Handrail installation

[Capn_Tom]

I'm about to begin installing new handrails and am looking for advice. I have a 6,5, and 2 loop teak handrail on each side. The holes for the old rails were filled when I refinnished the cabintop. My plan is to drill a 3/8" countersink and drill a hole for a #10 pan head machine screw in the top of the rails between each loop. I will drill through the cabin top for the first 2 screws and temporarily mount the handrail. I will then attempt to bend the handrail sufficiently to follow the curve of the countertop drilling and placing additional screws as I go. Once all of the screw locations are marked I will remove the handrail, drill a 3/8" hole through the top skin and core, and fill with thickened epoxy. After the epoxy cures I will drill and tap for the #10 machine screws and install the handrail with a flat washer, lock washer, and nut from below.

How much bend can I expect to acheive in a 3/4" 6 loop teak handrail?

I selected the screw size based on the head size. Is a #10 machine screw sufficient for this application?

All suggestions would be appreciated.

[Hirilondë]

I think you will find trying to get a machine screw into a threaded hole while bending the handrail and aligning up the holes while not messing up the bedding to be quite tedious, if in fact the holes do align as well as needed to get into a threaded hole. When installing hand rails I either through bolt them or use regular screws from below, through clearance holes in the cabin top into pilot holes in the hand rail. I pre-drill the holes in the cabin top based on a simple layout by measurement and then through these holes I mark the handrail above. Both of these methods require removing the over head or leaving the fastener head exposed. A third option exists in having hand rails in the over head in the same locations that share the fasteners.

It is key in either case to assure that fastening places loads on the handrail above the cut outs that make up the loops. This is due to grain direction. Other wise you will likely split the handrail at the loops (cut outs) some time just when you really needed to be holding on. If you use screws from below, they should go well into the hand rail and to within about 3/4" of the top. If you use bolts, the counter sink should not go deeper into the hand rail then the same 3/4".

In regards to your bend question, that is hard to answer. Teak doesn't really like to bend much, but hand rails can often be made to bend to match the shape of the cabin top and follow the curve of the cabin sides.

[Capn_Tom]

Excellent points on the threading and depth of screw issues. I'm still inclined to throughbolt incorporating your sugestions. The screws will be aprox. 3 3/8" and countersunk 1/2" into the top of the rails. There will be 7 screws in the 6 loop rail. Is a #10 screw of this length strong enough for the stresses in this application?

[tpl]

instead of #10 suggest 1/4" at least--we used 8mm=5/16" bolts
also suggest cutting slots on the bolt ends so that should they
ever loosen you can hold them with a screwdriver

[Hirilondë]

I'm still inclined to throughbolt incorporating your sugestions. The screws will be aprox. 3 3/8" and countersunk 1/2" into the top of the rails. There will be 7 screws in the 6 loop rail. Is a #10 screw of this length strong enough for the stresses in this application?

I think a #10 is quite sufficient and this plan should work very well. I would suggest locking nuts or lock washers as well. I like Nylock type nuts for marine applications.

tpl's suggestion about the slot seems interesting. I don't think it would work in a #10 machine screw though, not big enough. My other concern would be that if the bolt loosened it is possible if not likely that the bedding of the hand rail is now suspect for leaks and it might be a good idea to remove and re-install the hand rail completely. Just ask any one of the many members how much fun they are having with recore projects if you need motivation in a case like this.

[Capn_Tom]

I'll be overdrilling the holes and filling with epoxy. This should solve any core issues. I appreciate all the guidance thus far.

[Quetzalsailor]

Clamp/bolt your handrail onto something and invent a tool for grabbing it down the line and bend it. See if it will tolerate the bend (I think it would for a typical cabintop handrail). The tool could be a 4-6' -2 x 4 with a pair of transverse and padded blocks. If you worry at all about breaking the expensive things, build a one-off steambox, cook them for an hour after reaching steady-state temperature as close to boiling as you can get (200f is easy in a plywood steambox), pull them out and clamp them to a guessed curve (blocks and a 2 x 6) somewhat greater than required, let them cool and dry. You'd probably do them separately; they only bend when HOT. Protect the wet wood from the steel clamps: rust and dings.

I'd through-bolt and, as the others say, be sure that the head is up in line with the longitudinal grain. Our NE 38 appears to be through-bolted and the on-deck handrails and the overhead hand rails appear to use the same bolts.

[mitiempo]

You don't have to overdrill. Better to drill a 1/4" hole and rout out the core with a dremel. There is more strength if you keep the deck skins as intact as possible. Here's a link with pics step by step. http://www.pbase.com/mainecruising/seal ... eck&page=1
Brian

[Capn_Tom]

Another great illustrated guide! His articles are better than any book on boat repair I have.