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Blades for RAS, especially hook angle specs

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  • Blades for RAS, especially hook angle specs

    Will need to replace the blade that came with my RS1000 radial arm saw soon, so looked at the Freud website. Used their web thing that recommends blades for clueless newbies, like me. All of the blades it recommended have positive hook angles, one of the rip blades actually has 20 deg of hook.

    In the books that I have read about radial arm saws, they all say to keep the hook angle as low as possible for a RAS, even negative if available. The reason, they say, is to reduce the forces that cause kickback and saw/blade climb out.

    Should I select blades by looking at the specs for hook angle first, or for application first then select the lowest hook angle, or just go with the Freud web site's recommendation?

    Also, it recommended the same blade design for crosscutting hard & soft wood up to 1.25" thick finish important and for cutting (rip & xc) plywood finish important. But it went with the coated (red) version for plywood, and plain for wood. Could I save a few $$ by using the coated one for both, or would quality of cut somehow suffer?

  • #2
    5 Degree negative hook is a MUST. I am very partial to my Freud 60 tooth crosscut blade. Very nice finished edges. Personally I prefer individual blades for individual purposes. For plywood I would look at one of the specially designed 120 + tooth blades specifically for ply etc.

    [ 04-18-2004, 04:09 PM: Message edited by: G.W. ]
    I came...<br /><br />I saw...<br /><br />I changed the plans.


    • #3
      I second that last post. Neg 5 deg angle. I have a CMT crosscut blade from rockler. Nice bright orange for that exposed blade. For the TS I have a CMT 24T rip blade, Oldham 100T laminate/plywood blade, and Delta Sidekick combination blade for general purpose work.


      • #4
        Do you guys have RASs, and have your blades got negative hook angles?

        For what it is worth, here are the recommendations from Freud's "Which Blade Do I Need" gadget on their web site. All of the hook angles given are in degrees. I looked for individual blades for each type of cutting I plan on doing, i.e. rip, crosscut and plywood. I chose to make the finish quality of the cut most important factor.

        Rippng hard & soft woods up to 1.25", finish important
        tkr206 Hook=15, Teeth=24ATB
        lu87r010 Hook=20, Teeth=24ATB

        Crosscutting hard & soft woods up to 1.25", finish important
        tk806 Hook=15, Teeth=80ATB
        lu74m010 Hook=5, Teeth=80ATB

        Rip & Xc hdwood ply, finish important
        tkr806, Hook=15, Teeth=80ATB
        f810 Hook=2, Teeth=80HiATB

        After I posted the original question here, I emailed Freud and asked them about it. Here is their reply

        First you should read the instruction manual for the saw and follow all the recommendations they make as they are the most knowledgeable about there equipment. Also understand that any information I give you is not to replace or override the info from the saw's manufacturer. So if the manual calls for negative hook then this is what you should use. There are two problems with using higher angle positive hook blades, climbing and lifting of the workpiece. However thin kerf blades reduces these problems while providing a higher quality of cut. If you want the blade that will lift the least then the LU91M010 is your choice.
        The manual for the RS1000 says nothing about blade tooth design. Just says use blade rated to handle at least 3650 rpm, not more than 10" diameter, etc.

        Heck, I don't even remember where I got the idea about the 5deg. negative hook angle. I can't find anything about it in my books on RASs, just to keep the hook angle low. I think one book said 12 or 15 deg or less.

        [ 04-21-2004, 12:12 PM: Message edited by: Scott C. ]


        • #5
          You noticed that Frued stated that thin kerf positive hook blades REDUCE not eliminate the problem. The idea of negative hook blades for SCMS and RAS is an industry recoganized standard. Look at most blade packaging. Most recomend the type of tool it should or should not be used on. I have 35+ years working with a RAS. I still have 8 fingers and 2 thumbs attached to my hands and all in working order. The are a matched set. The only kickback I have had came from my TS. (my own stupidity). I plan on being buried with 8 fingers and 2 thumbs when the time comes. So for me, I'm sticking to what I know. And I know that for my RAS it only gets negative hooked blades.

          [ 04-21-2004, 11:48 PM: Message edited by: G.W. ]
          I came...<br /><br />I saw...<br /><br />I changed the plans.


          • #6
            I used a Freud Ultimate Crosscut blade with a positive hook angle for about a year on my RAS before I purchased a CMT 5 degree negative hook angle blade. What I noticed most was the clean cut and the elimination of the blade wanting to come at me. With the 5 degree negative hook blade I can slowly guide the blade through. With the other blade it wants to come at me and lift up on the material.


            • #7
              Okay, makes sense G.W. and woodypa. Is what I should do to look for blades with a 5 deg negative hook angle first, then go with the highest number of teeth to get the best quality of cut?

              Will look at CMT and others.

              Is there any good, safe rip blade for RASs?

              I've got no table saw. Do have a 26 year old Black & Decker 5 1/4" circular saw. Tiny little thing compared to RASs and table saws, but with a good blade the little booger actually does quite well. Should I plan on using it for ripping and avoid same on RAS if possible?


              • #8
                IMPO there is NO safe rip blade for a RAS. Not that blades are not safe. The RAS is not designed to rip. Yes I know it can and is done, but I personally do not believe in doing so. A RAS is a crosscut, miter saw. Great for dados as you can see your work and lining up a cut is flawless. If it is in your budget, you might look at aquiring a TS. It may seem like an expensive option, but between the two you will have a large range of projects that can be accomplished.

                [ 04-23-2004, 09:22 AM: Message edited by: G.W. ]
                I came...<br /><br />I saw...<br /><br />I changed the plans.


                • #9
                  I agree completely that RAS is not designed for ripping. Don't know history of RAS, but they just look so funny and unnatural when set up for rip cuts.

                  What would be a cool invention is a RAS that allowed the head to be lowered to a position below the table, locked there, and the blade guard to be exchanged for an upper blade guard with TS-like splitter and anti-kick back device. Metal table top that snaps into base would be nice too.

                  Budget is not the problem, space is. I have approx. 14' by 8 1/2' space for shop. It is the inside end of a 22'6" x 22'6" 2-car garage. Minus the 8' X 8' area for the laundry. Minus the space taken up by two of our three cars. I can overhang into the laundry area, like, for example can count that space for the 8+' clearance needed for feeding long pieces into saw for ripping, but can't put anything on the floor in that area.

                  I need to keep at least one workbench in that area for my car work. Have toyed with idea of a single workbench with interchangable top, to keep car crud away from woodworking. Current workbench is 9'2" and 22" wide, but is a car workbench.

                  Also need to keep car tools, in 26" wide roll-away & chest in there, have the RAS that takes up room too, and a 30 ton hydraulic press. Not much room left for TS. Even with wheels, not any space to store it.

                  Since I'm interested in using hand tools for planing and jointing wood, I might as well just use the little circular saw for ripping whan I need to, and finishing it off by hand somehow. True, accuracy of cut will not equal TS (so, cut large, hand plane to size), but is a minor price to pay for actually having room to move around in shop.


                  • #10
                    Scott -
                    Don't under estimate what you can do with a circular saw, router, and a straight edge. Unless you have room for huge feed tables, I believe you can make more accurate cuts with a good CS. I own 2 table saws (lightweight for the truck and TS3650 for the shop) but when its time to slice up sheet goods I go for my circular saw and straightedge. If you need a smooth edge, cut slightly large and clean up with a router.


                    • #11
                      Thanks for the tip about using the router. It is a great idea that I'd never have thought of myself.

                      Over the years that little 5 1/2" inch saw has done very well by me. And, when I take my time with it and work carefully it turns in surprisingly good results. When I got the RAS last fall, I could not bring myself to toss out the little circular. Bought it a new blade instead. Now, with its first carbide blade, it cuts better than ever.

                      Am beginning to see that the key to doing good woodworking is using what you have right and knowing wood.


                      • #12
                        Scott. Sounds like you are cramped for space. If it is possible you might want to look into building the RAS into the workbench area. The workbench becomes the outfeed table and the RAS top becomes workbench.
                        I came...<br /><br />I saw...<br /><br />I changed the plans.


                        • #13
                          I don't believe they are made anymore, but a rip saw would be better than a RAS for ripping.

                          A rip saw is basically a TS setup to perform ripping operations at the expense of the large table top.

                          You can see what they looked like here;

                          Old Woodworking Machines - Rip saws

                          I have seen these listed on eBay and other such site from time to time, don't remember what condition they were in.

                          Does anyone still or in recent history (last 10 years or so) make a rip saw?


                          • #14
                            I just read the many responses and I am beginning to think that maybe I must be doing something wrong. I don't own a table saw, but have owned a RAS for over thirty years and I was taught to use one over forty years ago while still in high school. The reason I like the RAS is that I know where the blade is! When I was forteen I watched my Dad take off a couple of finger on a table saw when the dado blade grabbed the wood he was feeding. Big mistake and dumb things happen, but it left me with a lasting impression.

                            The point is, I've never had the RAS "climb" on me. Nor have I ever suffered a kickback. On crosscuts, I control the feed, not the saw; and on rips, I always adjust the upper guard and kickback pawls, and watch the feed rate. I've stalled the blade a couple of times when getting over zealous on a rip, but that was enough to remind me to be respectful. I've ripped pine, birch, oak, and both ply and chipboard quite succussfully with a standard 10" rip blade. Now I admit that I really am not into cabinet making (yet), but have made quite a few bookcases, a couple of decks, some deck furniture, work tables, benches, and lots of shelving. I've used a variety of blades, but I guess I haven't paid much attention to "tooth angle". So, now that I am retired, and want to tackle some of the finer woodworking arts, I think I need to educate myself a bit better.

                            I like the RAS because for most cuts, the wood is fixed and the saw movement is controlled by me. Rips of course are different, but the saw handles them nicely... just think through the setup and use the safety devices. Overall the RAS is versatile and it doesn't take up a lot of room. Never the less, there are cuts where a TS is the only way to go. Any circular-type saw, takes some thinking and a lot of respect. I too have all my fingers and thumbs and plan to keep them.