Circular Saw Rip Guide--My Version

Rip guides like this one can be found on YouTube and in other Instructables here. They are very handy for precise ripping of large panels and for trimming things like doors. I am including a couple of modifications, though, that I think readers will find very beneficial. One is a cost reduction. A second is no need for making a precise cut during the construction of this guide. Another is a way to clamp the guide so the clamps do not interfere with the motor housing on the saw. The fourth is two working edges in case one should be damaged.

In the photo you see my rip guide prepared to trim 1/8 inch from the bottom of a door. 

Step 1: Materials and tools

Materials

• 1 MDF trim board 3/4 x 3 1/2 x 96 inches 
•  Tempered Masonite 3/16 x 15+ x 96 inches
•  Bevel-headed wood or sheet metal screws: # 8 x 3/4 inch

Tools

• Rule
• Drill with bit and countersink
• Screwdriver
• Sawhorses 

Lowe's Home Improvement Stores in the USA sell painted MDF trim boards in various widths. These trim boards are very straight. Since the trim board will be mounted with screws to a piece of Masonite almost 15 inches wide after trimming, the piece of MDF does not need to be completely resistant to bending under lateral pressure. The Masonite will add sufficient rigidity.

Have the store rip 15 or 16 inches from the long side of a sheet of 4 x 8 feet Masonite. It does not matter if the cut is not completely straight, but the panel saw will likely yield a straight cut. (My saw's base is wider than some with almost exactly 5 inches between the edge of the base under the motor housing to the nearest side of the saw blade. If your saw's base is smaller, the Masonite could be narrower. But, the Masonite needs to be twice as wide as the base dimension on the motor side of the base plus the width of the trim board. Leave a little extra on both sides to be trimmed away.)

I had a car, not a truck, when I went to the store. I had the store cut the remainder of the Masonite so I had two pieces about 33 x 48 inches each. They may not go into a car trunk, but will slide through a rear car door and not rise above the seats to obstruct your rear view on the way home. (The panel saw at my store is poorly aligned and corners on crosscuts are not square. The operator has tried several times to get the management have the saw aligned again, but has been unsuccessful. Be aware.)

Plans for rip guides like this often suggest ripping about 6 or 8 inches from the long side of a sheet of 1/2 inch plywood. This is aligned along the edge of a sheet of Masonite. That means you may be buying both a sheet of plywood and a sheet of Masonite. One advantage to my version is that you buy a sheet of Masonite and a trim board only, which makes for a lower cost. (Also, if you are cutting the piece that will actually guide the saw, you will need a means of guaranteeing that cut is perfectly straight. That may not be possible in a beginner home workshop. The straight trim board will be a big advantage for getting a straight guide without a large table saw the beginner workshop may not have.)

Center the trim board on the long Masonite piece and clamp with "C" clamps. Support this sandwich with enough sawhorses to keep it from bowing. 

Comments

[Moltroub]

Very good instructable Pastor Phil! I truly enjoy reading your efforts. For me, it's like having my father and uncles explaining things to me. Do you think the vinyl trim would be strong enough to be the guide or would it present too much bow to the Masonite?

[Phil B]

Thank you. I am glad you enjoy these things. I enjoy doing them. The trim board I used is not vinyl, but a composite material similar to MDF. It is available in greater widths, like a nominal 6 inches. That is wide enough to resist bowing. I hope that answers the question you are asking.

[Horsehockey]

I use a piece of 1x4 longer than the piece to be cut. My Milwaukee saw is 5 1/2 inches beteen the inner surface of the blade and the outyer edge of the saw base. I mark the piece to be cut at the cut is to take place, measure another 5 1/2 inches back and clamp the 1/4 in place. Using metal spring clamps to secure the 1/4 in place allows the saw motor to clear the clamps.
Simple, fast, and cheap. I cut a lot of 1 1/2 styrofoam board (4x8 and 4x10 sheets) on the ground. A 2x4 under where the saw will run keeps the blade out of the dirt or grass and provides a rigid surface for the cut.
The saw guide dedpicted would be really useful in a cabinet shop but wouldn't last long in a construction site with the foremans whip on a workers back.

[Phil B]

For the last 40 years I have often done what you describe. It always demanded more mental effort from me to be certain I was reading the measurements correctly and making them identical on both ends of the rip guide board. I always wanted something like this and find it much easier with more certain results. But, if you have something you like, go for it.

[mikem360]

i put 2mm neoprene type foam on the bottom, no longer need to clamp it in place

[Phil B]

Thank you for the comment and the idea. I would not have guessed the neoprene foam would be dependable enough to guarantee no movement.

[fjr_scoot]

NICE! Great ideas that I will implement the next time I make one of these

[Phil B]

Thanks. Apparently you have used these guides before.

[coolbeansbaby68]

Very nice phil

[Phil B]

Thanks, Jim. I wish the original idea had been mine.

[coolbeansbaby68]

Thats ok yours looks just as good

[Bill WW]

Thanks Phil, a useful Instructable.

And I like your folding carpenter's rule, don't see these much any more.

Bill

[Phil B]

Bill,

Thank you for the comment. That carpenter's rule was purchased new in 1970. I have used it a lot. The numbers on inside surfaces are still mostly like new. Those on the outside have suffered. Once a friend taught me how to unfold these rules in one speedy and continuous motion. I thought YouTube would have a video, but I do not find one. I may need to demonstrate here it one day.

[Bill WW]

You said: "Once a friend taught me how to unfold these rules in one speedy and continuous motion.".

One of my strongest memories is when I helped my dad install an oil furnace at the family home in Indiana. 1951, I was 10. We were using his folding rule, which I tried to open in a speedy motion, and it broke in half. I was distraught, did not stick around to see my dad's reaction.

[Phil B]

"It's all in the wrist!" The movement involved with both hands needs to be carefully synchronized. If one hand gets ahead of the other, it would be very easy to break an otherwise good carpenter's rule. So far, I have not broken one, although I do not open one in rapid fashion regularly.

[Goodluck]

A few things:

1) I find running the power cord up and over my shoulder does a nice job of keeping it out of the way and keeps it from snagging various things. If the wall with the plug is in front of you, use an extension cord long enough to loop it around behind you, then up over your shoulder.

2) In use, orient your clamps as pictured in steps 4, 5, and 6 (turning part down)as opposed to as show in step 3 (turning part up). Not only does that help prevent power cord issues, it also helps prevents the screw part from snagging clothing or poking you and surprising you while running a power tool (not good).

3) Long ago I realized cutting through the tops of my sawhorses wasn't a big deal (see a photo of them in my Treedle Lathe instructable). The biggest reason being that it supports both pieces after the cut. When they get worn out, I'll just build new ones. The ones I have are roughly 20 years old and I don't feel inclined to replace them yet.

4) Well done, I too wished I had known about such a guide many years ago. Without one, it is nearly impossible to cut a straight line. With one, a very simple operation. The only change I'd be inclined to make would be to glue the mdf trim board to the masonite. Screws may loosen or 'ream out' their holes with pressure and vibration over time.

[Phil B]

You make good points. I considered gluing the two pieces rather than using screws. One version on YouTube encouraged using screws because the edge of the Masonite could become damaged over time (in the estimation of the video's author). In that case, the screws could be removed and the Masonite could be shifted to one side a little. Then a new edge could be cut.

I did not want to cut into my saw horses because one of the supports is a steel roller I did not want to cut with my carbide blade.

Thank you for your comments and suggestions.

[cobber67]

Good idea Phil I am going to start off and make a 4' version as I feel it will be handier for skimming doors

[Phil B]

It is a good idea, but, it is not original with me. Only a few modifications to make it less expensive, easier to build, and more useful are mine.

I strongly considered four foot and eight foot versions, but decided to make the eight foot version and simply let the ends hang over both sides of shorter things like doors. I am not certain how many eight foot panels I will be ripping. Once we owned a big Mercury station wagon, and I could slide a whole 4 x 8 sheet of plywood into it with all doors and windows closed. Still, there have been times when I needed some very specific cuts from a sheet of plywood. Once I bought a nice sheet of oak veneer plywood at a specialty dealer. He let me plug in an extension cord in his parking lot and use my own circular saw to cut as I needed so the pieces would fit into the back seat of the '63 Chevrolet sedan we drove in those days.

Thanks for looking. I hope it serves you well.

[rimar2000]

What a good idea, Phil!

And well done, and well depicted.

[Phil B]

Thank you, Osvaldo.

[woodlina]

As usual Phil, your Instructable makes sense, is well written and will be very useful this afternoon when I start ripping panels for some utility shelves I'm building. Thanks for all the great work you do!! -Alan

[Phil B]

Thank you, Alan. As I mentioned, this idea is not original with me. But, I tried to make some helpful modifications. It will be helpful for making your shelves, especially if you make dado joints in the uprights for aligning and supporting both ends of each shelf. Thank you for your comment.