i need to “cross-cut” a desktop made of 5/4″ sapele that is 8.5′ long by 30″ deep with a straightedge and a circular saw. i want to be careful not to get splintering on the cut edge. is there an appropriate blade (7 1/4″) or manufacturer? i read a finehomebuilding review, but came out more confused than when i started. lol. should i back it with something?
also, i want to put a long radius or “bow” on the 8.5′ length and my jigsaw blade will never stay perpendicular pushing through 5/4″ sapele.
any thoughts?, and thanks
Replies
Given how carefully these edges need to be finished, I would cut them proud by 1/8" or so, and then finish them with a router bit. For the straight edges, use a straight board to guide the bearing along the cut line. For the curved edge, make a template with a piece of 1/4" Masonite and do the same thing. Not sure how you'd make the rough cut for the curved part. I'd try buying an aggressive Bosch jigsaw blade and do a test cut. Cut slowly and let the blade do the work.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
always count on forestgirl!thank you.....now i need to buy a new router bit (that's a good thing)
appreciate it
Although forest girl exudes confidence, 1/8" proud is to my pea brain akin to being really shy. (hey, sometimes the girl won't come out of the forest....(cowtown ducks)1/16" over would be enuf to sand/route to the line....of course yer gonna cut from the underside, and even using a skill saw, I wouldn't use a low-tooth-count blade. My site work saw is an 8.25 dewalt, so I get to use the same blades that are used in SCM saws. Medium to high tooth count, probably ATB (ain't looked in a while)As for the curved edge, I too have experienced the flexing of jig-saw blades, and the more forceful you are with the saw, the more flexing you encounter. Don't use a used blade, spring for a new one if you decide to go this route, a used blade may be dull on one side, and yer perpindicular cut is gonna go more and more astray with such a long cut. there agin, 1/16" off the mark is OK, and then cowtown (and this is just his vision of this task- not the defacto right way to do it...) would take a belt sander and sand down just proud of the mark at a right angle, and then "fair the curve" buy using a flexible sole automotive body rasp. Then hand sand it to the finish you want.Once you put that flex sole rasp on what you thought was a fair curve, you'd be suprised at the "deviations" You know of course that if you undercut the bottom (perhaps with a raised panel router bit) so that the finished edge apears to be only 3/4" thick or so, there is a more delicate appearance to the curved edges- really appearing not only more stylish, but also more delicate , and that your sanding to "fairness" is substatially easier to accomplish. I think that this was suggested somewhere back in the fwwing archives. Made sense to me then, and still does. Just my thoughts. Eric in cowtown..
Both of festools saws would do the trick. The circ has a guide for the straight cuts, no chip out. Their jigsaw has sacrificail inserts that keep chipping to almost nil. A drawback would be that the 2 are gonna cost 800 bucks. Pretty pricey if you're doing only one project. Not so much if you have a long term need.
Hi,Here's how I would do it:Use a 1/2" (or there abouts) router bit and straight edge and rout right on your finish line. Use several passes to get enough depth for a top guided trim router bit to ride on. So you'll end up with a 1/2" but about 3/16" groove. If you have a strong router and sharp bits you could hog this out in one cut. The idea is to make a clean wide surface to guide a top bearing router bit on so depending upon which of those you have or buy.....get it??Now come in with your jig saw or skill saw if comfortable enough and free hand as close as comfortable, 1/16" would be great. Now come back with the top guided bearing router bit and flush trim it to you finish line already established. The bearing will ride on the edge established with the first router cut so that 1st cut determines your finish line....This works great for curves!HTHBro.LukeBro.Luke
THANKS!wanted you to see the result. a couple of things i learned, 1) don't expect spiral bits to "hog" off material,.....take it slow, lots of passes. 2)sapele splinters out (a bit), but is very consistent.here's what i did, i went to lowes looking for some sort of board to "spring"....realized that any natural piece of wood doesn't bend consistantly, (i got dirty looks from "associates" when they saw me bending them in the store...tee hee). so i grab a piece of fake brick mold...pvc i think. it bends maybe a bit too well, so i backed it up with pcs of wood clamped to the opposing side to brace. cut rough with a jigsaw (thank you) and then used a spiral bit (downward) to clean it up, using the brick mold the whole time, a template wasn't necessary. what splintering there is will be taken care of by the round over bit i'm going to use.thanks so much for the tips!
Lookin' good!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Ditto Forestgirl on the router method, I might add to using a spiral down shear on the end grain for a smoother finish.
On the 8.5' bow I would also use a "spring board" That's a 1X2 that's clamped (vertically)at the center of the 8"+ length and the ends sprung back towards the center line and clamped a set distance in to provide a desired curve then where the center clamp is clamp down a brace on the inside of the curve and then remove the center clamp and route along that board. Don't forget to offset the "spring board" from router bit to edge of router. A router with a round base works best. Yikes, I'am better at doing than explaining, hope you followed that.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
Good suggestions all- You will want that curve perfect- I'd use the spring board mentioned above to draw a curve on a piece of MDF. Cut it with jig-saw just proud of the line. use a rasp or file or block plane to faire the curve. Sand it to your satisfaction. When it is perfect- dbl stick tape/clamp it to your table end. jig saw close as you are comfortable-
Then use the router/bearing for a dead perfect duplication.Flip it to the other side- perfect mirror image.1/2 mdf cuts/sands easy-is cheapgood luck
Dave
thankfully, only one side....the other is against the wallgreat tips!
and here i was (you're not going to believe this) figuring out that i needed a 25' radius/string to measure out the appropriate curve.and i thought i was reasonably smart.....thanks for the "spring" board idea....i would have thought of the offset though....lol
Turn the desk top upside down and fully supported.Use a new combination blade in saw, tape and score the cut line only where the saw blade exits.Make the template for the radius with a trammel and router. Allow for a bushing or use a top bearing bit.
Take several light cuts with router until thru.
mike
merlvem,
Not sure how accurate you need the curve but be careful of the springboard method. Wood doesn't usually bend too evenly. Try a bow( with string ) , mark your line , then flip it over to average it out to make your pattern
Paul
Edited 3/17/2007 2:27 pm ET by colebearanimals
Now I would use a Festool t75, cause I got one...lol.
you're right about wood,.....but i figured out a way around it....check out the post....and thanks.
I've had good luck with my present "spring board". But the vinyl brick mold has some potential thoughts brewing. Namely compound "S"curves. Thanks for the brick mold thought, and I already have some in stock.Work Safe, Count to 10 when your done for the day !!
Bruce S.
The smart base from eurekazone comes with zero clearance antichip inserts.
You can use any straight edge and the cuts are the cleanest that you can get with any blade.
It was voted by FHB as the best antichip protection system.
The good thing is that you can get just the base.
I use the Diablo blades.
David
thanks david
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