Siegmund System 28 Prisms & Supports
Siegmund System 28 prisms give round, square and rectangular pipes a stable support on a 28 mm welding table. The collar prisms fasten in the 28 mm bores with an M16 countersunk bolt, and the Duo Prism and Prism for Screw Clamps also work on System 28 screw clamps. This collection also holds the supports, spacers, multi clamp tower parts, clamping pipe and clamp stops that Siegmund files under System 28 Prisms & Supports. BTH Sales is the exclusive Canadian importer of Siegmund; orders ship from St. Marys, Ontario.
Compare System 28 prisms
| Product | Prism type | Ø size | Angle | Pipes (per Siegmund) | Item numbers |
|---|---|---|---|---|---|
| Duo Prism Ø 40 | Duo prism for bores or screw clamps (.PA: clamps only) | 40 mm (1.57 in) | 120° | Round pipes; levelled corners also take flat parts | 280650, 280650.A, 280650.PA |
| Vario Prism Ø 50 90° / 120° | Vario prism with screwed-in collar | 50 mm (1.97 in) | 90° / 120° | Round and 45° twisted square pipes up to Ø 50 mm | 280645.1, 280645.1.A, 280645.1.PA |
| Prism Ø 50 135° | Prism with screwed-in collar | 50 mm (1.97 in) | 135° | Pipes up to Ø 80 mm | 280648.1.N, 280648.1.A, 280648.1.PA |
| Prism Ø 80 90° | Prism with screwed-in collar | 80 mm (3.15 in) | 90° | Pipes up to Ø 100 mm and all rectangular pipes | 280647.1, 280647.1.A, 280647.1.PA |
| Prism Ø 120 157° | Prism with screwed-in collar | 120 mm (4.72 in) | 157° | Large round pipes up to Ø 400 mm | 280652.1, 280652.1.A, 280652.1.PA |
| Prism for Screw Clamps | Prism for the screw clamp ball head (.PA: clamps only) | 40 mm (1.57 in) | Not listed by Siegmund | Round and square pipes | 280657.1.N, 280658.E, 280659.PA |
Supports and prism accessories
Siegmund pairs the prisms with supports and spacers to set the working height and distance precisely. Prism extensions screw into every prism, and the collar screw and countersunk bolt hold collar prisms in the bores.
- Set of Supports (280821, with tower 280821.1 and washer set 280821.2): 11 pieces to compensate height differences of 1–100 mm, in steps as small as 1 mm.
- Screw Support Ø 80 (280822): For fine height adjustment from 75 to 110 mm; Siegmund says prism extensions and the set of supports extend the range.
- Spacers Ø 50 / 75 / 100 (280175 to 280177.1): Set any distance quickly by rotation, used with the thread bushing for M16 threads and a square or stop.
- Thread Bushing for M16 thread (280825): The bushing for the spacers.
- Prism Extension 25 to 150 (280649 to 280649.3): Screws into all System 28 prisms to change their working height.
- Prism Collar Screw with countersunk bolt (280669.N): Fastens collar prisms in the bores.
- Clamping Cone (280670): For clamping round and square pipes.
- Countersunk Bolt M16 (009410): Fixes collar prisms in the bores; also sold as a spare part.
Frequently Asked Questions
How are the System 28 collar prisms fixed to the table?
Siegmund says the prisms with screwed-in collar fasten in the 28 mm bores and are secured with the M16 countersunk bolt, item 009410. For free positioning off the hole grid, the collar unscrews from the prism.
Which prism suits which pipe size?
Siegmund lists the Vario Prism Ø 50 90° / 120° for round and 45° twisted square pipes up to Ø 50 mm, the Prism Ø 50 135° for pipes up to Ø 80 mm, the Prism Ø 80 90° for pipes up to Ø 100 mm and all rectangular pipes, and the Prism Ø 120 157° for large pipes up to Ø 400 mm.
Can I raise the working height of a prism?
Yes. Siegmund says the collar prisms have an M16 thread for prism extensions, item 280649, and the extension can be combined with the set of supports or the screw support.
Which prisms work with System 28 screw clamps?
The Duo Prism Ø 40 works in all System 28 bores and on System 28 screw clamps (spindle with 16 mm ball), except the polyamide 280650.PA, which Siegmund lists for clamps only. The Prism for Screw Clamps sits on the ball head of the threaded arbor, so it moves to sit precisely on round or square pipes.
What are the polyamide and stainless steel versions for?
Siegmund says polyamide prisms are used for scratch-prone surfaces, and the stainless steel Prism for Screw Clamps 280658.E is used for scratch-resistant precious metals (rust prevention).
