Jigsaw for Curved Cuts

[Steve Friedman]

I am trying to make some Adirondack furniture using a jigsaw (Bosch Barrel) for the curved parts. Obviously, I don't have a scroll saw or band saw - otherwise my problem would be solved.

I have read on SMC about using a jigsaw to get close and then a router with a template bit to cut to the line. So, I started making hardboard templates, sanding to the line with a 1" belt sander. The amount of dust (hardboard sawdust?) was outrageous. So, my questions:

1. It's really difficult to make accurate cuts with the board hanging over the edge of the workbench. For my circular saw, I love the support you get by using rigid foam under the boards, and was wondering if anyone had found anything equally effective and simple for a jigsaw.

2. To get as close as possible with the jigsaw, it would be nice to be able to invert the jigsaw into a table (like a router table) and move the board instead of the saw. It seems like these may have existed in the past, but I ca't find anything current. Maybe they were too dangerous, but I thought I would ask anyway.

I suppose I could just get a 10" band saw, but space is an issue and I keep reading about the relative inaccuracy of the smaller ones. Since I'm using 4/4 cypress, I assume a scroll saw would work as well, but the cheaper ones seem . . . cheap.

Any suggestions are greatly appreciated

Steve

[Jamie Buxton]

.. It's really difficult to make accurate cuts with the board hanging over the edge of the workbench. For my circular saw, I love the support you get by using rigid foam under the boards, and was wondering if anyone had found anything equally effective and simple for a jigsaw...


Don't insist on making the whole cut in one pass. Clamp the board to whatever -- say two sawhorses -- with support crossing the board in two places. Cut from one end as far as you can. Turn off the saw. Move one sawhorse and its clamp on the board. Do more cutting. Repeat.

[Devon Shannon]

Steve,
I think I know where your coming from. I used my Bosch jigsaw for all curve cutting before purchasing a bandsaw. and it worked reasonably well in think stock. No matter what you do, cutting curves with a jigsaw you always have the risk that the blade deflection will result in cuts that aren't quite square-especially in thick stock. However, if your going to templet route these edges anyways, it won't matter. If your stock is a hardwood several inches thick the blade will deflect too much to cut tight curves accurately.

If you clamp the boards to your bench you should be able to cut with accuracy. It helps to clamp as close to the cut as possible, to eliminate vibration, and if there is a lot of vibration I think any jig saw will preform poorly.

I tried inverting an old craftsman Jigsaw once, but It never was worth a dam, because I didn't have more control than I would get with the saw in my hand.

When cutting curves that count, I try to use a new blade if possible. For tight curves, the blade needs to be the appropriate size and toothing. I figured out what blades worked for my curves, by purchasing a verity pack and putting them all to the test. Some of the blades didn't work well for anything I was doing.

[Rich Engelhardt]

To get as close as possible with the jigsaw, it would be nice to be able to invert the jigsaw into a table (like a router table) and move the board instead of the saw. It seems like these may have existed in the past, but I ca't find anything current. Maybe they were too dangerous, but I thought I would ask anyway

McGraw-Edison - Shopmate Saber-Lathe.
Made until somwhere in the early 1970's.
I bought mine in 1971.
Lord only knows where it is now.
It was never much of either a lathe or a saw.
Flimsy is an understatement.
The head and tail stocks were off by about 1/8", and the cheap sheet metal saw table was nowhere near flat.
IIRC - I paid about $40.00 for the thing. Maybe less since I was pretty dirt poor back then.

(IMHO) Not any more dangerous than Lawn Jarts....:D
LOL!

[Steve Friedman]

Thanks for the responses. I know that there are boards (fret boards?) to use for cutting shapes with a fret or coping saw and thought there might be something similar for jigsaws. I think I'm OK with cutting the actual pieces because the 4/4 stock is rigid enough, but the templates I am making are from 1/8" hardboard and the board vibrates and wobbles unless there is some support near the cut line. Maybe the answer is to make the templates from 1/4" or 3/8" plywood that would be rigid enough to cut cleanly with the jigsaw. More expensive, but I guess they'll last longer.

Steve

[Larry Rasmussen]

1. Support board with 6-8" hole in it so you have support on all sides as you cut, just set it across the sawhorses, boxes or whatever.
2. Buy the most expensive Bosch jig saw blades, sorry name escapes me but they are noticeably better.
3. Drill the heck out of the board you are cutting, don't be proud- go every couple inches in areas you know are going to be difficult. If you have a drill press match some of the curves with a hole saw if possible.

Hope something there helps-
Larry R, Seattle

[Brian Kincaid]

2. Buy the most expensive Bosch jig saw blades, sorry name escapes me but they are noticeably better.


All good advice from Larry but this one in particular. The good Bosch blades from Home Depot turned my nice DW jig saw into a good and useful tool. (stock blades were... disappointing)

By the way the tool you describe mounted into a table upsidown is a proper jig saw. What we use is actually a saber saw, but convention has called them jig saws since before I was born.

-Brian

[Steve Friedman]

Thanks Larry. That makes sense.

As for the blades, please let me know if you remember. I am using the small narrow 20TPI one, which is supposed to be for clean curved cuts. I have others, but this is the narrowest and finest cutting one made for wood.

[John Thompson]

Did just what you are referring to yesterday on a 48" piece for a flat screen TV stand. I simply open my LV twin screw wide enough to put the cut line between the jaws then clamp one side to the front jaw opened and the other side to the front lip of the bench with the back jaw. Been doing it for years. The pic below was done with a Bosch barrel cut to about 1 mm of the line.. template mounted with carpet tape and a 1 1/2" pattern bit on the router table. 1 1/4" thick stock with Bosch Extra Clean blade.

BTW.. sorry for the out of focus picture as I shot it quickly. The edges look ragged but trust me.. they aren't in reality! Off to the shop... :>)

Good luck...

[Steve Friedman]

Thanks John,

I was looking for an excuse to spring for the LV Twin Screw Vise!

[Lee Schierer]

Using a jig saw to cut curves is possible; however, blade selection is the key. You have to make sure that the blade can cut the desired radius. For example the Bosch T-234 blade makes excellent cuts that are as smooth as any TS cut as long as you are cutting relatively straight lines. It will deflect and burn badly if you try to cut even a 12" radius. The reason it gives a smooth cut is that the set on the teeth is between the teeth like a Japanese saw and not outward like a regular hand saw. The kerf width is nearly identical to the thickness of the blade. To cut a curve a blade needs to be able to twist in the kerf, so a wide blade with no clearance in the kerf won't turn a corner well. When cutting tight curves you need a blade that is relatively narrow with teeth with lots of set and therefore will get a less smooth cut.

[John Thompson]

Thanks John,

I was looking for an excuse to spring for the LV Twin Screw Vise!

The twin is a wise investment Steve. Extremely versatile.. I am in the shop daily and amaze myself at the ways I have found to use it. Many cases of nothing else would work. BTW.. I have two pieces of 24" x 72" 3/4" ply screwed together and I cut a rectanglur hole 3" x 48" in the center lenght-wise. Sit it between two portable saw-horses as mentioned and clamp it. Then clamp your piece down so the cut line is over the rectangular hole. That worked well when I built a very large computer desk-hutch several months ago with some very long curves.

Again.. good luck and remember... where there's a will there's a way! ;)

[Victor Robinson]

The good Bosch blades are the Progressors...

http://www.amazon.com/Bosch-T234X-Progressor-Blade-5-Pack/dp/B0000223FW/ref=sr_1_1?ie=UTF8&s=hi&qid=1278636191&sr=1-1

[David Cefai]

In Europe we can get jigsaw tables which support the blade at the tip.

See: http://www.wolfcraft.de/jcatalog_generated/en/products/product_groups/37_product.html

However it seems that they are not available in the US. Note that the depth of cut is only about 1 3/4" since the blade must always remain within the support.

In the worst case you might be able to order from Europe but delivery times may be long.

[Steve Friedman]

As a follow up, the inverted jigsaw idea didn't work for me. I built a jig to create an inverted jigsaw that looked something like the attached, and in the process, may have discovered why the concept isn't too popular. Everything worked as intended, so that the inverted jigsaw "table" provided excellent support under the board I was cutting. The problem is that it left the top of the piece unsupported. Unless I held the board down tightly enough, the blade would send a check of the board flying. Since I was trying to move the board, the only way to support the top was with my fingers. Unfortunately, getting the board to sit tightly enough required me to get my fingers way too close to the blade.

Thanks for everyone's help.

Steve

[Alan Schwabacher]

The blades are the problem.

You do need to use a narrow blade for very sharp curves, but it is incredibly easier to get a cut without sideways deflection with a bigger blade. I got a bunch of those small ones, and remind myself every now and then why it is I don't like to use them.

The progressors are excellent, and will cut very nice gentle curves, probably to a smaller radius than you'd expect. Only try a narrow blade if you have confirmed that a wider one won't turn sharply enough.

[Don Alexander]

a hand held sabre saw is not designed to cut mounted in a table upsidedown

the reason you have trouble that way is that the saw is designed to cut on the down stroke when held upright as its designed to be when you mount it upside down in a table it obviously cuts on the upstroke which pushes the wood up off the table

all tools work much better if they are used in a manner consistent with the intended use in conjunction with the proper blade/abrasive or whatever is appropriate for the tool and application

a sabre/jig saw is (like any other type of saw) dependant on proper blade selection

[Lee Schierer]

Don, my Bosch jig saw cuts on the up stroke....Take a look at these teeth, they are obviously made to cut on the up stroke.http://ecx.images-amazon.com/images/I/61XKWMM551L._SS500_.gif

[Will Overton]

... saw is designed to cut on the down stroke when held upright ...

If that were the case you'd have a hard time holding the base of the saw down, against the wood. Take a look at your blades, it's the blade that determines whether it cuts on the up or down stroke. So, even upside down, the blade tries to pull the saw and the wood together.