New and Improved Mast Crutch Roller

[Tomfoolery]

Being annoyed to no end by the poor fit of the OEM mast crutch roller to the mast, and the difficulty in rolling the mast over it, I decided to play with some alternative crutch roller geometries and materials.

This is a fairly accurate sketch of the original roller with the mast on it. One view shows the naked mast extrusion, and the other is the area where the spreader sockets are. I fudged the sockets, but the formed SS strap they're welded to is accurate. It's obvious that the mast rides in the bottom of the roller, but is provided with no side support, so the mast tends to roll over onto its side. The roller also doesn't roll very easily, though there is a nylon sleeve available from BWY to make it run easier. Won't solve the tilting mast issue, though, of course.



I had some 1/2" thick Starboard left over from my Honda BF50 mount rework, so I cut some circles and made a 3/8" dia. arbor for my wood lathe. I turned the disks to the profile shown in the next sketch. It's an amazing improvement, as the roller turns effortlessly with the weight of the mast on it, and the mast doesn't fall over any more. One problem I didn't foresee (though I should have) is the strap with the spreader sockets - being wider, it hits the roller. I can get around that easily enough by either just running it hard over the roller, or by giving it a little boost to get by.

The mast rides lower in the crutch, which makes the strap that holds the mast in place on the crutch too long. I'll either have to drill another hole in each one, or use a shorter strap. Or make another roller, which is what I'll do, as this was just an experiment, and I didn't put much effort into details.



Here is a shot of the actual roller. Notice that there is a slight air gap between the mast and the roller in the middle of each side. That intermediate roller disk doesn't do anything anyway, other than act as a spacer, so I left a little air space. The mast is supported on the smallest rollers, and kept in place by the sides of the small ones and the top-inside edges of the largest ones. Being that they're separate disks at 1/2" thick, the smallest rollers run at a higher rpm relative to the largest rollers when they're contacting the mast. If they didn't, there would be some resistance to rolling as they fight each other, and the mast would be slipping on one or the other.

The mast is very stable in it, runs through it easily (except for the spreader socket area), and being Starboard, should be quite durable.



A new and improved version follows.

[Tomfoolery]

For my next act, I'm going to remake the rollers with a larger diameter center section, to bring the mast back up to where it was with the original so the strap fits better, and to (possibly) make it roll even easier. Mostly, though, to allow the spreader sockets to clear the large disks on the outside.

It doesn't take much to keep the mast straight in the roller, so I can step the outer disk back a bit to clear the socket weldment without compromising stability. If the mast tries to roll, the largest disks are still there, but I don't forsee a problem there.



Turning Starboard on a lathe is a breeze, and for a change, it's not dusty. Makes a BIG pile of curlies, though, and that stuff likes to get wrapped up in the work, around the tools, everywhere. I just about filled a trash can with what was machined off, though it's mostly air.

If someone wanted to do this, but didn't have access to a wood lathe, another way to do it would be to use 3 different size hole saws to make disks. When finished, just bore the pilot hole out to clear a 3/8" pin. I used a 3/8" drill bit because a 3/8" bit will make a slightly oversized hole anyway, and most bolts and pins are a few thou under also.

You'd still have to jump the mast over the socket weldment, but that's easy. It's almost not worth redoing what I did the first time, but I just can't leave it alone when it can be 'improved'.



The plain round disks shown in the last pic can be made with 1-5/8", 2-1/2", and 4" hole saws. Obviously, since hole saws are made to make holes, the disks you're left with will be smaller, which I've taken into account. It won't be perfect, but then, it doesn't have to be. This isn't a high speed roller, so a little off-center won't hurt anything. If any disk is a little binding, clean the inside edge with a hand file. Or clamp a belt sander to a table and do a little dressing. You could also clamp a drill to a table (or use a drill press), make a short arbor from a 3/8" bolt, and chamfer the edges with sandpaper or a file.

Anything will be better than the OEM roller.

[windypatrick]

Nice human factors thinking with a concise well executed solution.

Well done!

[Tomfoolery]

I'm not quite sure what that means, but it sounds complimentary, so thanks!

[SeaGriff]

Looks good. But looking at the picture if you make the inside of the roller
a larger diameter wont the outside ones be too large for the stock crutch.
I definitely will be making something like this, this winter.

[u12fly]

That dang roller has been so frustrating on my boat - but I've never really thought to do anything about it till now. Thanks for adding to my to-do list. I have an so I don't have the strap of the spreader hanging down, and of course the mast extrusion is a different shape, but the same problem must be solved. One issue I always run into is the upper stay / forstay attachments always fall onto one side or the other and get jamed in the rolls outter guide bracket... This make me have to stop, put down the mast walk to the stern of the boat un-hook whatever snaged and walk back. Sometimes it is two or three times, which really eats into the amount of time it takes to set-up or tear-down.

[Tomfoolery]

Looks good. But looking at the picture if you make the inside of the roller
a larger diameter wont the outside ones be too large for the stock crutch.

Here's an overlay of the one I already made (magenta) with the one I intend to make (green) and the OEM roller (yellow). The original angle between the new one and the one I haven't made yet remains, but the outer two disks on the not-yet-made one are set back to clear the socket weldment. It's shown a little larger at the OD than the first one I made, but I can cut the chamfer further back (same angle, or steeper if needed) to keep clear of the bend in the side straps. I can also cut the OD back altogether if needed. The real work is in the middle and center disks, but the outer are needed to pad it out the last 1/2" on each side, and to make it easier to lower the mast into and more secure once it's in there. At the very least, it's a bigger target if I'm not standing right at the roller when lowering the mast.

Oh, and I draw everything 1:1, so as far as AutoCAD is concerned, it's actual size.



Edit: I see what you're referring to once I compared the photo to the sketch - I drew the inside bend radius of the yoke piece smaller than it actually is, so a slightly larger outer disk would foul with that inside bend radius. Still no problem since I can just make the chamfer conform to the yoke bend, and/or reduce the OD a little. I drew the axle to yoke inside height accurately, but fudged the bend radius. That's what I get for fudging.

[SeaGriff]

Yes I see it will work by angling in the outside of the outside disks.
I've used alot of ideas off this site and this will definitely be another one.
Thanks for the reply.

[Tomfoolery]

For my next act, I'm going to remake the rollers with a larger diameter center section, to bring the mast back up to where it was with the original so the strap fits better, and to (possibly) make it roll even easier. Mostly, though, to allow the spreader sockets to clear the large disks on the outside.

I made another roller, per the sketch above. This time with the smallest diameter the same as the original so the tangs would fit better. The only thing I didn't take into account were the nuts that hold the spreader bracket onto the mast. They stick out from the bracket tangs, and fouled the largest rollers (on the outside). So I cut a groove into each OD to make room for them. They just touch now, but I may put them back on the lathe and just flatten them, as that large OD really isn't needed. Heck, there wasn't anything remotely that large on the original roller, so anything is an improvement.

[Tomfoolery]

A few shots of the parts being made. That Starboard makes a big mess, but no dust.



Smallest (inner) rollers





Cardboard template





What a mess

[robbarnes1965]

Excellent idea!

[Divecoz]

So what exactly was wrong with the black roller in the first post / photo????

[Azzarac]

That is sharp! So, umm... How much are you selling those for? LOL> Nice work!

[seahouse]

Well done. I like it!

It's one of those "why didn't I think of that" ideas. I might "steal" and copy it!

I was wondering if you could do me a favour and mail me some of those stringy chips? They would do nicely to cover my bald spot!

- Brian.

[Freedom77]

That's terrific. Wish I had the lathe and the skills. Ditto on the bald spot. Accept I refer to as a crap detector. By the way a clean workshop is the sign of a sick mind. Fair Winds and Full Sails....