bending frames without steam

[neptoon]

I just read an article in wooden boat about bending small frames..herreshoff would slice the hard turn of a frame the curf of a saw blade.almost replicating the ease of bending laminates...he also mentioned of a small amount of damage done to the strength of wood by steam...this curf cut was done near the hard turn of a frame aproaching the bilge...and the length of the cut was the length of the acute radius.....please give me any type of input

[Jay Greer]

Although I am not aware of Herreshoff doing any cold bending of frames, kerfing does make a hard bend easier. since the out side of the curve is stretching the wood and the inner surface is in compression, it makes a lot of sense to kerf the frame in the area of the hard bend. Mind you, the kerf begins at one end of the frame so as to allow the split material to slide over each other with the bend. This type of framing is best done in conjunction with rivet fastening as a screw will not draw up the kerf unless the shank is entirely in the molded section that fays to the planking. And, this will bring the threaded section of the fastening too close to the inboard surface of the frame, possibly splitting it.
JG

[ 11-24-2005, 07:16 PM: Message edited by: Jay Greer ]

[neptoon]

there is also the problem of attaching it the the floor timber...look at wbm #186...october and see what you think....thanks for the input

[Jay Greer]

In this case, floors would land directly on the frames.
However, this creates a hard spot at the top of the floor that can cause frames to fracture. A more elegent solution is to build cast bronze floors with a tapered strap that lays over the inner surface of the frames. Planking is then through bolted or riveted through the frames and floor straps. Frames then do not need to extend into a keel pocket or take a hard bend to the bearding line as the flange edge of the floor will provide a connecting surface for the frames and planking as well.
JG

[ 11-26-2005, 10:43 AM: Message edited by: Jay Greer ]