Reed Spline for Chair Caning, 6 ft Coil, Sizes #6.5 to #11

Reed spline is the round-topped strip that locks a pressed cane seat into the groove routed around the seat frame. It is natural rattan core, slightly wedge-shaped, so the narrow edge goes down into the groove and the rounded top finishes flush with the wood. Each coil is 6 ft, enough for one average chair seat.

Spline is sold by number, and the number follows the width of the groove:

• #6.5: grooves narrower than 1/8 in (about 3/32 in)
• #7: 1/8 in groove
• #7.5: 5/32 in groove
• #8: 3/16 in groove
• #8.5: 7/32 in groove
• #9: 1/4 in groove
• #9.5: 9/32 in groove
• #10: 5/16 in groove
• #11: grooves wider than 5/16 in (about 3/8 in)

To measure, take out the old spline and clean the groove first. Then slide drill bits into it shank first: the thickest shank that drops in without forcing gives you the width. Calipers work too. Check in a few places, because old grooves wear unevenly.

For length, measure the groove all the way round the seat and add 6 in for trimming.

To install, wedge the soaked cane into the groove and trim it, then soak the spline in warm water for 10 to 15 minutes. Run a bead of wood glue into the groove first, lay the spline over it and tap it down with a mallet over a hardwood wedge until it sits flush. Wipe off squeezed-out glue with a damp cloth, and trim the ends so they meet neatly, usually at the back of the seat.

Measure rather than guess. Old spline carries no size mark, and grooves differ from one maker to the next, so check the clean, empty groove with drill bit shanks or calipers and match the width to the chart. If the width falls between two whole sizes, that is what the half sizes are for.

If you are torn between 1/8, 3/16 and 1/4 in, the sampler set with #7, #8 and #9 lets you test-fit all three. The right spline goes in with firm tapping and sits flush.

For length, if the groove plus 6 in comes to more than 6 ft, as on a bench or settee, order two coils or the 65 ft coil.