams, these clamps are just the thing for exact and secure glue jobs. The clamps consist of a sturdy beam, a clamping head, and a head that can be moved along the bar and fixed solidly in place with a lever.
A combination of light weight and high strength was the design brief for these clamps, making them especially suitable for many of our clients who have relatively small shops and must tuck them away somewhere after every job.
The bars on the JUMMA Sash clamps are made of 3.5 mm thick high-strength aluminum, of an alloy often used in the aircraft industry. The clamping heads are also made in a tough, shock resistant aluminum alloy. In contrast to many clamps with steel beams, and steel or cast iron heads, these make for much lighter weight, which is useful for storage and also just while handling them in glueing up casework. The screw on the fixed head has a throw of 36 mm, a diameter of 12.7 mm with a contact spacing of 25.4 mm. The “tommy bar” to turn the screw is 94 mm long. The moveable clamping head can be easily fixed and released with a small lever that fits into a slot in the top of the bar. The heads are covered with rubber pads so you don’t need to fiddle with scraps of wood to protect the workpiece. The heads are also angled slightly in, to avoid bowing up a workpiece as it is clamped. The clamping heads allow a clamping height of 48 mm, and are 57 mm wide. Screws, bolts and screws are made of steel. Clamping force: up to 3,400 newtons.
height x width
||35 x 21.5 mm
||48 x 57 mm
||35 x 21.5 mm
||48 x 57 mm
In the photo below, you see 4 of the sash clamps with the 600 mm clamping width in action. Be careful when ordering to get enough of the clamps to do the jobs you need to do. If the clamps are too widely spaced when glueing up long boards, for instance, it can be that not enough force will be applied between the clamps. We recommend a distance of 30 cm between clamps, though of course a little more or a little less is fine, depending on the job at hand and if one has to bend warped boards.
With wide glue-ups, it is smart to guard against the workpiece bowing or cupping by using scraps and two extra clamps to keep the assembly flat (Sorry, picture shows only one clamp). Because the faces of the clamping heads are angled slightly in, this helps to prevent bowing the workpiece, but if you have three or more boards, this feature no longer works very well.