wood block construction ?

[c.grillo]

I am a novice here and searched the forum first but found nothing. I will be rerigging a 42 ft schooner and want to make rope stropped blocks. Yes, it's winter and I'm looking for indoor projects, have time and not enough money but want wood anyway. I would be interested in hearing the pros and cons of built up vs solid construction and any tricks to each method...and/or a good book/article on specifics. I will have aprox 30 for 1/2" line (about 1/2 of those doubles), 30 for 3/8 and a half dozen 5/16.

I have access to local elm or ash and several sawmills within spitting distance...any other recomendations for wood?

Anyone have a good source for durlin in 5/8, 1/2, and 3/8?

Rules for axle diameter? (I plan on bushing the sheave)

Rules for sizing the diameter of line for the strop grommet?

I recieved some samples of "spunflex" and like working with it better than dacron. I don't find much written about it except it isn't as strong or chafe resistant. Does anyone have recomendations on sheave size? On the spunflex in general?

I appreceate any direction available.
Conrad

[Brion Toss]

Hello,
You'll find directions for making rope-stropped blocks in the "Apprentice". Also sheave size recommendations. As for the grommet materials, what are the loads? A properly-made grommet should be close to twice the strength of the rope it is made from. How does that compare with the loads on the block?
Is it "Delrin" you are after? I'd go to Zephyworks; they make fine bushed Delrin sheaves.
Fair leads,
Brion Toss

[c.grillo]

Thanks Brion,

"Apprentice" has been helpful. So is your post.

Any thoughts on solid vs built up construction? Seems commercially available rope stropped blocks are made from, solid. For one without milling equiptment it would appear that glueing and pinning the bodies might be easier. Any suggestions from those that have done it?

[allene]

google "stropped blocks" and find a couple of helpful articles addressing your question. For example, this one:
http://www.duckworksmagazine.com/02/...odenblocks.htm

Allen

[c.grillo]

Thanks for the link. I've seen that one. Running the grain as he does in the cheeks worries me for strength. A good bump to the side looks like a split waiting to happen. With the grain the other way it would appear to be much more robust. And, yes, this is just the sort of info I seek...Those ones are for a dinghy of course and not as critical.

[allene]

Looking at the forces it looks like the wood is in compression due to the strop. My first thought is that you want the grain running across the strop like he has it. Also, the pin should probably be relative to the grain the way he has it. Just my 2 cents.