AboutStuart Mawle Expertise Now been a carpenter & joiner for the past ten years in the UK. I can give avice / help on carpentry & joinery, health & safety, woodworking machinery, power tools and suppliers. I have served an indentured carpentry apprenticeship with a medium sized building contractor doing a wide range of domestic and commercial work. This has included office buildings, barn conversions, building extensions and renovations. During my career, I spent over three years as a wood trades technician at a college. My job involved joinery work, wood maching and helping CITB carpentry & joinery students` pratical projects. I am a member of Institute of Carpenters
I'm a shipwright and just got an older 113.XXXXXXX model craftsman table saw. It has the cast iron top with aluminum trunnions bolted to it with three bolts. I aligned the blade using a dial indicator, and it was precise. However, within a few minutes of use, it was out again. I suspect loose trunnions, but that seems not the case. It will NOT stay in true and has me baffled. Any suggestions?
Additionally, the blade tilt screw is anchored in the flimsy side of the saw, so when I make the tilt, the indicator is no where near correct. When I return to zero, I actually have to go around back and kick the motor hard enough to flex the side back to level to get the blade to true. I do use a digital level box to set my angles, but do you know if reinforcing the angle cranking side is a reasonable idea to stop the flex. I have a decent Delta, but need the portability of this saw for marina work.
ANSWER: I have had to give this some thought....the only thing I can think of is either the blade loses its tension in the cut or there is something wrong on the mechcanical side ie with bearing, belt, belt pulley or motor. Stuart
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QUESTION: Stuart,
Thank you so much for your previous reply. I am hoping I may respond as I have not yet found an appropriate solution.
1.) You considered that the "blade loses its tension" The blade (Freud LU85R010) is anchored to the arbor shaft, and the arbor has just been rebuilt. If it were to lose 'tension', and I presume you mean that it may 'warp', then it would wobble side to side thus creating visible misalignment that changes with blade rotation, and that is not the case. I always check blade for true with a dial indicator before I do the alignment, and I have a 1/2" thick machined steel disk I use for aligning.
The alignment moves by a large amount (nearly 1/16") and becomes steady in that new position. If I realign it, it changes with first use and the change amount is unpredictable.
2.) On the mechanical side, as you know the motor and belt are unlikely to effect alignment as the motor is attached by the dual rod mount and the belt is elastic. If the belt were the cause, as the belt heats (and of course it does), the the misalignment would change because the belt tension becomes altered with heat, but it does not. The misalignment remains fixed even with the belt removed. I rebuilt the arbor with quality bearings, precise shimming, and machining as necessary to make it tight and avoid the typical play in the blade as the arbor moves on it's shaft.
The aluminum trunnions are not the best. I prefere cast iron, but they are not wear marked and fit well (tightly, without play). Each is anchored to the cast iron top by 3 ea. 3/8" bolts. Once aligned, the trunnions should remain so. Something shifts to produce nearly 1/16" of misalignment and I cannot locate the source. I am using a Freud LU85R010 crosscut and working 9 quarters of extremely dense (purple black) Malaysian Keruing (high silica content), so accurate alignment is crucial or it quickly ruins the $100 blade with the heat of the back edge dragging against the cut. In my 35 years as a shipwright, I have never seen anything so frustrating and perplexing. This in truly an enigma. You are a machinery expert, and my last hope.
Also, if you will, could you respond to my concerns about tilt? When the blade is tilted, the side of the case where the tilt screw is anchored, flexes outward as the blade is tilted. This movement has to be stopped or the motor (which swings with tilt) will not return to the original position and I have to go around back and kick it to bring the blade close enough to adjust with a digital inclinometer. I must do this every time I tilt the blade. The only real way I see to stop this involves a lot of difficult bracing including triangulated reinforcing to insure the motion is stopped. This would also possibly mean replacement of the swivel bushing at the crank end. I have visited woodworking sites and read articles about this saw. No one mentions this problem. What do you suggest from your experience with older Craftsman saws? This one is a 1976. I suspect all the Craftsman saws have this problem or Emerson (the builder of this saw for Sears) developed a fix and I do not have it. Can you please use your expertize to assist me in this before I must solve it in an inappropriate and time consuming manner?
Thanks again for sharing your time and extensive expert woodworking machinery knowledge.
ANSWER: To be honest, it hard to understand what going on from a far, however the type of blade, type of timber being cut, and the machine all factors in this....no one thing could be overall responsible.
If the blade had over heated then it could lose tension in it self and not be able to cut accurate during future cuts...you cant tell this by dti gauge. Once tension is lost then it can not be restored unless a saw doctor takes a look at it...somehow I wouldnt have thought this size blade would have lost tension.
I never bother with dti guage so I just set my up with engineering square making sure that blade is 90 degrees to the table. I never bother with tilt degrees, alway set my blade angles with templates or got one of them digital boxes but realign it to 90 degrees with the square. I dont like the sound of you kicking it(force) back into position as this could be factor.
I dont want you to take this the wrong way....but to me this type of saw is like a toy compared to the machines I use, understand your need for portablilty and there is cost involve but you have to weigh it up against your time, and if you need to be accurate then perhaps the machine as had its day and look for a better option. I wish I had a better answer for you. Stuart
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QUESTION: Thank you for your time, I sincerely appreciate your assistance and apologize for the length of my replies, but they must be as provided to assure clarity without to sever possibilities of misinterpretation.
Would you please tell me what you mean by " loss of tension" in the blade. Is that what some call "temper", or a loss of hardness uniformity throughout the metal? I have seen that cause the blade to distort and "wobble" irregularly depending on the heat produced by the feed rate. I am professional enough to set the carbide teeth a distance above the stock for quick material release, blade cooling, and to help prevent burning on some woods. I know feed rates and am not aggressive, preferring a smooth hand-planed look to the cut. I can assure you that in my case, "tension" is not the culprit.
Nearly any saw in the right hands is capable of accuracy--even what you refer to as "toy" saws. I'm sure many Craftsman saw owners will be riled by your comment, calling what they cherish and perform creative and excellent work with, but I am not. For many years I used one of those little Craftsman aluminum table top saws as my mobile device and it was perfectly accurate providing I assure the setup before each cut. If my cast iron Craftsman is a "toy" perhaps to be laughed at by the real professionals like yourself, that aluminum saw I used would probably be called a 'Gag gift", Christmas stocking stuffer, disposable joke saw, or the like. We buy larger, more expensive saws for production capabilities, speed ease of use, accessories, weight, to follow the crowd, etc, etc. not because smaller "toy" saws are not capable of accuracy. Many people don't realize that the little saws can be accurate. Even hand saws can prove extremely accurate. Some of the work I did in 70 to 134 foot custom, multi-million dollar all teak yachts was with that "toy" aluminum saw, hand saws, files and rasps, saber saws, and carving blades. I will not place a fit piece until the joint is within my very rigid specs, and my "toy" saw got me there with consistency, but perhaps not speed, as setup takes much longer. I have been tipped as much as a thousand dollars for my work with my "toy".
When I say "Kick" to straighten the saw, I don't mean with my foot. I kicked the motor back into position by pushing it against the stop--using my hand. Kick is Oregon jargon for "move". My apologies.
I dislike questioning an expert in woodworking machinery, but I cannot see how the blade or the wood being worked can be a factor in blade alignment. Could you please offer myself and the many other readers your expertise and explain this phenomenon in a little more depth? The blade spins on an axis as determined by the arbor and will remain true as long as the arbor mechanism is tight, true, without excessive side play, and unable to shift unexpectedly. The trunnions must also be tight, and they are. so how does blade tension effect alignment? Or are you meaning the blade wobbles and that perhaps I mistook that for actual alignment?
I had a thought as I was writing this and took another look at the trunnions. As I said previously, I am more use to cast or steel trunnions having never had aluminum trunnions before, a much softer, lighter metal. As I wrote about tight trunnions I saw the lock washers under the bolt heads in my mental picture. They are the star type of lock washers with multiple bent "blades" and I know these can damage soft aluminum--especially with repeat use at the same location. I went to check and that is the case. It is also the cause of the problem. This is an Eureka moment, for I have finally solved the puzzle. The lock washers have created it!
The star type lock washers installed on the trunnion retaining bolts on these saws (and shown in the manual) should not be used against aluminum when there is the possibility of repeated tightening. Blue locktite is preferable as the lockwashers, over time, will dig into the aluminum causing damage to the surface. I removed the trunnions and inspected the area in contact with the retaining bolts. It had become "dished" or concave from the effect of repeated tightening. The washer teeth will dig in when the bolt is tightened. This has produced a sort of "automatic centering" as the head of the bolt with the star washer in place, would slip downhill to rest comfortably centered in this depression. That was why the bolts, even though aligned and tightened, moved when the blade was adjusted. Additionally, I found that repeated aligning and bolt tightening over the years had reformed the aluminum to push it into the 3/8" oblong holes, reducing the available movement of the trunnion for alignment.
I will have to resurface the area of bolt contact to produce a true "flat" and file the unwanted material out of the oblong alignment holes so the original room to shift the trunnions is restored. I am sure that will eliminate the problem with changing alignment that I was experiencing.
I checked the Craftsman manual for my saw online and found that this star type washer was indeed specified by the Emerson engineers when this saw was designed. The Emerson company built this model Craftsman saw for Sears.
So, thank you again for your assistance. Perhaps you could not necessarily solve this or know what it was, but by writing to you, the problem was uncovered. Now both of us knows something new about the very popular older Craftsman saws that so many home and professional woodworkers use and love Maybe it isn't such a "toy" after all. This has been an excellent gain all the way around. Now I am sure I can achieve the consistent accuracy I needed within a lightweight contractors saw.
I was hoping you could recommend something about the side of the case flexing and not allowing the blade to return to vertical, but perhaps you are very busy or just unconcerned with the trivial. I'm sure you "experts" in this field are in constant demand and you have little time for those of us with minor difficulties that we should know how to fix ourselves. So I do thank you and I feel better now that one problem is fixed, and I will attempt to find someone less in demand who can help me with their knowledge of these popular contractors saws.
There is a teenager in our neighborhood who I hear has one of these Craftsman "toy" saws and is extremely well versed in solving the difficulties. Perhaps he can help me fix the problem with the flexing side.
All in all this has been a very successful day for me and I sincerely thank you for all your valuable time and your complete expertise in saw mechanisms. Perhaps in time I will be better versed myself and I can be an "expert" too. I sincerely thank you again, Sir. You have a very fine day.
Answer I like to help out where I can...glad that you were able to solve the problem yourself.
I have never had or owned a craftman saw or similar machine and with the written word,...well, there is no better way of seeing the machine and the problem for yourself in front of you. Felt that there could be one or more things going on. If you use the kit, industrial machines then you would understand there is a hugh difference, as I am sure your equipment does everything you want it to do.
My knowledge is general when it comes to machine repairs as it would be like taking your jeep to a ford dealership and saying can you fix this...and to a degree they should be able to, but it wouldnt be as good as some one who is a mechanic that works on jeep everyday, knows them inside and out.
I am really a wood machinist, not an engineer using woodworking machines to effeciently, safety and produce quality par/profile sections and joints so it more about knowlege of different blades, cutters, setups, speeds, feedrates, jig work and more importantly timber lore, ie how it cuts depending upon type of grain, dealing with cups, bows and case hardening.
Talk of which, saw blade arnt just metal discs, with teeth on; some have stabilizer vents for reduced vibration. Durable microGrain titanium carbide teeth for durability, and substain a prolong cutting edge. They all have heat expansion slots allow blades to expand and contract during use keeping the cut true and straight with precision tensioning keeping blade flat & true during use. Heat may effect the blade/cutting during prolong use but If the saw blades overheats as I understand it will lose this tensioning, once the tensioning has been lost then it has to be put back. You cant see or tell if the tenion has been lost, but you start cutting then and you know it isnt cutting true, minute wobble effect can be seen looking at the saw cut. The people that can do this work is a saw doctor..for better way of describing it is like watching some hit the saw blade with a hammer...it's not that simple, as they hammering it in a special way. I have 2 or 3 blade types depending upon what I am doing...most of mine come with some coating, teflon/ptfe but I still ensure that I have clean teeth, apply thin paste wax to the blade (whilst machine is off, power disconnected) and to bed of the table saw, most of the time it done at the end of the day. I think it important to do everything possible to ensure a1 results and clean cuts.
I like to think that I am humble enough to say I dont have all the answers, always listen to other people views, idea, an opinions...they are always more than one way to skin a cat likewise I am open to ideas, new methods and processes...should anyone in the future experience similar will hopefully see this Q&A will help, especially since you found the solution yourself. Stuart
