Bat House Forum

[Terry Lobdell]

[Terry Lobdell]

This is a simple jig I made for cutting saw kerfs in baffles with a circular saw.

[Terry Lobdell]

[Terry Lobdell]

I made this wooden guide for the circular saw to make straight cuts.

[Terry Lobdell]

[Terry Lobdell]

Both the baffles and the jig are rough sawn lumber so minimum clamping was needed to hold them in place. Just one screw in the end board was sufficient to hold all the baffles in place. Smooth lumber would have required more clamping.

[Terry Lobdell]

[Terry Lobdell]

This is a row of finished saw kerfs. They are not quite as straight as when done on a table saw but this method with the jig was very fast and easy. Eventually I hope to get a dado blade set up for my table saw to cut 3 kerfs in one pass at 1/4" intervals.

Although my bats definitely prefer mesh baffles I have had good luck with saw kerfed baffles as well. I will probably make all my baffles this way this year because it is so much faster and costs less.

[Joe Spencer]

Nice Terry!  Kind of like a reverse radial arm saw setup.  Do you have a RIP blade or combo blade in the saw?  I also thought of building my own kerf setup with a cheap high power setup using a 5hp electric motor (already have 220 outlet in my garage/shop) and using washers as spacers between multiple blades on one long shaft coupled to the motor via a belt and pully to eliminate vibrations.  The latter could/shouldn't be direct drive.  In one pass the entire board would be kerfed on one side.  With such a shallow kerf depth and all the weight spinning, I wouldn't expect any bogging down.

[Terry Lobdell]

Joe, it's a carbide tip framing blade. I also tried a plywood blade. With the shallow kerf there didn't seem to be much difference.........

How many blades would you have with your design and how wide of a swath would it cut? 

[Joe Spencer]

Enough blades as possible so as to not bog down the motor at the desired kerf depth I suppose Terry.  For the boards which I use horizontally those could be ripped but of course the verticle smaller/inner chamber boards such as those one might use in rocket style inner chambers, l would have to use cross cut.  Frequently that "made in china" HaborFreight company has 50 percent off sales and carbide tipped blades can be had very cheaply.

[William Bagwell]

Bumping an old thread here, hope that is OK? Wondering if anyone has built a multiple blade kerf cutter yet? I had a similar thought before I searched for this topic but not sure it will be worth trying. 7 1/4" blades are certainly cheap enough to gang a dozen or so together. 4 or 5 passes to grove each side of a baffle is a huge improvement over ~50 passes. Still have to build an improvised machine to hold them all.

Even toyed with the idea of searching for an old horizontal milling machine and perhaps running enough blades to roughen a baffle in only two passes. Sadly a bit too rich for me to afford at the moment

Then it hit me a jointer! They already have a 4 to 6 inch wide blade and are dirt cheap compared to a horizontal mill. And if one is willing to goober up a set of blades by grinding a 1/4" relief every 3/8" leaving a series of 1/8" wide cutting tips... I think it will work and other than being back to the 4 to 6 passes per baffle should be a bunch less trouble than trying to build one that uses saw blades.

William

[po boy]

I am building 8 four chamber bat houses and using 11/32 exterior grade plywood for the baffles. To kerf the baffles I stacked two old steel saw blades using a 1/2 spacer I made from a fence board. To make the spacer, I cut 1.5 plug with my hole saw and then bored a 5/8 hole in the middle to fit the arbor. These were mounted on my radial arm saw. You can use 5/8 washers if you have them on hand and stack to get the space you want.

With this set up I get two kerfs with each pass. When I did a pass I would pass through, reverse the ends, flip the piece and repeat the process. Worked toward the middle since I was reversing the ends. Since I had 24 baffles and the inside of fronts and backs, I would run them all through and move the saw head out one inch using the guide on the arm. Lots of sawdust.

As stated, I used some old steel blades and found that one was smaller than the other making one kerf a little deeper. Guess it had been sharpened a few times. If I were to do this again, I believe I would buy new plywood blades.


Photo of set up.

This photo shows me running a baffle through.

baffle with kerfs

[William Bagwell]

Two blades cuts the time in half, even 50 blades and a single pass would not be as large of *additional* savings. If my jointer idea fails to pan out I will probably do almost exactly what your are doing only with a table saw instead of a radial arm saw.

Found a jointer today that I can use for the cost of a new set of blades. Googled a bit and found a set for $30 plus shipping. 6 1/8" wide so a 24" long baffle would take four passes per side but only *one* change of settings using the same reverse and flip technique you used. Will post pictures if it works.

11/32 is what used to be 3/8... How are they holding up with a grove on both sides? I might try just the opposite from you and make my center baffles thicker than the fronts and backs. Since mine are not the out side exposed to the weather and essentially a one sided baffle.

William

[po boy]

William,

These have not been mounted as I am still painting/staining the exterior.

After I cut the kerfs I sprayed them with a fine mist using my garden hose, stood them on ends in a shaded area for several days to dry. I did have a little bowing, but got that out by stacking them in my workshop for several days with a weight on top.