Brunton 70-P compass-pilot holes

[gyork]

Can someone recommend the proper size drill bit for drilling pilot holes to accept the included screws of the 70-P? Thanks.

Gary

I found success using a standard 3/32" wood bit. Before screwing in, I placed a diminutive rubber "O" ring over the screw, such that it ended up between the ?brass plate and the fiberglass. I found 4 of the smallest-sized nylon acorn nuts in one of the "specialty" cardboard drawers at my Ace hardware store. I dabbed the receptive ends with shoo goo and hand tightened the nuts over the screw pointy ends.

Gary

[Jed]

Are you mounting to poly or fibreglass ?

Consider using brass bolts, washers & nuts rather than the supplied screws. Neither plastic nor fibreglass is great at holding screws and the pointy ends will tear up your gear. If you switch to bolts just size the hole so that the bolt slides thru with minimal resistance.

To size pilot holes for screws:

If poly: Hold the drill bit up behind the screw threads such that the bit and the screw are overlaid. Select a drill size that cover's the narrowest part of the thread (the post) but does not cover the threads themselves. You'll need good eyes / glasses for this. A pilot hole of this size will allow the threads to "cut" into the plastic but will not cause the plastic to "mushroom" too badly.

if fibreglass: As above but you'll have to go slightly larger since the fibreglass will not form around the threads. For fibreglass I size my bits such that 1/2 of the actual thread depth (height of the thread from the post) is covered. This way the material that the thread "cuts" out of the fibreglass has a place to go.

if either case: Once drilled, "butter" the bolt or screw with silicone sealant just before you install. The silicone will fill any voids / provide a watertight seal and lubricate the screws bolts for installation.

Cheers,

Jed

The ability to defend our beliefs with absolute certainty . . .

   . . . is often inversely proportional to our level of experience.

[Dee Hall]

An addition to Jed's good advice: if you decide to stay with the screws (not a terrible choice if the tips don't go all the way through the glass or plastic) make sure you don't overtighten the screws while installing. It's just not necessary, and the threads are small so it's easy to strip out the hole. There are unlikely to be large forces trying to rip the compass from your deck. The nice thing about the silicone, is that it will also keep the screws from loosing on their own too.

Also, you might want to check to see that you can get a wrench or at the very least pliers (Visegrips are better) on a nut behind all four corners of the compass recess before you drill that bigger hole. Usually, where there is a will, there is a way, but on the other hand, we don't want to hear about you bashing your Visegrips through the hull in frustration either.

-Dee

[gyork]

Brian if I use brass bolts, do I need to expand (re-drill) existing holes in the plastic housing and thin metal plate behind it? Holes are pretty tiny.

Gary

[djlewis]

And if you do stick with screws -- or maybe even for bolts -- you can disarm the pointy tip with a small wad of epoxy "clay".

That comes in a multi-layered roll. You cut off a piece like a slice of salami and then knead the layers thoroughly together to activate the epoxy. The resulting stuff is the consistency of silly putty, and easy to form into protective covers for the screws or bolts. (Or, if artistically talented, you can form it into little fish, cats, kayaks or other whimisical shapes which harden into statuettes.)

--David.

[Michael_Crouse]

Any advice for a lubber line that has shifted to one side?

I keep paddling slightly off course now ;-)

[Brian Nystrom]

IMO, using bolts and nuts is unnecessary. The stock screws hold just fine in any material. Drilling the holes undersize as Jed suggests for plastic boats is a good idea as the holes will be self-sealing. With composite boats, a dab of sealer (any type under each screw location will do the trick. If the screws protrude to a degree that concerns you, simply snip off the ends and/or put a blob of sealant on them.

[Brian Nystrom]

...then turn the compass until the lubber line is properly oriented. The compass is designed to allow such adjustments.

[mesbennett]

David,

would Epoxy Putty be what you are referring to??

Which I can get at my local hardware store??

maryb

explorer lv railblue/white

mystic yellow/white

[djlewis]

Yes, epoxy putty -- that's it.

http://www.dickblick.com/zz238/17/

and I guess I wasn't kidding about the artistic possibilities

http://polymericsystems.com/kneadatite.htm

http://polymericsystems.com/images/greenstuff.gif

Hmmm... I can see the possibilities... like creative deckline standoffs, and neat figureheads for our bows.

http://seagifts.com/shipfig.html

OK, we return you now to your regularly scheduled kayaking discussions.

--David.

[Brian Nystrom]

...as it could make getting the screws out very difficult, if you ever find the need to remove the compass. This is one of the few places on a kayak where I would recommend a dab of silicone sealer. Other sealers would work just as well.

If you want to use epoxy putty, I suggest using it to build up the area where the screws protude BEFORE installing the screws. Allow the epoxy to harden, then drill and install the screws. If you don't drill all the way through the epoxy, it will prevent leaks as well.

[djlewis]

You really think the epoxy will bond to the metal screw well enough to prevent turning the screw? Also, the torque force you get when you turn a screw with a screw driver is really pretty strong, and it's all shear.

Anyhoo, I got that idea from Tom Bergh, and as we all know, Tom is infallible! ;-))) Actually, I'm about to find out. I'll soon be removing a compass mounted -- with screw tips epoxied -- on a boat I am returning to -- guess who! (But no matter what happens, I still think Tom is a superb source for all things kayaking.)

--David.

[jsmilez]

If you have a plastic kayak, simply use an awl to create a starter hole (dimple really). The screws are so small, you don't really need to predrill. After inserting the screws, I estimated how much was protruding through on each screw, and backed them out 1 by 1 to cut them. When the compass is mounted, there is no way for the holes to leak, or the screws to fall out. I did put a dab of sealant on each screw just to protect my gear.

hope this helps someone, I had to wing it myself. =)

-jay

[djlewis]

Applying the epoxy before the screws go in seems like a reasonable idea -- except that it makes a one-session project into two sessions, with a layover in between. That's not good for lazy procrastinators like me. ;-)))

But is it necessary? The screws came out just fine -- no interference from the epoxy. And we did the same as before on the new boat.

--David.

[Ben Fuller]

If you have problems, heat the screw with soldering iron. Hot epoxy does not hold real well.

Ben

[Brian Nystrom]

...could also damage the fiberglass and the heat required to soften epoxy would melt a plastic deck.

[djlewis]

They come right out. The normal torque generated by a handheld screwdriver is plenty.

--David

[EEL]

>Can someone recommend the proper size drill bit for drilling

>pilot holes to accept the included screws of the 70-P?

Know you've got it done, but for future eference on this thread; a good size drill bit is 5/64 for this application. Large enough to make it easy and small enough to give threads material to bite.

Ed Lawson