Cutting a stright line

[JimNC]

I am making several Dollhouses. I must cut out 7 windows and one door opening out of on ¼” plywood on each house. The windows are about 5-1/2 “x 2-1/2”. I am having trouble keeping straight cuts.

I am not happy with my “prototype”.  I must go back and true-up the openings, which is very time consuming. I have 7 houses to make. Any suggestions?

Edited June 19, 2023 by JimNC

[Rolf]

What blades are you using? There are several blades that have no bias. such as the Olson PGT series and I now use the Pegas MGT blades. 

Practice on the scraps to get a feel for how the blade cuts. I find I cut straighter when I cut a bit faster, but I have been at it for 13 years.

Edited June 19, 2023 by Rolf

[don in brooklin on]

I tell my students that the 2 hardest things to cut are the straight line and a circle.

Steve Good has a good videos on this subject - https://youtu.be/eSO8uXe2NgY

The other video that is good https://youtu.be/iP1kR4ThXuU

He explains it better.

 

[rafairchild2]

I find the key for me is to go really slow on the cut, slow down the blade speed, and really slow down your feed.  I use a 5x magnifying glass, and as I guide my piece I watch the little 'bubble' of sawdust/cut just in front of the blade, I make it split my line.  By going slow I can see what direction the blade wants to travel and I make micro adjustments so it stays right on the line.

 

[JimNC]

1 hour ago, don in brooklin on said:

I tell my students that the 2 hardest things to cut are the straight line and a circle.

 

 

I sure am learning that. Thanks for the info

[rafairchild2]

Here are a couple of other things I do to not only maintain straight lines but also curvy lines.

Along with going slow, I stop frequently and let the blade settle in, you would be surprised at how much pressure you unconsciously add as you move along.

Next, at least with Flying Dutchman Ultra reverse, I keep the "scrap" part of my cut to the right.  I find that my blade cuts and drifts to the right.  This way any errors as I am going along will always be in the scrap area and I can then correct them.

Lastly, I use a 3mm piece of plywood about 1.5" wide and 10" long.  I use this in various ways, but on long cuts, I put it to the back.  This way I have a wider "grip" to steer my wood along the cut line.

Below image 1: is how I use the stick in the back, of course, I would use both hands.  If this was a small piece I might actually have it to the right of the blade to hold and guide the wood.  This also keeps the pattern from lifting up too... bonus!

Image 2: This is how accurate my straight and wavy cuts are.  This is raw cut and other than a quick sanding mop to get any fuzzies off this is prior to any fine fitting. Note, each piece is cut separately, this is not stack cutting or match cutting, but just following the line on each piece's pattern.

Edited June 20, 2023 by rafairchild2

[OCtoolguy]

One thing that I have learned, and I don't recall who told me, but when doing circles or straight lines, try not to look right at the point of contact between blade and board. Focus about 1/4 to 1/2" ahead of that so that you can guide without trying to "catch up".

 

[jollyred]

One thing I found helps me is to adjust my position so that I am in line with the direction the blade wants to go.  This gives me a better look at the direction than if I just sit centered on the saw.  I use a piece of scrap with a straight line drawn on it and try to follow the line.  You will quickly find out if the blade wants to wander off the line (usually it wants to go to the right).  Then I shift to my seat to the right so I am in line with it.  It also helps me to follow curved lines.

Tom

[BadBob]

13 hours ago, OCtoolguy said:

Focus about 1/4 to 1/2" ahead of that so that you can guide without trying to "catch up".

Look where you want to go, not where you are. This works for many things.

 

 

[TAIrving]

Make sure that the tension is set properly.  The blade sometimes slips in the holder and a blade with loose tension will drift off-line.  

Watch the pattern line just in front of the blade.  

Practice, practice, practice.   

[Davevand]

The thing that always gets me is that the blade drift will change as it gets used and duller. I will have a good idea of how much I need to angle the piece to cut the straight line, then I will change out the dull blade for a new sharp blade and the drift will be totally different. This gets me especially at 90 degree turns.

[rafairchild2]

2 hours ago, Davevand said:

The thing that always gets me is that the blade drift will change as it gets used and duller. I will have a good idea of how much I need to angle the piece to cut the straight line, then I will change out the dull blade for a new sharp blade and the drift will be totally different. This gets me especially at 90 degree turns.

Very true, this is why I change my blades frequently.  Remember too that heat affects the blade, thus another reason why I go slow and also use clear shelf liner (lubricates blade) that I put my pattern on.

Remember going slow allows you to watch the drift and micro-correct so you stay on the line.  Also, make sure as best as possible listen to the blade, you will hear more "chatter" as the blade dulls too.

I have given up trying to turn on my 90 degree's, or really any sharp turns, I tend to do a "nibble", turn the blade, line up the next cut to get the most accurate and sharp cuts.

See below how I nibble a turning spot, change direction and away I go.

Edited June 25, 2023 by rafairchild2

[Peter N White]

Can't open your lick.

[rafairchild2]

15 minutes ago, Peter N White said:

Can't open your lick.

Fixed it.

[JimNC]

Thanks for the great help. Mike of Mike's Work Shop suggested some blades that really worked too. Thank for all the feedback.