Locating Screw Holes

[gogittum]

Getting close to water time for the 16 ft Starcraft refurb. Finished the trailer yesterday and now on final steps for the boat.

One that's not urgent, but will make a big difference for burning my butt when I sit down is the seats. It has, of course, aluminum seats but the screws are still in place from where the previous owner pulled the wood overlays off the seats, then put the screws partway back in....prob'ly to avoid losing them.

Anyway, I've bought some 1 x 12 edge glued composite boards at Lowes and will stain and varnish them, then install them over the aluminum. Rather than drill new holes, if possible I'd like to use the existing holes - but how to precisely locate them ??

Seems to me, IIRC, years ago I saw some things like small screws that had threads on one side and a short spike on the other. Screw them into existing holes, lay the board over them and whack the board with a plastic dead blow hammer or similar. It would leave dimples in the underside that precisely located where to drill new holes.

Guys at the local Ace Hardware looked at me like I was crazy when I asked about them.

I tend to overthink things badly on a project like this, so wonder if any of you have suggestions ?? I'm thinking to take screws with the same threads and cut them off to an adequate length, then grind points onto them. Screw them into the existing holes, put the board in place and whack as above. Need to make a jig to get them all at an even height but should work. There are 6 holes per board/seat that look to be about #8.

 

[MrGiggles]

Your idea would work fine, tedious, but any method is going to be.

Only other thing you could do is make a template out of construction paper or thin cardboard, tapping around the bolt holes would likely leave a good enough of an imprint for you to go back and knock them out with a hole punch, then use the template to mark your board.

 

[DaleH]

Wouldn't a BB or small marble or ball bearing placed onto the hold do the same thing? An impression might show up better too, if you put tape on the back-side of the board.

But uhhhhhh ... that plastic board doesn't have the strength wood does, so precisely 'what' material willbe holding the seat on?

You could also use 1/4" Togglers, which are a SS 'toggle' bolts, that a least will grip to the tin and hold fast.

....

 

[lckstckn2smknbrls]

I've seen it done on wooden boats.
Using a compass pick and mark 2 spots on the boat set the compass to have the arcs cross at the hole, set the new wood on the bench then using the compass from the 2 marked spots the arcs should cross over the hole.

 

[silentbravo]

What you were looking for is called a "T-nut" very commonly used in upholstery. They attach from the backside of the wood, so they can't pull through, and then you thread your fastener in from the frontside. Pretty much all boat seats (or any small upholstered small seats) with a wood base use these.

That would probably be the easiest way, then you don't have t match factory holes or drill new holes in the aluminum (other than how you are attaching the new material to the original seat?). You would just be fastening the seat to the board to the seat base.

 

[gogittum]

What you were looking for is called a "T-nut" very commonly used in upholstery. They attach from the backside of the wood, so they can't pull through, and then you thread your fastener in from the frontside. Pretty much all boat seats (or any small upholstered small seats) with a wood base use these.

That would probably be the easiest way, then you don't have t match factory holes or drill new holes in the aluminum (other than how you are attaching the new material to the original seat?). You would just be fastening the seat to the board to the seat base.

Yah, I'm familiar with T-nuts, but step 1 is to mount new boards on the entire aluminum seat, then mount the seat to that. Locating the existing screw holes in the new boards has to be precise. Ball bearings/bb's would likely work, but with 6 of them on a less-than-perfectly-level seat, it may be very difficult to get them to stay put while moving the board into place, then banging on it.

Then mounting the swivel seat base to the seat or the board will be a struggle. When it's attached to one, there's only about an inch of clearance between seat bottom and the board. Not enuf room to get my big paws in there.

So far, plan A is to mount the swivel to the seat, then lengths of 1 x 3 wider than the seat to the other half of the swivel and lay them crossways along the seat/board. Bite the bullet, drill new holes and screw them down.

 

[gogittum]

Update. I went to Lowes and found some....laminated ??....edge glued ??....1 x 12 x 6 ft for a reasonable (in this day and age) price, about $20 each. I sanded the 1st one and took the sharp corner off the upper edge, then stained it, then put the 1st coat of polyurethane on it.

I was amazed at how well it came out. Just cheap ol' white wood, but it took the stain well and the varnish really made it pop. Haha.....makes the rest of the boat look kind of crappy now. :-(

As threatened, I cut the heads off 6 matching screws, held them in vice grips and ground the cut off ends to points, then screwed them into the existing screw holes from the old boards.

I then "very carefully" set the shiny new board down onto the "pins" and located it exactly where I wanted it, then used a cushion block and heavy hammer to whack the board down onto the pins. No worries - they punched right in with no movement.

Wal-lah. Ve haff success. I'm extremely pleased with the way it came out and the screw holes lined up perfectly with no searching or hunting. Gonna hafta do something about that ugly transom now, eh ?? Now, just 2 more to go.

 

[gogittum]

I've said it before - I really hate the b.s. photo insert function on this forum. Seems like the 1st pics never insert and show up at the bottom. Ruins continuity. Oh well, should be able to figure it out.

 

[silentbravo]

Looks real nice. Just have to make sure every single image you upload is inserted "inline", otherwise it just piles on at the bottom. Just found that out the other night, was confused as to what was happening for a while...

 

[gogittum]

Looks real nice. Just have to make sure every single image you upload is inserted "inline", otherwise it just piles on at the bottom. Just found that out the other night, was confused as to what was happening for a while...

I've been doing just that but consistently the 1st picture won't insert, then the following ones are fine.

 

[gogittum]

I am really bummed. I got all 3 seats finished late yesterday with 2 coats of urethane varnish. Last night it rained and some water got under the seats and soaked up....and I didn't varnish the undersides.

This morning I pulled them off and 2 seem OK, but the 3rd has de-laminated in several areas. I'm not really set up for and don't have room to properly try re-gluing and clamping it, but will see what I can do.

Then I'll have to coat the undersides as well and live with the idea that they may come apart at any time. What a burn. $20 each for those boards and a lot of work fitting and finishing them. The idea that they may have been laminated with water soluble glue never entered my mind and I'm really pissed off.

Putting the center seat back in with 3/16 steel shank pop rivets turned into a headache. My pop riveter took every ounce of strength I could muster up with both hands to pop just one rivet. I had many to do. Pulled the plastic covers off the handles and put cheater pipes on them.....and promptly bent a handle. Those rivets are tough.

Checking online, long handled, heavy duty pliers are in $50 range plus freight but Harbor Freight advertised similar for $20 and said they're in stock in the Crystal River store, about 25 miles from here, so I went for a look-see. They're very heavy duty, beautifully made and at this point I could care if made in bloody China. (actually, I didn't even check to see where made - still don't know) I bought one and brought it home.

Boom - job done. The thing works beautifully and even has a catch bottle for the pulled stems. I'm satisfied.

 

[Alvarez1112]

A little late as always, but the tool you were looking for in your original post is a set of transfer screws. They're great to have around the shop! They can be had from many tool retailers online as well as Amazon.

 

[gogittum]

Haha....thanks. My home made ones worked just fine on all 3 and, I have no doubt on #4 when I re-do it. It's not save-able, tho' the other 2 will be OK. I will coat the bottoms too, now.

 

[thill]

I'm late to the party, but was going to say that you already had the answer in your original post.

I was wondering how that wood was going to hold up. Hopefully, it flattened out after it dried, and you could patch them up. They sure looked good in your first picture.