Don Weisman writes:
Rocking chairs with broken back spindle Tenon's at the Crest rail are
nothing new and a common shop repair. Some people foolishly try in
vain to glue them back, while others try to insert a short dowel rod or
dowel pin which only serves to further weaken the spindle, causing a
more major damage somewhere down the road. Some even try to
insert a small diameter dowel pin, never giving thought to that if a
thick tenon snapped, how could a 1/4" dowel pin hold?
This is a method we use, which improves much upon the original
installation. I'll explain as we walk through it step by step.
Let's assume there that one of the main end spindles tennis
and one back spindle tennis broke at the crest rail.
1. Remove the Crest rail by sawing off the remaining end main spindle.
2. Remove any broken tennis from the crest rail and discard.
3. Remove the Crest rail using a small dead blow hammer (12-15 oz)
4. Measure the length of each crest rail hole to verify that each one
has a minimum of 3/4" length. If not, drill to that length.
5. Measure down 3/4" on the two end posts and mark a line.
6. Make an appropriate size tenon using a Tenoning bit or Dowel making
bit, and chamfer the top edge of the tenon with a dowel end former.
7. Set the Crest rail on the two ends and dry fit.
8. Remove each back spindle one at a time, clean out old glue and dry
fit. Replace in original position.
9. Mark a line for depth and create new tenon up to that line.
10. Cut off the excess beyond 3/4". This can be done at any convenient
time while the spindle is out of the seat.
11. Note that back spindles should be marked taking into consideration
that when pulled forward will be in a longer position by about 1/8".
In other words, if back spindle is leaning in back of the crest rail,
pulling it forward into position and to line up into the hole will make
the spindle "grow" slightly. This is important so that the tenon
shoulder will not be too noticeable.
12. After dry fitting completely, remove, add glue to top and bottom and
drive home. Also note that it's sometimes easier to glue the seat tennis
separately, first.
What has been done here is to shorten the entire back height by 3/4",
and that will not be noticeable. Also, all the tennis are new, fresh and
the tennis are fitting deeper than the original, adding much strength.
In addition, all the spindles have been reglued. Little or no touch up
is required. We use this method quite often and it saves a lot of time
as opposed to repairing...plus it's better and saves the customer money
in repairs.
Not shown is a new back spindle and one new blade (rug cutter) rocker,
both in hard Maple.
Don Weisman
Abacus TX
swivel-chair-parts.com
