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Cutting straight lines

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Forum topic by Knothead62 posted 12-16-2010 05:55 PM 4227 views 0 times favorited 19 replies Add to Favorites Watch
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Knothead62

2581 posts in 2422 days


12-16-2010 05:55 PM

Topic tags/keywords: tip question trick

I’m working on a project for my grandson, an art center as he loves to draw. However…....I can’t cut a straight line for anything. Most pieces are fair but many have a wavy side/sides. I used a jigsaw and moved very slowly. The JS is about 45 years old and I have to hold it at a slight angle to cut straight. I even used a saw guide on a piece of scrap to see if that would work. It was worse than freehand!!!! I don’t have a cabinet saw (wish!) or a router table. The JS has a new blade that works great. BTW, powersaw wasn’t any better.
Any tips are greatly appreciated as I’ll have to take pieces and sand them down for proper fit. Needs to be done ASAP as Santa is stopping by Dec. 24th to deliver it. ;)

All donations for a cabinet saw are greatly appreciated. (Should I hold my breath?) lol


19 replies so far

View DonH's profile

DonH

494 posts in 2279 days


#1 posted 12-16-2010 06:16 PM

I have used a jig saw to cut straight lines in odd places. First you need a good blade – check out the Bosch blades that slice rather than chop the wood (I forget the name for them). Second, clamp a fence in place the appropriate distance from your cut line so that the blade cuts where you want. Finally, keep the saw tight to the fence and push it along slowly so that the blade does not bend back too much – careful with any side loads as that will give you a straight but angled to the bottom cut.

In my experience this will give you straight lines that are very clean (the Bosch blade).

Hope this helps.

-- DonH Orleans Ontario

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Sawkerf

1730 posts in 2530 days


#2 posted 12-16-2010 06:37 PM

Is that “powersaw” a circular saw? With the right blade and a solid guide, you should be able to get near cabinet quality cuts with a typical circular saw.

Use a “finish” blade (more teeth) on the saw, support your workpiece, clamp down a straight guide, and make the cut using slight pressure against the guide. Don’t overdo the pressure toward the guide – it might try to move. Use just enogh to keep the saw base against it.

-- Adversity doesn't build character...................it reveals it.

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Kevin

462 posts in 2667 days


#3 posted 12-16-2010 06:47 PM

I think you would benefit from a good straight edge from Lowes, about 10 bucks I believe for one. A nice circular saw for 30-40 bucks from Lowes or any other hardware store that you can find at a good price. With those two tools, like Sawkerf said you should get some nice straight cuts.

Getting a nice straight cut from a jigsaw is pretty hard to do anyway, I can usually get a fairly straight cut freehand, but nothing like a circular saw with a straight edge.

Good luck,

Kevin

-- Williamsburg, KY

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Knothead62

2581 posts in 2422 days


#4 posted 12-16-2010 07:29 PM

I used the straightedge from Lowe’s with the jigsaw (antique Crafstman that belonged to my late father-in-law). It has been handy but not today! I have a good circular saw (power saw). I’ll have to experiment with blades to get a good cut. I bought a 150 tooth blade for the B & D for clean cuts in paneling and plywood but I’m using 3/4 plywood and that might be the part of the problem. JS blades are Porter-Cable, 10 tpi.

Thanks for the replies. I’m sure there will be more. LJs are a great bunch of folks!

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Kevin

462 posts in 2667 days


#5 posted 12-16-2010 08:11 PM

Ok, good deal then. I completely understand where you are coming from. I most of us started out that way, makes you appreciate the more expensive tools later on.

When cutting plywood I usually just used a 80t blade with the circular saw. Put the good face down when cutting. You can also put blue painters tape across the wood where you intend to cut and it will not leave much chipout also.

We have a big lots here where I live and sometimes I can find those f-bar clamps 24” long (3 for 5 bucks or so) so I stock up on them. I would take your straight edge, if it’s the one i’ve got also, 2 pieces and silver. Measure from the edge of the saw to the inside of the blade. Mark front/back and clamp the straight edge there. Place the saw and see if the blade lines up with the marks. Take some painters tape if you want and tape the line. Now with the circular saw keep a steady pace while you put slight pressure against the straight edge and cut away. Use goggles to prevent the sawdust from getting in your eyes also.

Now if you’re using a jigsaw with the 3/4 wood it’s gonna be a little slow cutting because you don’t want to force it.

Hope that helps some.

Kevin

-- Williamsburg, KY

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Knothead62

2581 posts in 2422 days


#6 posted 12-17-2010 03:37 PM

Kevin, thanks for the info, as well as thanks to the others. I find it very frustrating as I am a perfectionist and have a technical background where we worked down to ten thousandths. Going to have to get used to looser specs. I’m going to see what can be salvage with a bit of sanding and recut if needed. Big Lots has some good bargains! We used to get a lot of our groceries there but they cut the grocery section way down and added furniture. More profit, I would say.
BTW, used to live in Louisville and Willisburg, KY. And folks, the grass is really blue!

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canadianchips

2346 posts in 2458 days


#7 posted 12-17-2010 03:55 PM

As above. Use a new sharp blade. Go slow, let it cut.Keep the pencil mark on the same side of blade at all times. You can consider using a hand plane to straighten the edges ! A properly sharpened hand saw will cut straight as well.

-- "My mission in life - make everyone smile !"

View 8iowa's profile

8iowa

1546 posts in 3223 days


#8 posted 12-17-2010 03:55 PM

Knothead:

I too am working on a Christmas project for my daughter, a sewing table. One of my “challenges” was to cut out a 12”x24” insert in the 3/4” birch plywood for the sewing machine.

I used a Skill jigsaw with a fine tooth blade, covered my cut line with masking tape, and clamped a board parallel to my cut line to guide the jigsaw. I got good results.

For the best cuts with a hand held circular saw on plywood look for a Hi ATB blade with a hook angle less than 10 degrees.

-- "Heaven is North of the Bridge"

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Chiefk

163 posts in 3233 days


#9 posted 12-17-2010 05:15 PM

Knothead, If you have a router, you can use it with a straight edge to get the cut you need. I would use a straight edge to draw a line along along you desired cut line. I would then use the jig saw and cut just proud of the line. Then with the straight edge clamped to the workpiece use a flush cut router bit with the bearing riding on the straight edge. I see that you list SE Tennessee as you location. I live in Crossville, if you are not too far away, you are welcome to bring your project over and cut it at my shop. Just send me a pm. pkennedy

-- P Kennedy Crossville, TN

View Kevin's profile

Kevin

462 posts in 2667 days


#10 posted 12-17-2010 06:25 PM

You’re welcome Knothead62. I too have a technical background along with an articstic background all my life. I’ve had to overcome the perfectionist side within me with my wood also. I am still extremely picky, but I understand that it’s not perfect though.

I’ve been to Louisville a few times. I once thought Lexington and Louisville was a busy town until I drove downtown Nashville and Atlanta a few, lol. Once you get back home to Williamsburg, it’s just so calm and peaceful seems like.

It’s always good when a fellow LJ like Chiefk offers invitations like that :) I will actually cut some parts a tad longer 1/4 so it’s 1/8 longer on each side then use a flush trim bit to flush the cabinet sides. So much easier than trying to get the cuts exact to begin with.

Good luck and let us know how it works out.

Kevin

-- Williamsburg, KY

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Knothead62

2581 posts in 2422 days


#11 posted 12-17-2010 10:45 PM

Again, many thanks for the help! I’ll be out and about tomorrow. Will stop at Lowe’s and see what they have in a blade with 80 teeth as Kevin mentioned. Kevin, know what you mean- makes the term “gridlock” come to life. When I moved back to Tennessee in ‘88, I thought I would like to live in Knoxville or Atlanta but scratched them off the list when I saw the traffic! Don’t care to spend half my life in traffic. Bad enough just passing through.

View D_Allen's profile

D_Allen

495 posts in 2245 days


#12 posted 12-18-2010 01:48 AM

Well, just a thought.
If you are going to be at Lowes, perhaps you could get them to cut a 2’ x 4’ pieces of ply to your desired size.
I realize that this may depend on how good the employee is and how willing to be helpful.

-- Website is finally up and running....www.woodandwrite.com

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Knothead62

2581 posts in 2422 days


#13 posted 12-18-2010 02:10 AM

Again, great info! I have a almost a full piece of plywood from this project. The materials list stated a 4 X 8 piece of 3/4 plywood. I had two pieces, 4X4. However, I used part of one for a project for the other brother. Used on half on this project. So, I have almost a half sheet of plywood to work with. First, I’m going to see what can be salvaged without losing critical dimensions. Or keep the pieces for something else. Anyway, I’ll use the remaining plywood and cut to a bit oversize, use the factory edge as a guide and cut on my tablesaw. I should have done this first but I’m not the brightest candle on the cake! When I get my shop set up sometime this century, I might try to add extensions to one side and the back of the TS to cut larger pieces of wood, sort of like a cabinet saw. Or…....sweet-talk the Mrs. into a larger/better tablesaw. Wait, her birthday is in February….I think she needs a new TS! ;)

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D_Allen

495 posts in 2245 days


#14 posted 12-18-2010 04:44 AM

Well then OK. I didn’t realize you have a TS, just not a cabinet saw. I have a BT3100 and that is by no means a cabinet saw. But I do cut some larger pieces of plywood.
Typically I cut them oversize with a circular saw. Then I use my panel cutting jig on the tablesaw. I use mine like this image with the guide to the back. There are many versions of this. Do a google search on the words ‘panel cutting jig’. I used a piece of 1/2” MDF and once it is set correctly you can get very good, square panels.

-- Website is finally up and running....www.woodandwrite.com

View Kevin's profile

Kevin

462 posts in 2667 days


#15 posted 12-18-2010 08:49 AM

Looking forward to seeing how it turns out Knothead62. :)

Kevin

-- Williamsburg, KY

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