Source for stretcher expansion bolts

For quite a while, I have been trying to locate a supplier of
painting stretcher expansion bolts, so far without much success.
Does anyone know who sells *just* the bolts and possibly bulk
amounts of them? It would also be interesting to know whether there
are any permanent tension (spring loaded or otherwise adjustable)
stretcher systems commercially available. If none of them is
commercially available, could someone supply the design in order to
get them custom made (as long as they are not patent protected)? Any
information would be gratefully appreciated.

Stephan Schaefer
ArtCare & Consulting
Rua Oscar Freire 715/81
01426-001 Sao Paulo, SP
Brazil
+55 11 8819282
Fax: +55 11 2809519

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                  Conservation DistList Instance 13:26
                Distributed: Wednesday, October 20, 1999
                       Message Id: cdl-13-26-013
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