What can I do to achieve a flush edge, using a jig saw (Bosch), to cut curves out of 2" cedar?
I notice that after cutting a curve, the bottom edge of the cut is bowed out. (the blade is bending) I've tried new blades and creeping slow motion to no avail.
I'm using the widest blade I have that will accommodate the curve.
Finally, (out of frustration) I make a sweep with a close cut to remove the bulk of scrap wood, then another cut on the mark, then the belt sander (80 grit) to pretty things up.
Any other suggestons?
Cher.
Posted by Bruce Bowers (Member # 892) on :
Cheryl,
Mine does the same thing. I also have a Bosch Jigsaw. It came be frustrating to have to go back and clean up the cut.
What we do for multiple copies of the same shape is make a template out of plywood and use our 5 HP router to cut out the shape. No cleanup necessary.
Have a great one!
Posted by John Smith (Member # 1308) on :
Cheryl, I, too, had this problem. I got so frustrated I tossed my cheap Sears jigsaw and got a Dewalt top of the line saw with the "reciprocating stroke". This eliminated the problem somewhat, but not all the way. I have cut dozens of fancy curves in redwood and cedar and still can't get that perfect cut. I think this is something we all will just have to live with. But NOW, I use a hefty 3" bit in my 1/2" router and always get a very smooth perfect cut that needs little or no sanding. I had to get the bit via mail order. The downside of this method is the dust if you don't use a vacuum hood on the router. This is one of the reasons I am totally committed to using HDU exclusively for my signwork. Good luck to ya !!
Posted by Steve Nuttle (Member # 2645) on :
Cheryl, that's why I never use a jigsaw! Never could get a flush cut. Band saws are better but for tight curves and large peices that don't work either. Thank god we have a cnc router. I lay it out in the computer and send it to the router. Even, simple circles. Good luck!
Posted by Joe Rees (Member # 211) on :
Good post Cheryl - I'd sure like to hear how anyone has resolved this problem also. I'm convinced it is a combination of blade and pushing technique, but havn't found the right combo either.
[ February 23, 2002, 11:56 AM: Message edited by: Joe Rees ]
Posted by Luke Scanlan (Member # 2481) on :
Make sure you use the corner blades. There is a difference. I can't remember what the series # is, but if you look at the package it usually shows a small curved symbol. They work much better than the straight ones.
Posted by jimmy chatham (Member # 525) on :
make sure your blade is square to the shoe and let it walk instead of pushing it.
Posted by cheryl nordby (Member # 1100) on :
Hi Cheryl, I just cut a couple of ovals. And found with the first one I was pushing it along. The next one came out much better when I let it go easy and kept my eye on the lines instead of the blade.
Posted by ScooterX (Member # 2023) on :
i haven't tried 2" material, but here's what i've been doing the past couple of months with thinner stuff:
i found that a rough cut with the jig saw followed by a clean-up cut with the router worked best for me. i use a router blade with a pattern following wheen on the end. you might even be able to find one that rounds over the top edge (or even bullnose) at the same time.
yes, it means you need to make a template (from masonite, PVC or 1/4 particle board, or whatever you have on had). the small amount of time taken to make the pattern is saved in the clean-up phase because the router leaves the edges so smooth that there's almost no sanding required. also, you can make the first jigsaw cut more quickly since its going to be followed up.
Posted by Dan Sawatzky (Member # 88) on :
Cheryl
Yer just going the wrong way round...
In the northern hemisphere you go counter clockwise and down under you go clockwise.
Perfect cut every time!
Just ask our Aussie firends.
-dan
Posted by Wayne Webb (Member # 1124) on :
Cheryl, I hate to sound like a salesman but, I have had excellent results using Porter-Cable tools. Our P-C bayonet saw has adjustable guide blocks, just like a band saw does, to optimize blade alignment. It has three orbital settings and the universal chuck will accept any style blade. I sometimes use it to cut shapes in 4'' thick redwood or cedar signblanks with a 5'' blade. The blade does still skew somewhat but does a lot better with the guide blocks.
I usually jigsaw cut about 1/8'' or so from the line and then sand it with a Porter-Cable portable oscillating spindle sander. This baby is really a dream, uses four different drum sizes, and does a fine job of sanding perfect 90 degree edges on any size sign for inside and outside curves.
[ February 23, 2002, 02:09 PM: Message edited by: Wayne Webb ]
Posted by Michael Boone (Member # 308) on :
My solution is to clean up the edge with a good sharp rasp. Redwood is really soft and cuts with ease with a rasp. I just cut a fancy one....2'x8'...3" thickness.... Brand new Bosch jigsaw.They make their own blades and they seem to last a lot longer. It took about an hour to square the edges. Final finish is with a long sanding board with progressively finer paper.
Posted by Jon Butterworth (Member # 227) on :
I had this problem and partly solved it using the finest toothed narrowest blade possible and as previously posted ... let the jig saw do the walking
Posted by Felix Marcano (Member # 1833) on :
I do exactly what Bruce does. Works every time. & as he said, the best part is that you don't have to bust your butt sanding.
Posted by goddinfla (Member # 1502) on :
Being an ex-carpenter I use my skilsaw for any outside curves then use the belt sander to smooth. I make a series of plunge cuts and then sand. Takes about a quarter the time of using a saber saw. Saber saws are hard to get straight down cuts and hard to get a real smooth curve. This is why I use the skilsaw. For inside curves I use my 5 1/2 foot throat bandsaw. Only if I have to will I resort to the saber saw. multiples are done with a router and template as above. The template is done as I described above.
Posted by Santo (Member # 411) on :
Definately the wrong tool. The bandsaw is the thing for 2" or bigger stock, but your gotta handle the wood. The blade has to be getting real hot. The router plunging will work.
Posted by Monte Jumper (Member # 1106) on :
DANS GOT IT...
Posted by Monte Jumper (Member # 1106) on :
Geez Dennis...I have a 3 foot throat on my bandsaw and everyone that sees it is jealous.
But 5 and 1/2 foot? WOW!!!
Ok I admit it I have "bandsaw envy"
Posted by Bill Cosharek (Member # 1274) on :
I'd recommend a bandsaw also; but if you must cut with a sabersaw, try using "hollowground" blades. They seem to stay sharp longer.
Posted by Dave Sherby (Member # 698) on :
Bowing cuts are sometimes unavoidable. This method has worked for me IF the cut is bowing away at the bottom of the cut. First cut with the jig saw. Some light sanding may be necessary to bring your curved cuts right up to your line. Then I clean it up with a hefty 1 inch diameter flush trim bit. The bearing is at the shank end of the bit. Set the bit depth so the bearing is riding at the very top of the blank. The bit will clean out the bowed area. For 2 inch thick stock, you may not clean it all up in one pass, so then lower the bit to finish it off. The bearing will be riding on the area you just cleaned up.
This method works great for matching 2 identicle signs or 2 signs mounted back to back. I finish the first blank as above. The second one is cut near the line. Put the signs back to back and clamp them together. Lower the bit so the bearing is riding on the first finished blank, but the bit is cutting into the second blank. You'll have to move the clamps one at a time to get all the way around. Then you can unclamp the first "pattern" blank and finish off the second one.
Posted by Rick Sacks (Member # 379) on :
the last time this discussion came around I neglected to write down the name of the bit that has the bearing at the top and has an outer diameter the same as the cutting bit. Do these bits come with a spiral cut? Where are you getting them? I like the idea of not needing the template guide set with the collar and needing to cut my pattern 1/8" smaller to compensate for the offset.
Posted by captain ken (Member # 742) on :
I go with the router too, I have a 2" top bearing straight cut bit. You can trim it down with the jig saw, then finish off with the router
Posted by Cheryl Lucas (Member # 1656) on :
Whoa! Lots of input here...
It's comforting to know that the operator isn't solely responsible for a perfectly bowed edge!
Letting the jigsaw 'walk' was more like a crawl, maybe I need more POWER! (insert Tim Allen grunt here)
I need to see the 'straight bit' routing in action, maybe John will allow for some 'hands on' at his Spring Fling - Gathering of Craftsmen!
Got a wish list, and heading to the power tool section at the local hardware store!
Thanks for your input, Cher.
Posted by Nevman (Member # 332) on :
Something that I haven't heard mentioned yet is to clamp/screw a scrap piece of plywood to the back side of your stock. This will eliminate the through-push of the blade.
Also, for simple circles, here's a jig for your router...
Posted by Nevman (Member # 332) on :
Whoops...read the post wrong...I thought you said "blowed out" not "bowed out"...
Good tip anyway Posted by Marty Happy (Member # 302) on :
I've noticed that using an extra long blade seems to help keep a cut square.This was an accidental discovery after having to buy a 6-pack of extra long blades to cut some 3" thick foam. I started using the blades for regular MDO and that is when I made the discovery that they ran truer. Also because only the base of the blade gets any wear leaving the rest of the blade unused, I have snapped it off and ground down the blade so that it would fit the clamp of the jigsaw and have gotten 4-5 uses out of one blade (am I being a cheapskate or what?!?!) and I have noticed that as it gets shorter the blade has more of a tendency to wow especially when forced ahead.
[ February 25, 2002, 04:25 PM: Message edited by: Marty Happy ]
Posted by brian oliver (Member # 2019) on :
Here's a technique that I haven't seen mentioned- I came across this trying to solve the same problem. My Porter-Cable oscillating sabre-saw does the same thing when I'm cutting curves.
When you're following the curve with your saw, don't push it, let it kind of pull your hand along, as the others have mentioned, BUT... as you guide the saw along the line, steer it from the back of the shoe, as if the saw had a rear wheel that steers it. If you've ever driven a fork lift, you know what I'm talking about. In other words, you aim the front of the saw by swinging the back of the saw around.
I've found that if you steer your saw in this backwards fashion, you can all but eliminate the bowing.
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