PDA

View Full Version : Wooden block design



Konrad
11-07-2000, 08:19 PM
I would like to make some wooden blocks for some low-load applications on my gaff rigged sloop this winter. Does anyone know where I can find a design for them? This isn't for the mainsheet blocks, those stay Harken. Any help is greatly appreciated.

Konrad

holzbt
11-07-2000, 08:36 PM
Try Hervey Garrett Smith's "The Marlinspike Sailor", it has a chapter on making rope stropped blocks.

McMichael
11-07-2000, 09:16 PM
One of my favorites holzbt, in addition to
Mr. Smith's other,THE ARTS OF THE SAILOR,both
of which are worn from years of "winter sailing". Two of my favorite projects, and most useful?? Swig blocks and tail blocks.
I truly believe marlinespike seamanship is
one of the most enjoyable aspects in all of
sailing/boating. Both books are still in print. Enjoy!!

Todd Bradshaw
11-07-2000, 09:45 PM
Here are a couple drawings that were lying around in the computer from the stuff in my book. They have been translated from the native drawing program into eps files and then into jpeg's, which doesn't do much for the drawing quality or text management, but they might be of help. I'm sure our fellow forumites will have plenty of other ideas and Norm could give you some tips. The blocks he built for Prairie Islander look great. You can also buy ball-bearing sheaves from Harken and build your own shells if you want to cheat a bit.



http://albums.photopoint.com/j/View?u=1302883&a=9830549&p=32622805 http://albums.photopoint.com/j/View?u=1302883&a=9830549&p=32622802

[This message has been edited by Todd Bradshaw (edited 11-07-2000).]

Syd MacDonald
11-07-2000, 10:34 PM
Use UHMW plastic for your shives. Epoxy it to a wood face plate and turn them on your wood lathe. Use plated copper water supply tubing from under your bathroom sink for your pins in smaller blocks.

dngoodchild
11-08-2000, 07:15 AM
There's an article on building plywood blocks on my Shop and Building Tips page. At the bottom I promised a new edition with rope-stropped blocks "in a few days". That was a year ago. I hope to get to it this winter. The article is at:
http://catalog.com/bobpone/plywoodblocks.htm

Kermit
11-08-2000, 08:23 AM
Nice pictures. Mine are "dime blocks" using those nice Canadian 6-cent dimes with the image of the schooner Bluenose II. For pins I use stainless "all thread." I've tried brass, but it's too soft. Drill for the pins, then chuck the threaded rod in your drill and drive it in, buck off the extra that sticks out, and file or grind them flush. Stainless or bronze for axles, delrin sheaves, ash or locust cheeks.

[This message has been edited by Kermit (edited 11-08-2000).]

NormMessinger
11-08-2000, 09:16 AM
Here is a series of photographs I took as I was making the blocks for Prairie Islander.
http://photomail.photoworks.com/sharing/roll.asp?Key=8337109096280300

I used Schaeffer sheaves from West Marine Catalogue, and added bronze oillite bearings. Schaeffer also makes the same size sheave with ball bearings that is really smooth but $12 in stead of $4. For a smaller block check out Harken "Big Block" sheaves. Nice with ball bearings and not that expensive.

--Norm

Mike Field
11-08-2000, 09:30 AM
The simplest blocks to make are rope-stropped one-piece mortised ones. For low-load applicatons a solid pin and plain bearings will be satisfactory. If you're happy with the look of plastic sheaves, you can buy them very cheaply (but the only ones I've seen are white, which looks terrible.) David's plan for making plywood sheaves is good, but I've made them in a lathe quite satisfactorily.

Don't forget to insert the pin below the half-way point, to leave a good deep swallow for the line to pass through. If you make the pin a driving fit, you won't need to use cover-plates, as the strop will cover the ends securely enough.

The strop should be a grommet, not a short-spliced length of line (see H G Smith.) Strop to a bronze thimble (which should also be purchaseable,) or make your own thimbles from a short length of copper pipe, flared at each end. Renew the seizing after the grommet stretches (a few weeks sailing,) and yearly thereafter.
http://albums.photopoint.com/j/View?u=1231924&a=9091792&p=32647586&Sequence=0&res=high

(Sorry, Norm, I'd written this before you posted your photos. I guess white plastic sheaves aren't all THAT bad!)

[This message has been edited by Mike Field (edited 11-08-2000).]

NormMessinger
11-08-2000, 09:53 AM
White plastic sheaves are butt ugly. [b]BUTT UGLY![/] I say. On the other hand I was in a cheap mode when I did them, the ash covers the sides and the line will cover most of the rest.

--Norm



[This message has been edited by NormMessinger (edited 11-08-2000).]

Todd Bradshaw
11-08-2000, 12:04 PM
You can also steal the brass sheaves out of those cheap metal pulleys that you find in most hardware stores for building small blocks.

Steve McMahon
11-08-2000, 07:14 PM
Kermit - Those Canadian dimes are now ony 4.8 cents U$. But the picture of the Bluenose is still priceless.

TomRobb
11-09-2000, 11:09 AM
I hope the our Canadian friends don't mind using that coin thus. But, Bluenose? What could be more perfect? How large is a Loonie? In diameter?

[This message has been edited by TomRobb (edited 11-09-2000).]

Paul
11-09-2000, 12:00 PM
Hey Norm, nice job on the blocks. This has given me the inspiration to make them for my Haven. Question. On photo 0107613, it looks like you are routing the groove for the rope on your router table. It looks tricky. Any advise on how to do that. I would think that if you went too far the router would catch in the sheeve opening and grab the block and kick it out. How can one go about getting those Canadian dimes?

NormMessinger
11-09-2000, 12:34 PM
Paul. The router bit is a 3/4" round nose set just high enough so that if I had pushed beyond the spacer pieces it would just barely touched the sides, both equally. The cut was so light that kick out didn't seem to be a risk. Clamp on a second fence if it worrys you and a stop block on the fence if you fear going to far. I did each end seperatly rather than push the block through in one pass.

I usually make a couple of extras when I'm working with the router and when with the turning lathe I never know what a project will look like until it comes off the lathe. "Oh well, let's make something else" is my middle name.

--Norm

Steve McMahon
11-09-2000, 12:48 PM
TomRobb: I don't think anyone would mind you using Canadian money for a good cause - it's not worth much for anything else http://media4.hypernet.com/~dick/ubb/smile.gif A "Loonie is about 1 1/16" diameter, or heck - use a Twoonie (I'm not kidding), its 1 1/8" diameter and has a picture of a polar bear.
Paul: if you want some dimes e-mail me with your address and I'll mail you all you want - do you have a preferance of year? By the way - I just finished restoring a 1964 Bluewater Marine 15' plycraft - I used 1964 pennies for all exposed washers. You can polish old pennies by putting them in a plastic jar with some water and sand and shaking it, or if you have a lathe just chuck the jar off centre and spin them for a few minutes.

Paul
11-09-2000, 12:51 PM
Thanks Norm! I had forgotten about the stop block option. I just remembered that when we moved to my wife's family farm in 1988, I did some clean up work and put some very old black locust posts away in an old out building. I think I going to to get some of that out to make the running blocks and wood cleats for my boat. Thanks for sharing.

Paul
11-09-2000, 12:55 PM
Thanks for the offer Steve. I will definately contact you! What a great idea to use the coin dates to add interest. I can see doing something like that for both of my daughters birthdays, etc. They will get a kick out of that and make it all that much special.. Thanks so much!

Dave R
11-09-2000, 01:19 PM
Steve, how much do washers cost in your neck of the woods. I'll bet that it was cheaper to use the pennies.

Steve McMahon
11-09-2000, 01:49 PM
Yup - I expect that copper or bronze washers the same size would have costed about 5 cents each. Of course it was a little bit of work to centre punch the queen in the ear and drill them.

Kermit
11-09-2000, 02:56 PM
Wow! The Canadian dollar is down that much? No wonder my Canadian cousin hasn't been seen this side of the line lately. She keeps telling me to bring my pension and Social Security north when I retire (four-plus years and counting).

Are Canadian pennies still copper? Copper pennies make good roves if you're riveting a boat. I saw a lapstrake boat that had the laps clench nailed between frames and riveted at the frames with the outline of Lincoln's head in the center.

Would someone like to start another thread--or suggest a website--giving some advice on how to make strop ("bullet") blocks? I've made bronze strap blocks, but just haven't tried rope strop blocks yet. Part of what's stalled me is getting the grommet right. I've tried following the various books' directions and illustrations, and it never works out for me. Dave Griswold does a workshop in Port Townsend during the week before the festival teaching block/handybilly making, but it's always the first week of school! Dang!

[This message has been edited by Kermit (edited 11-09-2000).]

Steve McMahon
11-09-2000, 03:15 PM
Today the US dollar is abour 1.542 Canadian.
Not an all together bad thing - exports to the States are good. Canadian Pennies are now made of something other than pure copper - but they didn't change till sometime in the early eighty's. When I need copper I raid my wife's piggy bank for the old ones. I try to use the year that corresponds to what I'm working on.

Todd Bradshaw
11-09-2000, 03:42 PM
Kermit,

Grommets are both a matter of practice and finding the right material. The easiest line for learning is probably something like 3-strand Manila in the 3/8" range from a hardware store. It isn't great line, (kind of coarse for my taste) but it's stiff and holds it's shape. For small grommets, the tarred stuff that West Marine and others sell as "tarred marline" works, though as marline, it leaves a lot to be desired.

Most 3-strand polyester is kind of soft and I found it more difficult to work with. I use a lot of New England Ropes Filament 3-strand polyester, both for grommets and for roping sails. I dunk it in wood stain (Minwax "Early American" oil stain seems to give it the best color) and then rinse it in naptha to get it to mimic natural cordage. The process also stiffens it a bit, making it easier to use for grommets.

It takes a strand about ten times the desired grommet's diameter to do the job (4" grommet = 40" of a single strand, 3 grommets per 40" chunk of rope.) Starting with something stiff makes the lay more aparent as you work your way around and get a feel for the process.

[This message has been edited by Todd Bradshaw (edited 11-09-2000).]

dngoodchild
11-10-2000, 06:11 AM
As you could see from the pictures at my site I used old pre-decimal English pennies for my blocks. You can get them for next to nothing at any coin dealer. They usually have a bunch in the miscellaneous tray where they throw the coinage which is of little value. If you buff them up and varnish over them they really look bright and fancy.

Mike Field
11-10-2000, 07:23 AM
Kermit, further to Todd's post on grommets, I think a bit of used hemp or other natural fibre would be good for practising with. The reason is that the outside will be discoloured, so when you unlay your three strands (which do carefully, so as to disturb them as little as possible,) you'll be able to distinguish clearly between inside and outside. And the reason for this is that when you come to lay up your strand you need to give it a slight twist (to the left for right-handed line) so that it lies snugly in its groove, and the colour will tell you if you got it right. (Without the twist, the whole thing becomes baggy and unshapen.)

Make the grommet of a size to be a snug fit around block and thimble placed so as they touch each other. Then when you put the seizing on, the strop really tightens up around the block.

Once you've wound the strand three times, finish (as all the books say) "as for a long splice," which means, tie the first half of a reef knot left over right, then tuck each end once against the lay, flattening and spreading the yarns out a bit as you do so. (You can add a tapered tuck or two if you want, but it's really just gilding the lily.)

When you've finished, roll each part of the grommet between your hands or under foot, just like you do for a splice, to help the strands to settle properly in place.

And when you strop, place the grommet so the join is centred under the arse of the block.

By the way, if the grommet takes on a stubborn figure-of-eight twist to it as you're laying it up, there's no way it can be cured. You have to unlay it and start again, changing the amount of twist you give the strand at each crossing (another reason for practising with discoloured rope.)

I reckon rope-stropped blocks are great. They look the part (see my photo link above,) they're the least expensive to buy, they're the easiest to make, and they have a built-in shock absorber. What more could you ask for?

Ian Wright
11-10-2000, 01:42 PM
Don't use English pennies,to big, use ha'pennies, one inch in diameter and a nice Tudor ship on the reverse. Also no need to drill, put the holding screws at the edge of the coin and let the over lapping screwhead hold 'em in. Or glue 'em in, but NOT with epoxy.

IanW

Dave Hadfield
11-11-2000, 10:48 AM
I've made quite a few rope stropped blocks now for my 40ft ketch. I made them very simply and they work well. I used both mortised shells, shells laminated with epoxy and shells laminated with a polyurethane glue. The poly glued shells failed -- came apart at the glue line. I don't know why, but expect it had something to do with the required moisture content in the wood for the glue to bond. Even so, the failure was not a problem because the grommet held it all together anyway -- kind of like belts and suspenders. I like the mortised, single-piece shells best, because you can just dunk them in very hot oil, and there they are, preserved for the next season. I wouldn't do that to epoxy.
The grommets are not hard to make. Use the Marlinspike book directions -- I did, and got great satisfaction from learning the skill. I used manilla, which when soaked once a year in boat sauce, works fine. Since then though, I've aquired English Braid Buff Polyester rope, and I expect I'll use that. I serve the grommet around the thimble with tarred nylon.
My sheaves are all turned from Jotoba, odd bits of which I had left over from flooring my living room. This is a tremendously hard wood which turns like aluminum and doesn't like to split. You have to drill little indents to get the lathe chuck teeth to grip. I wouldn't hesitate to use locust or ironwood.
Round thimbles are very hard to find. I made my own out of 3/4" copper pipe joiner sleeves, using DGC's method of 2 ballpeen hammers and a torch. Again, it's a source of pride to have made them, they cost peanuts and they work just fine.
There is no bronze rod in Barrie Ontario, so I used brass 1/4" and it works fine -- even on the 4 part tackle I use to go up the mast and for my mainsheet blocks, there is not too much load for the brass.
The whole completed block is a good system. Soaking it in hot boat sauce rejuvenates the shell, the sheave, the manilla and lubricates the pin.
I'd use bearings and bronze sheaves if I could easily get them, but to be honest what I've made is completely functional for the loads they bear.
The manilla should be inspected from time to time, but with a little care it lasts longer than you think.
For boat sauce I start with zinc napthanate rope preservative, add pine tar and tung or danish oil to "taste".
I know that all sounds archaic, but it means you can have a whole box of blocks on board, singles and doubles, with beckets and without, and always come up with what you need. If you buy blocks from Haarken, the price scares you away from buying anything extra, and you end up with never quite enough blocks on board to make that extra little modification you'd like to try.
I do have some modern blocks and I use them for halyards at the mast heads, for obvious reasons.
These are fun things to make. I recommend it. Good luck.

Dave Hadfield
11-11-2000, 10:49 AM
I've made quite a few rope stropped blocks now for my 40ft ketch. I made them very simply and they work well. I used both mortised shells, shells laminated with epoxy and shells laminated with a polyurethane glue. The poly glued shells failed -- came apart at the glue line. I don't know why, but expect it had something to do with the required moisture content in the wood for the glue to bond. Even so, the failure was not a problem because the grommet held it all together anyway -- kind of like belts and suspenders. I like the mortised, single-piece shells best, because you can just dunk them in very hot oil, and there they are, preserved for the next season. I wouldn't do that to epoxy.
The grommets are not hard to make. Use the Marlinspike book directions -- I did, and got great satisfaction from learning the skill. I used manilla, which when soaked once a year in boat sauce, works fine. Since then though, I've aquired English Braid Buff Polyester rope, and I expect I'll use that. I serve the grommet around the thimble with tarred nylon.
My sheaves are all turned from Jotoba, odd bits of which I had left over from flooring my living room. This is a tremendously hard wood which turns like aluminum and doesn't like to split. You have to drill little indents to get the lathe chuck teeth to grip. I wouldn't hesitate to use locust or ironwood.
Round thimbles are very hard to find. I made my own out of 3/4" copper pipe joiner sleeves, using DGC's method of 2 ballpeen hammers and a torch. Again, it's a source of pride to have made them, they cost peanuts and they work just fine.
There is no bronze rod in Barrie Ontario, so I used brass 1/4" and it works fine -- even on the 4 part tackle I use to go up the mast and for my mainsheet blocks, there is not too much load for the brass.
The whole completed block is a good system. Soaking it in hot boat sauce rejuvenates the shell, the sheave, the manilla and lubricates the pin.
I'd use bearings and bronze sheaves if I could easily get them, but to be honest what I've made is completely functional for the loads they bear.
The manilla should be inspected from time to time, but with a little care it lasts longer than you think.
For boat sauce I start with zinc napthanate rope preservative, add pine tar and tung or danish oil to "taste".
I know that all sounds archaic, but it means you can have a whole box of blocks on board, singles and doubles, with beckets and without, and always come up with what you need. If you buy blocks from Haarken, the price scares you away from buying anything extra, and you end up with never quite enough blocks on board to make that extra little modification you'd like to try.
I do have some modern blocks and I use them for halyards at the mast heads, for obvious reasons.
These are fun things to make. I recommend it. Good luck.

Todd Bradshaw
11-11-2000, 01:12 PM
Dave,
Both Bainbridge/Aquabatten and Challenge Sailcloth carry round thimbles and most sailmakers get fabric and supplies from at least one of them. Next time you need them, check with your sailmaker, or get in touch with me and I'll get you some.
T.E.B.

Smacksman
11-12-2000, 06:03 AM
Surely, the beauty of rope stropped blocks is that you splice them straight into the end of the line. No grommets, thimbles, shackles.

Dave Hadfield
11-12-2000, 08:08 AM
Todd, thanks for the tip. When I figured out the method for making my own I carried on and made about 2 dozen, so I'm all set for now. I thought the copper might deform under load, but after one season there's no sign of it and in my fresh-water environment there's no discernable corrosion.
Smacksman, you're right. If you want a block on the end of a line it's best to splice it there. I do indeed have one simple tackle set up that way and I use it for tensioning my mizzen staysail halyard, by tying a rolling hitch onto the halyard and the other end to a lower cleat on the mast. But there are places where I want the block shackled to a hard point, and then I want a thimble and shackle, hence a grommet.
I've got a drawer on board full of blocks and thimbles, and 3-strand rope for grommets, so I can make them up as required. It gives quite a feeling of satisfaction to open that drawer and see them there.

Dave

T.KAMILA
11-14-2000, 06:55 AM
Todd, on the bullet block in your illustration can the body of the block be turned? Geometry looks to be the same front and side view. The section view looks different.

1. Start with a rectangular block little wider in width than thickness.
2. Mortise it out and drill hole for pin.
3. Turn on long axis like a symmetrical egg and leave the flats on the thickness side.
4. Finish with the routed groove and smooth sand.
5. Or just leave the width and thickness the same in the beginning and end up with no flats on the sides.

I am making for 5/16-rope dia.

I like this simple stuff it has grace!

Tom Kamila


[This message has been edited by T.KAMILA (edited 11-14-2000).]

Todd Bradshaw
11-14-2000, 11:45 AM
Probably, though I'm not that good with a lathe. Everything I make looks like a belaying pin or candlestick - which is fine unless you are making something that isn't either a belaying pin or candlestick. I usually rough them out on the bandsaw and attack with whatever hand tools seem to be doing a good job, mixed with some work on the stationary belt sander.
The rope groove needs to be dome-shaped on the sides, so the rope doesn't want to pop out and the shell has to be cut back enough that the sheet or running line doesn't bind as it goes into and out of the block. Other than that, the actual shape is pretty much up to the builder.