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Best tool for notching?

Posted: Fri May 02, 2008 7:14 pm
by garrys
Here's a really dumb question from a newbie. What is the best tool to use, or the best technique to cut notches in the frames for battens? I'm just starting to build a Monaco.

Garry Stout
Tampa, FL

Posted: Fri May 02, 2008 8:13 pm
by BruceDow

Welcome to the forum...

This is NOT a dumb question... It's one we've been debating on this forum for as long as I have been here... There are a number of ways to do the notches, and we will always argue about which is best...

Here are the three that come to mind...

I tried (but never really mastered) using a router jig. (See Mark Bronkalla's site for details)

I never tried (but always thought it was cool) to make a template, then cut the notches out with a spin saw (roto-zip)

I used a circular saw - set to the right depth - and made enough cuts that I could easily knock the waste out with a chisel.

If you try a search on "notches" you should be able to find some of the details on these methods.

Good luck.


Posted: Fri May 02, 2008 8:47 pm
by Fifty Plus

I like a dovetail saw, make several cuts and clean out with a sharp chisel.
The only dumb question is the one not asked.


Posted: Sat May 03, 2008 5:36 am
by Falcon
just as the fellows said above ,I use a skill saw set to the right depth, the front side likes to split a little if you clamp a block on the fount of the board being knoched it will prevent this also give the saw bace a bigger service to sit on an help to keep the saw from tipping. more cuts easer clean out with a sharp tool.

Posted: Sat May 03, 2008 6:51 am
by John K
I have used jig saw, router, hand back saw, and roto zip. It just has depended on how easy it was to get to place to notch. I usually do not notch the frames until mounted.

Posted: Sun May 04, 2008 7:44 am
by Bob Perkins
I marked the frames with a marking knife, using the batten, so I had a clear reference. Next I clamped a couple of guide strips along the frames and adjacent to the notches.

Using a router with a 1/2" spiral bit (very important!) a straight cut bit will tear out the cross grain. A spiral bit backs into the slot nicely and will not tear out. I had cut just inside the marked line. I preset the bit depth to the bottom of the notch. The guide strips provide all of the angles necessary for the bottom and sides of the notch since they are laid on the hull like planking.

Each notch gets cleaned up with a sharp chisel and a piece of scrap batten.

When I did my notches - I had not faired the frames. I set the router depth so that the intersection of the frame and the batten happened at either the leading or trailing edge of the frame (depending on which frame I was on) I faired the hull after the battens where in place. You can probably fair the frames first and notch after - but you run the risk of losing the reference edge of the frame.

I did not glue any battens (screws only) until the entire hull was faired.

Hope this makes sense.

Posted: Sun May 04, 2008 4:24 pm
by garrys
Thanks Robert, and all who replied. VERY helpful information and as a newbie I really need help!

Quick question.......what does a "spiral" router bit look like? I have a router but not sure if I have one of these. Are they readily available at Home Depot or is this a special order kind of bit?

Garry Stout
Tampa, FL

Posted: Sun May 04, 2008 5:10 pm
by Bob Perkins
They look like this:

Not sure if you will find them at the Depot - here's the issue... They are very expensive. You want a carbide spiral bit (I like Whiteside myself). Mine was over $40.. But - once you use a spiral bit - you will never go back.

The reason they work so much better is they cut with a shearing action instead of a slapping/scraping action. They cost more because they are more difficult to manufacture and the carbides can't be welded on - the whole bit is carbide.

Hope this helps.

Posted: Sun May 04, 2008 6:01 pm
by Jones
I became fond of "japanese" or "pull" saws to make notches... they have a very fine kerf and a few touches with a chisel finishes the job. Routers are great too, but I found in the time it took to set up my router, the pull saw and chisels had the job done.

Posted: Sun May 04, 2008 6:40 pm
by leakcheck
Marking Knife ?? Did you actually say: MARKING KNIFE ??? Hell, all this time I have been using a carpenter pencil from Home Depot !! No wonder I am using so much freaking Epoxy !
STeve :lol:

Posted: Sun May 04, 2008 7:11 pm
by garrys
Why the 1/2" spiral bit? I would think the 1/8" would make for sharper corners in the notches. Do you then use a chisel to true up the corners after removing most of the material with the router?

Garry Stout

Posted: Sun May 04, 2008 7:48 pm
by Bob Perkins
My battens were 3/4"x3/4" (or 1" x 1".. I forget... and the boat is in the shop..) - You could use a narrower bit - but 1/8" would be a lot of extra work.

I just went through my old pics and found the jig I made. I'd change it just a bit so that the bottom plane of the jig had a pair of outriggers that straddled the frames forward and aft of the jig (and frame being notched) to help set the angle of the platform so that the angle of the bottom of the batten notch matched the lines of the hull ... 2TFi5bt2Pg

The blue tape had the marks where I wanted to cut. I planned the layout in tape to avoid screws and to make cuts through parts of the hull that made sense. The area where the stem and motor stringers meet were a bit of a pain as I remember. I still cut just a hair inside the lines and finished with the chisel.

Also - as the hull gets real curvy by the bow - this doesn't work - you have to hand fit the battens. There are a bunch of ways to do this. This worked pretty good for me. I only had to fix up a couple of notches here and there when the final fairing was done.

Question for falcon

Posted: Tue May 06, 2008 2:17 am
by BobL
Hi falcon,

Did you cut the notches after fairing? My frame members are all not in right angle after fairing. Clamping a block in front may not end up a flat top for sitting the saw.