Radial Arm Saw Setup

Acheiving square, accurate cuts on a consistent basis. May 10, 2005

I am setting up a Delta radial arm saw for my brother. He wants to have an extended table and a good fence with an adjustable stop. He is having a problem with the saw coming out of square. Any ideas on how he can set this saw up with a good fence that produces accurate repeatability and is more consistently square?

Forum Responses
(Cabinetmaking Forum)
From contributor F:
Radial arm saws are not known for extreme accuracy. If he gets the saw as close as he can to cutting square to the table and fence and builds some adjustability into the fence, he can do alright. I use mine for rough cutoff and make my finish cut with a sled on the table saw.

From contributor J:
Ditto on the above post. Radial arm saws are notorious for holding their square setup for about three cuts. I would also suggest cutting rough lengths on it and getting a good miter saw for finish cuts. The problem with the setup on the RAS is that the fence is almost always in some way separate from the saw itself. If you can somehow attach your table/fence to the saw table frame, you will be better off.

From contributor M:
I agree with the others, but this might help you. You must square the saw to the table! No fence. There are screws that mount the table to the under rails - loosen these enough to shift the table to the blade travel. When it is square that way, lock it down and then you can put the fence on. Also, before you do that, make sure that the blade is square to the table vertically! I use a framing square off the back edge of the table, mark a tooth on the blade, and tap it (the table) until I just touch that tooth full in and full out on the arm travel.

From contributor D:
Find the manual for the saw. It will show you how to set the saw up and the sequence. First step first, or squareness, camber and level will not be achieved. If you follow the manual closely and remove all looseness in column (adjustable screws), then it will remain quite true. However, it is always wise and basically necessary to check squareness to fence with square before making important cuts, and the cut part itself with square (using the same edge as was against fence) - you'll learn what it tends to do after it's moved from angle to angle and such - kind of like knowing how to start some old car that requires one tap on the gas before cranking. Delta should be able to send you the manual for your model or one similar, which will illustrate the steps involved. Once that is done, you can extend the fence using a string or long straight edge for alignment.

Another suggestion - a solid core door makes a wonderful table - use full length or cut to needed size. And yes, if your stop is working off the fence, be sure it is attached to table and will not shift as you tap your parts against the stop, thus shifting the entire fence and ending up with a cut that is too long. And last, a groove where fence and tables contact will help reduce sawdust and small things from getting behind the parts you are about to cut, causing unsquareness. A gap there works well also, allowing dust to fall completely through. Contact Maya for adjustable stop considerations - not cheap, but have several models, many great for gang cutting.

From contributor T:
Sorry to disagree. I have an old Craftsman RAS that I bought new about 1971. I built a 16' long bench that the saw sits in and I adjust the saw to the table - not the other way around. I've readjusted it once in 3 years when I had a kickback and everything went down the toilet. Other than that, it's dead nut-on. Mind you, it stays at 90 degrees. I never set it for angle cuts.

From contributor R:
My RAS is a 14'' Maggi. I only use it for cross cutting, panels and lumber. I would not attempt a cabinet job without it. I can cut 16 rails for my face frames in one pull of the saw. I can cut my base backs and wall backs on 30'' uppers. I don't bevel with it, I don't cut angles, and I don't ever try and rip with it. Ripping will cause the blade to run up on material and warp the arm. I will put the squareness of it against any P2P or CNC or panel saw. It stays square because I leave it square. I cross cut a 30'' back and my cut is squarer than the end from the factory. Throw a framing square on it and it's perfect to the naked eye. That's good enough for me. Better than plywood factory is fine, because I darned sure am not going to square sheet goods before I cut them. A 10'' or 12'' home shop saw may not cut true. If the arm has a bow sideways, your blade has to follow it.

From contributor W:
I have a Delta 16" RAS that can crosscut 24". I took my time setting it up on a bench around 30 ft long that's bumped out wider where the saw is. What I did was build the table around the saw and bolt it down square to the table. I then attached my 2x4 rail system with angle iron that's built for shelving - predrilled with holes and slots. I used threaded inserts to bolt down the fence, which give me adjustment in the fence to fine tune for square. I've had it set up for over a year and it's still within 1/64" of square on 24" gables. It's also simple to use a 24" gable to fine tune it.

From contributor T:
Here's my setup. It has replaceable inserts in the table (for tearout reduction) and fence (to register the cut quickly). In the front shot you can see some of the adjusters.

Front shot:

From contributor F:
Two other tips:
1: Make a separate fence about as wide as the saw itself that can be adjusted and replaced. The extension fences on either side can/should be set back a bit from the "main" fence (a fence the width of the saw is long enough to register the material to be cut accurately - the extension fences serve to clamp stop blocks to).
2: Run a wire rope cable from the saw carriage to the wall and down through a pulley. Attach a weight to the end. This will keep your saw from creeping and also keep it from climbing through a board.

From contributor R:
Here's the stop I made from a Jet Exacta fence. Not a tiger, but it's dead on and the adhesive measuring tape makes it simple and easy. My saw has stop nuts and bolts for micro adjustments. Regardless of what folks say about a RAS cutting square, they will stay square. You can't compare a home shop tool or an abused and worn tool with a new industrial grade tool.

From contributor W:
It's true that an industrial RAS is a completely different animal. My delta 16" is so powerful and smooth it's hard to believe.

From contributor M:
Regarding the above post about having a space at your fence, I put in a 3/4 spacer 1/4" lower than the table surface between the table and the fence. That way, no sawdust gets between the work piece edge and the fence.

From contributor S:
Contributor R, I love the table saw outfeed doubling as the infeed on the radial arm saw. You never have to lift your material a second time after it is ripped, and that Jet Xacta fence for a length stop looks tough. Does that oversized bag on the dust collector really help? Your setup looks like a real money maker.

From contributor I:
Has anyone had dealings with the Original Saw?

From contributor P:
We have one of the Original Saws in a shop with 10 cabinetmakers - it is a very heavy duty machine, nicely made, and seems to stay in adjustment. We recently added a Tiger Stop to it and wow - that is an awesome combination. We only cut 90 degrees. It might be finicky if everyone was changing it all the time.

From contributor O:
I would have to disagree with many of the responses to your question of squaring your RAS. I don't know the shape your RAS is in. If it has been abused, you are probably right that it won't cut square. I have a top line Craftsman that I bought new about 15 years ago. I have yet to readjust the original setting for squareness. I not only crosscut but also do quite a bit of ripping. I can now hear the moans and see the wide open eyes at the suggestion of ripping with a RAS. Done properly with feather boards and hold downs, it is a very reliable tool.

Anyway, to set up your RAS, just follow your manual. A Delta is generally a quality machine. If you don't have a manual, you can download one from Delta. It is really important to square your table with the arm first. Then your arm with the fence and make sure all your stops are tight.

From contributor L:
One possible source of your problem is the situation involving your fence. If your fence is curved or wavy, you will never get the arm square because one cannot generate a 90 degree angle from a curved surface. If the fence is not perfectly flat and straight, it will produce the very problem you have. I suggest that you joint the back edge of your table - the one the fence rests against and any other edges which may come into contact with the fence. Then joint one side of your fence and plane the other side of it. This will ensure that your fence is actually a flat and straight plane. All other fence shapes will cause the saw to cut out of square.

The same thing will happen at your table saw if its fence is not flat and straight. Only after the fence is flat and straight for its entire length will you succeed in squaring the arm up to it. You may then use any of the several good procedures already mentioned by others to finish squaring the arm to your now flat and straight fence. Maybe this is the reason some of us donít have this problem. Our fences may already be flat and straight from the start.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor B:
Iím not so sure that RAS's are known for their accuracy. When set up properly, they are incalculably valuable for cross cutting squarely, running dados squarely (that you can see while you cut), and making compound angle cuts. I wouldn't even consider trading my RAS for a sliding miter.

Comment from contributor H:
The assertion that "radial arm saws are notoriously inaccurate" is a popular rant. My guess at the reason for all this is that there are a ton of later model Craftsman saws out there, poorly set up. Even properly set up, these saws have trouble with consistency due to poor adjustment systems and arms made from stamped sheet metal beams, vice the robust adjustment mechanisms and cast arms you find on older Craftsmans, Dewalts and Deltas. Then, as one contributor correctly stated, you must do the set-up adjustments in order.

My Dad bought a Dewalt in '64 and has adjusted it twice, once when he bought it and once when we moved in '69. I had a "high end" 80's vintage Craftsman and ended up giving it away after a year or two of fooling with it. I have an older Dewalt now. Another thing to consider is what kind of shop you have and what kind of work you do. If it's half of a one-car garage and you make a lot of small stuff, I'd rather have a radial arm saw because it sits against a wall as opposed to the middle of the floor and rips small pieces just fine. Are they great for ripping sheet goods? Well, no, a tablesaw does that better, but does that mean a tablesaw is a superior tool overall? Maybe not if every crosscut you make requires a jig the size of a mortar mixing barge.

As far as setup goes, I can't agree with "squaring the fence to the arm," in fact, I'm not real sure how the heck you'd even do that. Start by ensuring the table is parallel to the arm. This is particularly critical if you're going to cut dadoes with it, which I do because it's not a blind cut, like it is on a tablesaw. Also, your fence should be held in the saw table's clamping feature, not fixed, that way you can remove it and slip in a 45 jig. It's often quicker than moving the arm and allows you to use a spacer in the table so you can reposition the fence to the back for wide cuts. Make sure to square the arm to the fence - it's usually one of the simplest adjustments. The bottom line is to buy a good saw, and set it up in accordance with the manufacturers instructions.

Comment from contributor V:
I've operated a Craftsman 10" cast-iron RAS since I bought it new in 1974 and itís worked like a charm. Yes, like all RAS's it needed careful adjustment to set it up initially and regular TLC to keep it that way. In my opinion, however, most if not all complaints about RAS use stem from improper set-up or from saws that need re-adjusting. I've used my saw continuously in my home shop for all my needs - including ripping. Only once in over 30 years did I ever have a piece of wood being ripped caught by the blade and get fired back towards the in-feed side of the table.

Comment from contributor A:
I own two Dewalt radial arm saws and one delta RAS with the center mounted arm. All are older saws, and all are cast iron. They are as accurate as any table saw I have ever used and in my opinion, much safer. I owned a craftsman once and could not get it to index for love nor money. Poor design. The key to the RAS is using the right blade, proper mounting of the saw to a good solid long table, and building the adjustment for tilt back to front and side to side into the table. I rip with my RAS all the time, and never have a problem, but I prefer to rip on a band saw, as the blade is traveling dead perpendicular to the table.

Most people I have met simply do not know how, or do not want to take the time to properly make their radial arm saws accurate. The older Dewalts and Deltas have massive cast iron arms that were aged before finishing, and the motors run on purpose made ball bearings. Mine have zero play even after 50 plus years of service. These saws were ahead of their time in the 50's and apparently still are. Thankfully, blade technology has caught up with them.

Comment from contributor K:
I would suggest getting a copy of "How to Master the Radial Arm Saw" by the late Wallace Kunkle. It is specific to the earlier DeWalt saws, but provides in depth instructions for table and saw setup. Additionally, it provides excellent instructions on how to safely make all of the cuts the saw was designed for. I picked up a copy when I bought a '63 DeWalt a couple of years ago. After setting up the table and making/checking the recommended tool adjustments, I found it cut accurately in all blade orientations. The RAS has pretty much replaced my table saw, except when I need to make a new sacrificial cover for the RAS table (go figure).