Bench work & joints · National 5
Cramping & gluing up
8 cards · 4 quiz · 0 exam
Practical Woodworking · National 5 · mrkellydt.co.uk
What you're learning in this topic
Learning intention WALT
We are learning about cramping & gluing up, specifically to:
understand
- the purpose of dry cramping
be able to
- choose sash, G, mitre and band cramps
- glue up and check a frame for square
Success criteria WILF
- I can choose sash, G, mitre and band cramps
- I can explain the purpose of dry cramping
- I can glue up and check a frame for square
Types of cramp
| Cramp | Use |
|---|---|
| Sash cramp | Long bar cramp for gluing up frames, carcases and wide boards |
| G-cramp | Small jobs, holding work to the bench, and holding parts together |
| Mitre cramp | Holds mitre joints at 90° while the glue sets |
| Band (web) cramp | A strap that pulls irregular or many-sided shapes together |
Put scrap blocks between the cramp jaws and the work to stop the jaws indenting (denting) the wood.
Dry cramping
A dry cramp is a trial assembly with no glue. It lets you:
- check that every joint fits and closes up
- check the frame is square (measure the diagonals: they should be equal)
- set the cramps to the right size and have everything ready
- fix problems before glue makes them permanent.
Gluing up
- Dry cramp and check.
- Apply glue (PVA) to both joint surfaces.
- Assemble and cramp, with scrap blocks under the jaws.
- Check for square: compare the diagonals and adjust the cramps if they differ.
- Wipe off excess glue with a damp cloth before it sets: dried glue stops stain and varnish taking.
- Leave to set. Check the cramps aren't bending the frame (winding).
Key terms
| Sash cramp | Long bar cramp for frames and carcases |
|---|---|
| G-cramp | Small cramp for holding work to the bench or small parts together |
| Mitre cramp | Holds mitre joints at 90° |
| Band cramp | A strap for irregular or many-sided shapes |
| Dry cramping | A trial assembly without glue to check fit and squareness |
| Checking a frame is square | Measure both diagonals: they should be equal |
| Stopping cramps denting the wood | Scrap blocks between the jaws and the work |
| Why wipe off excess glue | Dried glue stops stain and varnish soaking in |
Quick check
1. What is the purpose of dry cramping?
- To help the glue set and dry faster
- To check the fit and squareness before gluing
- To stain the wood evenly before assembly
- To clean dust out of the joints before gluing
Show answer
B: To check the fit and squareness before gluing. It's a rehearsal without glue.
2. How do you check a frame is square after cramping?
- Look at it
- Use a marking gauge
- Measure both diagonals
- Measure the width only
Show answer
C: Measure both diagonals. Equal diagonals mean the frame is square.
3. Which cramp would you use to glue a picture frame's mitres?
- A pair of long sash cramps
- The bench vice and a softwood block
- Two G-cramps, one at each corner
- Mitre or band cramp
Show answer
D: Mitre or band cramp. Mitre and band cramps suit mitred frames.
4. How do you stop a G-cramp marking the wood?
- Use scrap blocks under the jaws
- Tighten the cramp as much as possible
- Use more glue so the cramp slides
- Wet the wood so it doesn't dent
Show answer
A: Use scrap blocks under the jaws. Scrap blocks spread the pressure.
Printable worksheet
An I do, we do, you do worksheet for this topic, with a separate answer sheet.