Radial Arm Saw Table Alignment -- an Easier Way

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Introduction: Radial Arm Saw Table Alignment -- an Easier Way

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 ...

This is my 10" Craftsman Radial Arm Saw, 1972 vintage.  It is very important that the arm is exactly 90 degrees to the fence at the back of the saw table.  Note the square.  Pull the motor along its travel and see if the blade teeth follow the edge of the square exactly.  It is quite common that a gap between the blade teeth and the square of a few thousandths of an inch will form as the saw moves back toward the end of the arm.  This will cause inaccuracies in any precision cutting.  The owner's manual gives a recommended procedure for aligning the saw, but it is difficult and does not work well.  This Instructable will show you a much easier, much more precise way.

Step 1: The Factory Recommended Procedure

The recommended procedure involves loosening and moving the arm in its mount.  Remove the two screws on the angle scale at the top of the column and remove the aluminum disc on which the angle scale is printed.

Step 2: Loosen the Mounting Bolts

Under the aluminum disc inside the column are two bolts.  The heads are 9/16".  With a wrench you are to loosen them just a little.

Step 3: Bump the Arm

After the bolts inside the column have been loosened a little, you are to bump the saw's arm a little and check the blade travel with the square again.  When the arm is square to the fence, you are to tighten the bolts inside the column.  Put the aluminum disc back in place and everything should be good again.  

But, it is very difficult to bump the arm without bumping it either too much or too little.  There is a much easier way.

Step 4: Adjust the Table With Precision

There is an easy way to move the table rather than the arm and move it just a little so the edge of the table that holds the fence in place is exactly 90 degrees away from the blade's travel on the arm. 

Step 5: Loosen the Table Hold Down Screws a Little

When loosening the hold down screws for the table a screwdriver is required from above and a wrench to hold the nut below.  Loosen the four screws in the table just enough that you can move the table, but it is not too sloppy.

Step 6: Make Two Small Blocks

Cut two pieces of 1 x 1 wood 1 1/2 to 2 inches long each.  Get two 8 x 32 machine screws about 1 1/2 inches long.  Drill a hole through each block just a little smaller in diameter than the screws.  This hole is the black circle in the graphic.  Thread the screws through their holes so some of each screw extends on both sides of its block.  The yellow circles are optional holes for mounting screws.  Glue may be sufficient in most cases.  These blocks will be mounted on the underside of the saw table.  (See the next step.)

Step 7: Mounting and Using the Blocks With Screws

The photo shows the blocks with their screws mounted in place under the saw table.  The tips of the screws rest against the frame of the saw.  With the table hold down screws loosened (Step 5), push the table forward so the screw tips rest against the saw frame.  Tighten the hold down screws slightly.  Secure the fence against the front edge of the saw table.  Place the square as shown in Step 4 and check the alignment by pulling the saw motor down the arm to check the blade travel against the square.  If adjustment is needed, as it surely will be initially, loosen the table hold down screws a little and turn the 8 x 32 screw in one of the blocks in or out a quarter turn.  Tighten the hold down screws and secure the fence again.  Check the blade travel against the square.  After a few tries, the blade travel will be perfectly 90 degrees from the fence. 

Where these blocks become very useful is when you must take down the saw for moving to a new workshop.  But, they also make the initial setup easier and more precise.  One day you may need to replace the saw table.  These blocks will make alignment after that job easier, too.

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    46 Comments

    I just bought this saw, its particle-board table top was destroyed, so i went all out and built a rolling 6' long table its also taller to accomodate my height.

    Question:
    1. How do i fix the blade brake? I currently use a piece of scrap to slow the blade.

    2. Also is there a better dust catching method? Seems the forward vacuum hose only catches half of the sawdust

    image.jpeg
    4 replies

    I have never serviced the blade brake on my saw, although I know it is less effective than when it was new. I always expected I would order new parts from a Sear's parts depot. It may be possible to improvise with available materials.

    I do not know of a good solution to the dust problem.

    Your table looks really good.

    Thanks. I need to make cabinets for one of our rooms, so quick built this from lumber left over from a project. The blade stay pretty accurate, but not perfect. Some panels seems to be about 1/16 off, but most stay perfect. Seems a random problem.

    A very small amount of sawdust between the work and the fence will introduce an inaccuracy. I missed that more than a few times when I started using a radial arm saw.

    i will keep a better eye on that. Thanks. I may need to lengthen the right side of my bench, so i can place blocks so all my carcase side pieces come out the same.

    I recently purchased a used Craftsman RAS. Everything works well but I cannot move the arm from the 90 degree position after releasing the latch. Could the index pin be seized in the 90 degree position? Any ideas?

    1 reply

    I can only guess. I suppose that is possible, but even then, the arm should have a little play in it right to left and vice-versa when the knob is loose. If not, remove the cap over the column as in steps 1 and 2. There may be rust between the column and the arm. Let some penetrating oil soak in and give it enough time and enough oil. Some tapping with a hammer may help.

    I recently purchased this exact saw, but for the life of me cant figure out a few of the knobs and adjustments. Do you mind answering a few questions?

    1)What is the green knob/pull for on the saw above the word Craftsman?

    2)What is the black knob with the yellow ring for on the front?

    3)What is the pull/handle for above the black knob with yellow ring?

    4)How do I change the mitre angle on the saw side to side?

    5)How do I change the angle of the saw itself for cross cuts?

    Thanks for any help you can provide.

    1 reply

    This will be a very brief answer to get you started. The maker of the saw color coordinated the colors on the knobs with the angle scale indicators related to that knob's action, so, the green dot on the chrome spoon handle on the motor yoke releases the motor yoke. Then raise the indexing pin with the green knob and swivel the yoke to one of the other available positions. All knobs, levers, and angle indicators of the same color relate to the same adjustment. Let me know what is still a puzzle after you study the colors and the items of the same color.

    When I cut with my 1973 sears 10 radial arm saw, my cut is clean across the top surface, but ragged on the bottom side. What adjustments do I have to make?
    john hermosa

    2 replies

    John,

    I assume you have this problem when you pull the motor carriage toward yourself to make a cut (make a crosscut). If you were making a rip cut (motor turned parallel to the fence and pushing the wood across the table into the blade) you would notice the bottom surface cuts cleanly, but the top surface has some roughness and splintering where the blade exits the wood.

    Any circular sawblade on a power saw will do this whether it be a radial arm saw, a table saw, or an electric handsaw (also known as a circular saw). The reason is that when the teeth cut entering the wood the fibers are being pressed down into the rest of the wood as the cut is made. But, on the other surface the teeth are cutting as they exit the wood and they pull some of the fibers with them to cause splintering and a rougher cut.

    You cannot eliminate this problem, but there are ways to minimize it by means of strategy and some controls. Most wood projects require a good side and a side not really seen after the project is finished. When crosscutting you can plan your work so the side that needs to be good is cut as the teeth on the blade enter the wood. With your radial arm saw that would mean the good side is on the table facing upward as you pull the motor carriage back on the saw arm.

    Make certain your saw is properly aligned so the blade does not heel. If it does heel, there will be a tendency to splinter as the teeth exit the wood, even on a cross cut. (Rip cuts on a radial arm saw are made with the teeth exiting the top surface at the leading edge of the cut. Normal practice would be to have the good surface down when cutting if at all possible.)

    Using a finer blade (a blade with more teeth) reduces the splintering you mentioned. So does pulling the motor more slowly for a slower cut. Cutting with the grain reduces splintering while cutting across the grain increases splintering. Using better quality woods with a tighter grain pattern reduces splintering, while cheaper open grain woods tend to splinter more when cutting.

    Some sensitive cuts, like cutting across the grain on veneer plywood, can be greatly improved by scoring the cut line with a straightedge and a sharp knife, but this requires aligning the scoring knife mark very precisely with the path the saw blade will cut.

    I hope this helps you.

    One way to minimize the problem is to use a backer (like a thin plywood) under your cut (under your entire work piece to keep it level. Then as with a new rip cut, you have no existing kerf cut void under your work in which to lose wood fibers. The underlayment supports all of your work so as to virtually eliminate edge splintering. You'll get a very clean cut as it holds the edge grain while cross cutting just as with a virgin rip cut in a new RAS tabletop.The wider the kerf cut under your crosscut work, the greater the potential for splintering. I made this discovery when I replaced my cutting table top in the middle of a project and saw the marked reduction in splintering. Now I frequently use a backer on fine cut work.

    I have a similar saw and it is not cutting square. It is 1/8 of inch off and is set on 0 Any tips

    1 reply

    Do you know the concept of taking the play out of each adjustment by consistently nudging each adjustment in the same direction each time? If you set up the saw with the "play" in each adjustment nudged out in a clockwise direction, you need always to nudge the adjustment in a clockwise direction each time you use that adjustment. Even then, every saw, whether a table saw or a radial arm saw, will go out of adjustment during use from vibrations, etc. Periodically, every saw must be aligned again. It is also a good idea to check accuracy of adjustments before doing especially critical work.

    I once cut two six-sided tops for end tables. Everything went well until I got to the sixth corner. It was always a little off. I even used a feeler gauge to move the arm a few thousandths of an inch with the saw motor pulled out as far as possible. Still, it was off just a little because a very tiny amount of error was cumulative over the six cuts.

    Another thing is that your square may be off a few thousandths of an inch. That is why I like to lay two squares of thin plywood over each other. Cut what should be a 90 degree crosscut. Flip one of the pieces over so the two cut edges are against one another. With the other two edges of the 90 degree corner firmly against a straightedge, check to see if the two edges against each other meet evenly or whether there is a slight "V" gap. The error is half of the "V." Adjust the saw until the edges meet evenly along their length.

    I have a 10" Craftsman RAS a little newer than this one. 1980 , I have every thing dead on except the 45 bevel. The detent is at 46 and I have to manually use a speed square to lock it in a 45. Know of any way to adjust the detents so the saw clicks in at exactly 45 degrees?

    1 reply

    The detents always have a little play in them. An old principle is that you always set up all detents so the play is taken out in the same direction before locking the adjustment. I set up mine to take out the play by nudging each adjustment in a clockwise direction. That could be your problem.

    Otherwise, index holes are not adjustable. Once 90 deg. is set accurately, 45 deg. should be accurate, too, unless an indexing hole is worn through extra use. I had that problem with the indexing holes on top of the motor yoke, and did an Instructable on a workable solution. Search for egg shaped indexing holes on a Craftsman radial arm saw.

    Very helpful! I recently acquired my grandfather's radial arm saw and this looks to be the exact one that I have. I'm just not sure on the year of mine. I'm a new home owner and am looking forward to using this saw quite a bit!

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    1 reply

    With a little care in maintanence and in safe use it will serve you well for a long time. I had to replace the motor bearings on mine after a lot of use. The motor switch is prone to wearing out and is not available. I did an Instructsble on replacing it with a switch commonly available at places like Lowe's or Home Depot. Thank you for looking.

    I was going to do this to fine tune my saw, but came across an even easier way. On my craftsman saw, there is a 3 piece table which allows 3 fence positions. The table is clamped together using screw clamps that are mounted to the frame at the back edge of the table. I loosen the mounting screws as described in your article, and use the clamping screws to adjust the table, re-tighten the mounting screws and your done.

    1 reply

    Those screw clamps are what come from the factory. They hold the prarts of the table down, but do not automatically square the fence to the blade. I wanted something precise for squaring the table in very small increments, something I could remove and put back into place without needing to square it again. But, do whatever works for you.