Opinions wanted on my fender design

[repete]

[Mitheral]

First, how the heck do I make that two step hole with a standard drill? Just use one bit to make the small one, then go with a bigger bit but shallow? Or do I HAVE to buy a forstener bit?

Drill the larger hole first. The hole left by the point of the larger bit will align the smaller bit. I used forstner bits but a plain old spade bit is sufficient.

You don't really need to drill the smaller hole though for mounting fenders. I used the two step hole to increase accuracy of the insert because the bolt threaded into it was supporting a cam that operates the lifting mechanism for the mobile base of my saw. If the insert securing a fender is a few degrees off of 90 no one is going to notice.

Also, how do I accurately align the holes in the fender with the holes in the frame? In other words, if the fender is already fully assembled, it's not like I can fit my drill in there to drill it at a straight angle through both the fender and frame at the same time to at least align the holes accurately.

Drill the the holes in your fender. Clamp the fender against the teardrop side (use 200mph tape if you have to or get someone to hold it). Use a pencil to mark the location of the fender holes. Drill the teardrop for the inserts. Insert inserts then mount fender. If you drill the fender holes a bit over size you don't need to get everything perfect. It is why they invented fender washers.

Also you are going to want to seal the end grain exposed by drilling the holes in the teardrop. After drilling slather in some diluted wood glue or varnish. I'd use a stainless bolt and washer.

When fenders on cars used to be bolted on a fender welt was used to hide gaps and stop the fender from rubbing the body. You can still buy it but I'd just use a strip of foam tape.

[Mitheral]

Oh one other thing. You can practice inserting the insert. Just drill a few holes in a chunk of 2X4 and insert away. You won't be able to use the bolt method to remove the insert but a quarter turned with a crescent wrench works.

[Ira]

Thanks, guys.

And no, they sure ain't all assembled yet. But I'm going to want to assemble them before mounting, because it's a matter of timing. (Being able to get to the boatyard to confirm the tire clearance measurement first, working from home to complete them, blah blah, blah blah, also staining and epoxy before mounting.)

Sounds like drilling from the back end, then sticking a pencil from there into frame to mark the frame makes the most sense for me.

Dale, did you find our inserts yet?

HAH!!!

[cracker39]

Ira, you asked that favor AFTER I went to HD this morning, or I would have checked on them.

[Ira]

Ira, you asked that favor AFTER I went to HD this morning, or I would have checked on them.

Can't you go back right now?

[goldcoop]

Ira, et all:

Softwood does not hold insert nuts very well.

These nuts are fairly short and don't have alot of purchase in the wood.

If you really tighten up these fender mounting bolts they may just POP out the insert.

I just hate to see you guys looking in the rear view at your fenders bouncing down the road, or worse, thru someones windshield!

You may want to consider HANGER BOLTS!

http://www.leevalley.com/hardware/page. ... 3715,43727

Yes they can be bought at HD or Lowe's the are in the hardware aisle, in blister packs.

Go for something 3/8" x 2"? They are measured OAL, 1/2 wood threads, 1/2 machine threads.

Just drill a 5/16" hole for 3/8" hanger bolts, double nut the machine threads and screw 'em in 1" or so for SECURE fastening.

3 of 'em/fender should do the job. I guess in this case you could drill three 1/2 holes in your fender, place the fender at proper loc, mark side of TD, remove fender, drill & drive the hanger bolts.

Cheers,

Coop

[cracker39]

Coop, why wouldn't those pull out as easily as the threaded inserts? I only have 3/4" of spruce and the skin to attach my fenders to. If they are to be mounted permanently, I'll mount them before I put on the inside paneling. I'll countersink carriage bolts into the framing from inside, sticking outside far enough to go through holes in the fender inside face, and put on nuts with lock washers behind the tires. Then, if necessa;ry, the fender can be removed and replaced if they get damaged.

[goldcoop]

Coop, why wouldn't those pull out as easily as the threaded inserts? I only have 3/4" of spruce and the skin to attach my fenders to. If they are to be mounted permanently, I'll mount them before I put on the inside paneling. I'll countersink carriage bolts into the framing from inside, sticking outside far enough to go through holes in the fender inside face, and put on nuts with lock washers behind the tires. Then, if necessa;ry, the fender can be removed and replaced if they get damaged.

Dale-

You're doing the right thing, by planning ahead and using the blind carriage bolts, etc.

Insert nuts are only a couple of course threads deep, it doesn't take much for the wood to fail around those large, shallow holes, especially in soft woods and into end grain...forget it!

With the hanger bolts it's all about getting as much depth as possible/feasible to increase "purchase", no doubt if one used a SHORT hanger bolt it would fail as well...

Just my experience...

Cheers,

Coop

[Ira]

Thanks, Coop. "Kind of" the same idea, but you're right--no way for these to come out. A question though:

How do you drive them in? I didn't notcie if they were slotted or anything.

[cracker39]

Ira, one way (the way I'd do it) is to put two nuts on the bolt part, and tighten then together using a wrench and socket. Then, use the socket on the outside nut to screw the wood thread portion into the wood. Then, use the wrench and socket to separate and remove the two nuts.

[Ira]

We got a side cut:




We got FOUR cut:



(Thanks Andrew!)

Next step...tomorrow I take off work and go early to the boatyard to get my wheel clearance measurement (and measurements for my front cabin cabinet). Then off to HD to buy appropriate blocking lumber for the fenders and a SMALL bottle of GG to start sticking those suckers together.

(It's also St. Patrick's Day--so gee, where else can I go if I have some time?)

Andrew's design calls for just two "bulkheads" fore and aft to connect the sides. They run up and down--basically a width of lumber that will accommodate my wheel clearance. It then calls for two 1/8" top skins on top of each other (1/4" won't make the curves), but...

I'm concerned about exposure of the side edges of those top skins. (They won't take the dye like the other surfaces.) The easiest way to do it is just to lay them on top of the fender sides, and the heck with those edges being exposed. The other way to do it is add a little blocking down off the edge of the sides, so I could lay the skins in there and the edges will be hidden. For me, I think this latter method would be real difficult, cutting that skin to the right width, but who knows? I may get lucky.

Yeah--I'll get lucky with ONE fender, and the other will look like a Salvador Dali painting. (I have no culture--those paintings look weird, right? Or am I thinking of Picasso?)

What do you guys think?

Finally, I don't have ANY kind of clamps that will handle holding the top skins down while the glue sets. How the heck do I do it?

[TomS]

Softwood does not hold insert nuts very well.

These nuts are fairly short and don't have alot of purchase in the wood.

If you really tighten up these fender mounting bolts they may just POP out the insert.

I used T-nuts for my fenders. I was worried about them popping loose. So, I put a tiny patch of electrical tape over the screw holes to protect the threads and epoxied them in place with Bondo wood epoxy.

If I had it to do over again, I'd either use hanger bolts or find a way to attach the fenders directly to the frame.

[Ira]

(Tom, I just came back from laughing my a** off after reading your latest Commandments post.)

Why the heck I didn't think about just going into the frame is beyond me, but I would have to take a look down there. That's spring hanger territory, with a LOT of steel to drill through and very tight spaces to tighten stuff.

[TomS]

(Tom, I just came back from laughing my a** off after reading your latest Commandments post.)

Why the heck I didn't think about just going into the frame is beyond me, but I would have to take a look down there. That's spring hanger territory, with a LOT of steel to drill through and very tight spaces to tighten stuff.

I considerd mounting them to the frame. I even bought a set of mounting rods to do just that. However, the spring hangers and and bolts were in the way. There was no clean way to mount them to the frame.