Circular Saw Rip Guide--My Version

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Introduction: Circular Saw Rip Guide--My Version

About: I miss the days when magazines like Popular Mechanics had all sorts of DIY projects for making and repairing just about everything. I am enjoying posting things I have learned and done since I got my first ...

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. 

Step 2: Attach With Screws

I chose to have the saw base ride on the smooth surface of the Masonite. So, the rough surface will be down on the finished guide. Here you see the two pieces inverted for assembly. I measured so the screws would form a line down the center of the guide. A screw is installed about 1 to 2 inches from the end. Then I placed screws every 8 inches. The heads are countersunk so they do not scratch a finished surface in use.

Step 3: Trim the Excess From Both Sides

Once the Masonite has been attached to the trim board with screws, invert and support the assembly on enough sawhorses that it does not sag. 

I positioned the edge to be trimmed away off to one side so that the saw will not cut into the sawhorses and metal roller support shown. Make certain the cord is not restricted. With one smooth movement hold the saw base against the trim board and move the saw the length of the saw guide to trim away any excess.* Notice that I clamped the assembly to the sawhorses with "C" clamps so I did not need an assistant while cutting.

I loosened the clamps and turned the assembly end for end. Then I clamped it again as before and trimmed the second side. That gives me the advantage of two edges that mark the cut. If one is ever damaged, I still have another.

*My saw has no "run out" that I can determine. On some saws, especially lower-priced saws, the blade moves outward a tiny bit when the saw is powered up. Cutting in one smooth motion is to eliminate the effects of run out. I will use this guide most often on cuts much less than 8 feet long. I have decided to guard against any run out by starting the saw an inch or so away from the cut line and move the saw base toward the edge of the trim board as I move the saw forward to begin the cut. I will also move the saw away from the trim board before the blade stops spinning. 

Step 4: In Use

One of the frequent problems with clamping a straight edge for guiding a circular saw is that the "C" clamps obstruct the movement of the saw by colliding with the motor housing.* But, the Masonite on both sides of the trim board means I can clamp the rip guide by means of the Masonite on the side opposite of the saw cut, which is yet another advantage of my version. The "C" clamps are far out of the way, and the guide is securely clamped in place. (You can see a piece of 1 x 2 in the lower left of the photo. It is functioning as a cushion piece to protect the finished surface of the door so the clamp does not leave a mark. Also, the left rear corner of my saw's base is cut at a diagonal, which explains what you see in the photo.)

*If you watched the YouTube video linked in the Introduction, the author of that video cut the piece that guides the saw to be extra wide to allow his small saw to clear the clamps. Too much width increases the weight of these guides. The version I made weighs 14 pounds, but provides two working edges. You will need to make your own choice.

Step 5: Trim

Align the edge of the Masonite with the cut line. After the guide has been clamped in place, make certain the cord is out of the way. Start the saw and trim the excess from the panel or door.

Step 6: Finished Cut

The photo shows the bottom of the door after it has been trimmed. Notice how neatly and smoothly the cut edge follows the edge of the Masonite.

Years ago I purchased a two piece aluminum saw guide for ripping. It deflects a little in the middle and I always had to buttress it from the side. Even then, it was not completely satisfactory. This guide from Masonite and an MDF trim board is so much better. When I need to cut something less than 8 feet in length, I just allow equal portions to hang over at the ends and it all works very well. 

I stand my rip guide against the wall when I am not using it. After a while it will begin to bow a little. That is not a big problem, but I can also turn it over periodically so the new position takes out the old bowing. After a while I will need to turn it again.

This guide is made to be used with my saw and the blade I currently have on it. A different saw or a different blade can introduce variables and should have their own custom constructed guide. Also, using this guide with a different saw could render it useless for my saw. If you lend your guide, lend your saw and blade, too.

I wish I had known about these rip guides years ago and had used one then instead of making do with improvised guides that often left "C" clamps in the way of the saw's motor housing. I am also glad I was able to make mine without buying two sheets of plywood.

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49 Comments

I hang mine from a screw in the wall of my shop. Really helps keep it straight and flat.

1 reply

That is a good idea. My shop has also usually been a garage with two cars parked in it, too. Any wall space has many things of various lengths standing against it or it has pegboard with hooks on it.

Hi Phil--great instructable (and nice job replying quickly to everyone's comments!)

Two questions:

1.) I have a piece of aluminum angle "iron" (a 90 degree piece about 6' long). It appears to be very straight (that's why I bought it). Do you think this would be an adequate substitute for the MDF? It's 'faces' are about 1.5" tall.

2.) If I was going to use this guide to cut a 45 degree bevel (to make French cleats), would I need to modify the guide in any way, or just shift it further from the desired cut-line to account for the angle?

1 reply

Ryan,

I think your aluminum angle could work. It may flex sideways a little in use. I would still mount it to Masonite with screw bolts every few inches to eliminate the possibility of flexing for straighter cuts. That also allows the edge of the Masonite to define the cut line for easier setup. One reason I like the MDF is that it has a low profile and the saw motor can pass over it without obstruction. The higher profile of the aluminum angle will likely get in the way with many 90 degree cuts. A 45 degree cut for French cleats should not be a problem.

Excellent instructable. I used a metal guide for years and almost always had to clean up the cut edge on my table saw (never easy with a very long board). The more woodworking I do the more I appreciate the many jigs I've built that make the job easier and safer.

1 reply

Thank you for looking and for commenting. I hope you can use it. I do not use it often, but it has been handy when I needed it. I wish I had had one of these years ago.

This is a nice design and just what I was looking for. One limitation to be aware of - the 1x4 under the motor housing may not allow the saw to be set to it's maximum depth of cut. While this isn't a problem for most applications, it limits the depth of cut just enough that this jig won't work on a 1 3/4" wooden door, at least not with my saw. A thinner piece, such as 3/8" plywood would allow just enough clearance for my saw to make the cut. Nevertheless, this setup is super easy to make and super handy for most ripping applications, and I'm glad I made it. I wound up just using the edge of the Masonite base as the guide for trimming the door. Thanks for the nice design! I wish I'd had this guide years ago.

1 reply

Saws do vary. The 3/4 inch 1 x 4 works fine at maximum depth with my saw. As shown, I was able to trim a door with my saw and a 3/4 inch guide strip. The usual design for one of these jigs involves fastening the machine cut edge of one sheet onto another sheet of material possibly of another thickness. That results in a cutting guide with cutting on one side, not two sides. In my experience the clamps pose an obstruction to the saw. With two cutting sides, one can be used for clamps and there is no obstruction to the saw motor. Your comment about wishing you had one of these years ago reminds me of some custom cars I have seen. The seats are so low to the floor that a person is too old to get in and out of them by the time he is old enough to afford one. Thank you for looking and for commenting. I would be interested in seeing a photo of the one you built.

Luella, I am sorry to hear about your friend's injury. Power saws can be dangerous. Learning about safety precautions is very important. I find it helpful to set the depth of cut to the minimum needed. People actually hold the wood from below with their fingers in the path of the saw blade. Keeping the depth of cut as shallow as possible means an injury from unsafe practice would make a flesh wound rather than cutting fingers off. Stand off to the side a little so you are not in the pathway if the saw kicks back. Make certain the blade guard works properly. Keep the power cord out of the way so you do not cut into it. Do not support the weight of the saw by the part that will be cut away and fall off. Do not let long hair hang down near the spinning blade, and keep loose clothing away from the saw. Do not set the saw down until the blade has stopped spinning. Unplug the saw when you are not using it, even between cuts.

I am having difficulty understanding why you were not able to use this successfully. Perhaps a friend with experience using one of these saws can help you master using this.

I tried it, but it does not succeed, it is a difficult skill. My friend- Daphene, He even injured while using saw :'(

Even if you have a table saw this is still an incredibly good idea to have. Generally speaking table saws are pretty useless for ripping down WHOLE sheet products unless you have some monster table. I'm going to use the table saw to get the 1x4 as straight as possible then attach it. I'm still more worried about making the piece on the underside square to the whole unit. If it's off even by a 1/16, because it's so small, over 4' that could be a big impact. Framing square might help.

1 reply

Just make the thin bottom piece larger than needed and rip it. No squaring is needed then, the straight edge of the 1 x 4 guide will make the edge of the thin piece parallel to the guide.

Use a string, preferably a chalk line to snap a straight line on the bottom piece. Use it as a guide when attaching the 1 x 4. That will make sure any error is very, very tiny.

I would be concerned that a 1 x 4 of real wood could warp a little with changes in humidity. Wood always does. That is part of why I used a composite. Those are very stable dimensionally.

Remember that the machine chit edge of a piece of plywood is very straight and true, and easily available.

Can I substitute masonite with another material?
What would you recommend to keep that straight edge?

1 reply

I am sorry. Somehow I missed your inquiry. You could use Masonite. If you have a factory cut sheet, slice on four or so inches and use the factory cut edge as a guide. Make certain it is thick enough that the saw base does not ride up onto it, but stays alongside of it.

Great Idea! I used some extra laminate flooring I had laying around because I like the surface on both sides and it was free. The straight edge goes right over the joint of two pieces. I made a 50" one with the intentions of making 2 and locking them together for 100" for storage purposes but I can tell that the locking system will take so much abuse it wont last. So I will be making and 8' one as well.

Thanks for the idea though saw it last night and said I have to have one.

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3 replies

Thank you for looking and for commenting. Yours looks good. I think I mentinoned I bought a rip guide made from aluminum more than 30 years ago. It is in two pieces. One of the big flaws is keeping it straight and from moving at the joint when in use. You will like the 8 foot version.

It is amazing how simple this is that I never thought of it before. I have always used a straight edge but have always just figured out where my marks needed to be to make up the difference for the saw. I guess it was never so cumbersome that it turned into a "there has got to be a better way" to make me think to much about it. This will save so much time and even more so a math mistake and a miscut. I almost feel like I own a track saw.

You make me wish I had thought of the original idea rather than adapted it to make one inexpensively and to suit my needs better. It is almost a little like a track saw. It certainly does reduce the chance for error in how far to set off a rip guide. I hope you enjoy it for a long time to come.

I made an instructable for a similar thing, but seeing this you method seems much cleaner and less time consuming when done. Im sold on it and will build one soon. thanks

1 reply

I hope you enjoy the one you make and it serves you well.