DN NA Class

One of the changes I plan for my boat over the summer is to remove most or all of the rake in my steering post.

To do that, I need to remove the current Aluminum/Oilite bushing tube.  I'm assuming if I heat it up I can remove it, but the nose-block in my boat is solid, so there's a fair bit of glue-surface to soften.

Any suggestions on the best technique(s) to remove it? (without damaging the wood too much ;))

I have industrial heat-guns and a torch available.

Cheers,

Geoff S.

I'd say start with the heat guns to see if you can soften the epoxy and break it free. If that doesn't work go to a fine tip torch on the inside of the tube.

Can I ask why you want to get rid of the angle?? I am a few days away from drilling a new hull and I was planning on some rake for better turning.

I'm not sure the rake helps, and I've had a persistent lee-helm problem with this hull (since I built it).  I'm hoping that the rake may have something to do with it (by causing the rear of the steering chock to touch the top of the runner).

First I'll re-measure the rake to make sure it's not something silly like 1 degree, but I'm pretty sure it's closer to 4 degrees.

Cheers,

Geoff S.

 You could drill a  series of holes around the outside of the tube,
 then angle the bit back and forth to get the space between the holes  .
 this will give you a little larger hole to reglue the tube in.
 The little larger hole will hold the tube in stronger.

 It worked for me once , I used a 1/16 bit

 George Reis  DN 5053

Geoff,

Lee helm. 

In my experience, the lee helm was caused by the steering chock restricting runner pivot movement, forcing the runner to contact the ice in back of the pivot bolt.  In my case, this was in using a very old chock, and too much runner rake, which caused the top of the runner to hit the  back of the chock, tipping the runner up and making it ride on its tail (actually, on the edge near the tail).  It only happened when the boat was held tight to the ice by the mast loads.  I also saw it on a boat that the builder decided to mount a new Sarns chock backwards, with the steering bar on the left.  I solved my problem with some gentle cutting and grinding at the back of the chock.  The contact was in the rolled-over steel of the chock and the top corner of an insert.  Plates did not cause the problem at all.

Rake and no-rake seem to work nearly equally well.  Straight is easier to measure in your boat, as some dimensions are based on the runner pivot bolt. 

I carry about 5 degrees of rake, because the theory of the outside edge digging in while turning seems so compelling.

Bearing Removal

If you are set on removing the bearing, heat gun and a hammer, using the proper sized socket from a socket wrench set to line up with the bearing housing as a tapping device..   Add extensions as required until it falls to the floor.  (Use one with an unlimited replacement warranty!    ;) )

Alternatively: A long 1/2 inch bolt and a spacer block on the bottom is an alternative, using pure force rather than impact is an alternative.  Drill the block to over 1 inch so the housing will go into the hole, insert the long bolt through the bearing and the block, and tighten a nut to pull the housing out through the bottom.  A few properly sized washers are required, you can figure out where.

You will then have to either fill the hole and re drill, or hog teh hole to vertical. 



Ken

It sounds like some heat, the proper sized socket with an extension, and a hammer drill would do the trick. If you have an air chisel to push the socket, that would be even more intensive. I'm sure that once you break it loose, it will just keep moving.

Now you guys have me thinking....keep it simple and plumb, or 4-5 degree rake?  I'm feeling some accomplishment tonight, I just finished the last of the gluing on my hull. Now it's on to installing the bushings and the final sanding for the finish coat of epoxy and varnish.

I've removed a couple steering tubes, and I settled on using a torch.  If you try a heat gun I would think it could take alot of patience, or liquor, or both.  The one thing I did learn, cut a hole in a peice of 1/8" plywood and put it over the top of the tube to protect the deck (or bottom) from charring - or don't if you want to add some "patina" to the front of your hull.

Looking at the posting date, I imagine Geoff has already worked this out - how did you do it Geoff???

As far as rake, I like to use around 4 degress, and feel it gives me better steering.  The best steering boat I've ever built had 7 degrees of rake, however I had to modify the front runner to fit the chock without interfering.  4 degrees is about the limit using the Sarn's "low-profile" chock befor runing into interference problems.

I'm pretty impatient, but I don't see a problem there...  ;D


I like the notion of using the plywood as a shield.  I've done that on a smaller scale when we've used screws to hold the skins on a Renegade down to the bulkheads during gluing.  In that case, I found the holes in a steel framing bracket were just right to allow the micro-torch flame to heat the screw head, but not burn the wood (too much...).


Quoting Bugs Bunny, "You don't know me very well"...

I can procrastinate better than anybody!  We've been working on a number of projects at The Boatwerks (http://www.iceboat.org/photos/nordhaus/nordhausboatworks.html) recently (including a really cool project where we're cutting up a partially rotted Renegade springboard and putting it back together...) so I haven't been looking at my DN much. 

I have removed the steering chock I borrowed after the GC/NAs and very carefully measured the rake on the steering post.  It's about 2 degrees, leading me to believe that it's not the source of my lee-helm problem.  I don't see any evidence on the chock and runner contacting (where I cut away part of the stiffener to give more clearance).

Based on those measurements, the general comments about rake, and my plan to install a short European-style steering chock (that shouldn't have any interference problems, even for extreme rake), I think I'll leave it alone.

I've started another thread (http://dnamerica.org/forum/index.php?topic=616.0) for discussion/suggestions about the underlying "lee helm" problem.

Cheers,

Geoff S.

How about taking a hack saw blade and inserting it into the tube, Install the hack saw to the blade and carefully cut the tube in a couple or more locations length wise to releave any structual integerty. This always worked with suspenion bushings.

Steve

Cutting the bushing/tube with a hacksaw would work for removing the tube, although it still might take some heat to break the epoxy bond.  It would also be pretty hard to cut through the full length of the tube without getting into the wood, although some small cuts into the surrounding wood shouldn't hurt.

This would also destroy the tube, whereas the other methods mentioned would preserve the tube, allowingit to be reinstalled at a new angle.