This article was originally posted to my website, www.woodshopmike.com. Be sure to stop by my site for more DIYs, repairs, and projects & remember to subscribe! Now on with this Instructable!
When you get past all the bells and whistles of some modern table saws, the machine is really quite simple. There's an arbor that spins a blade... But even with a great fence, miter gauge, and whatever other accessories you pimp out your table saw with, unless the arbor and flange run true, you're going to experience reduced accuracy and cutting power. Soooo, how 'bout I show you how to improve or completely eliminate the run-out of your table saw? Cool...let's dig in!
For this process, you need a few items:
- Tablesaw :)
- Dial or test indicator on stand to measure run-out
- Miter gauge
- Scrap mdf, plywood, etc. about 4" x 12" & 3/4" or thicker
- Sharpening stone (I used an old two sided oil stone)
- 2 clamps, I used Irwin quick grips, but a similar clamp will be fine
- Small flat edge, must be accurate
- Safety glass or a face shield is a must. In fact, just go ahead and put them on while you read the article :)
Step 1: Checking for Run-Out
First off, you'll want to confirm that your blade does indeed have run-out. To check for gross run-out, turn the saw on and then off. While the blade is slowing down, watch the outer edge for side to side movement. If you can easily see this movement, you're looking at a minimum of .010" run-out at the edge of the blade.
This means one of two things. Either the blade you're using is warped or the flange on your table saw's arbor needs to be trued up. By all means, put on a high quality blade and recheck if possible! If you don't have a good quality blade (usually $60 and up) then you'll have to go straight to checking the arbor's flange for run-out.
Just a quick aside, in my opinion, if you can't see the blade moving side to side while it's slowing down, then you probably don't need to bother tuning anything up. But feel free to forge onward if you're like me and just gotta have everything perfect... It's a sickness really :)
Anyways, next you'll need to unplug your table saw! No one wants an oopscident while working. Check the flange on your table saw for run-out with a dial indicator. If you say, "Gee Mike, what's the flange?", I'd tell you it's the flat part on the arbor that the blade is pressed against when you tighten down the arbor nut. If you then ask what the arbor is... well... :)
Moving right along, set up the dial indicator to measure the flange. Setting up the needle as perpendicular to the flange as possible will make things a bit more accurate, but don't sweat it too much. This is a table saw after all, not machining equipment. For me, if the flange run-out is .002" or less, just go buy a good blade and be on your merry way. Otherwise you're getting ready to have some fun!
Step 2: Set Up Stone
During the process of grinding the flange, you'll most likely create some sparks. Soooo, unless you want to risk a fire ("I hate fire"....any other "O Brother, Where Art Thou fans with me on that one?) in your table saw then do yourself the favor of cleaning out the dust real quick. Not spotless, lets just mainly get the hamster bedding out of there :)
Remember that piece of scrap MDF? Grab your miter gauge and attach the MDF to it so that you can clamp your sharpening stone in the proper area. Check out the photos below to see what we're after. The first picture is from the front of the saw and the second one is there to just help you visualize what all is going on in this setup.
Got it? Good. Before we go further, I should mention that it's a good idea to make sure the end of your stone is flat lest you grind a funky pattern in the flange.
Now, how the heck do you know what all the angles should be? Set the table saw to around 45° and then clamp the stone loosely in place. What you want to end up with is the outer edge of the flange to be slightly higher than the inner surface of the flange. This will help the blade to be more stable. Think about what would happen when you set a cup down if the bottom was convex instead of concave...darn you spilled your coffee, no good. With light pressure, arrange the stone as I just described and clamp it securely in place. Just for a dummy check, pull the miter gauge towards you and make sure there isn't tons of resistance against the flange. Then slide it back in place and turn the arbor by hand. You should see just the slightest amount of scratch marks appear on the flange. You can also tell if the stone is angled correctly based on where the scratch pattern is. There should be more scratches towards the inside and less or lighter scratches towards the outside. If yours looks like the photo below, then you're good to go.
Step 3: Time to Grind! Good Luck!
So, once again, pull the miter gauge forward, removing the stone from contacting the flange. Plug in the saw and turn it on. Slowly advance the stone against the arbor and watch the sparks fly. Ohhh pretty. Alright, don't get carried away. Once the sparks decrease, switch off the table saw and wait for it to stop before moving the stone. Once stopped, pick the miter gauge up out of the miter gauge slot as to not further scratch the flange. You may have to repeat this process more than once depending on how bad the run-out is on your saw. Once the flange looks like the photo below, you're ready to measure again!
Step 4: Check the Flange
Remember that little straight edge I mentioned? Now it's time to put that thing to work. Lay the straight edge across the flange to ensure that it's flat. If the straight edge rocks back and forth or there is space under it at the edges, then you have a high spot in the middle and need to re-grind the flange. Otherwise, you're good to move on!
Set up the dial indicator again and this time be sure that the needle rides just inside the outer edge and see what the run-out is.
If you measure .002" or less then my friend, you're just about done. If you measure more than .002" then make a judgement call.
If you can see areas that didn't get ground on the last pass, take a little more material off. Dents in the flange won't impact the run-out of the blade as long as there's not raised metal around the dent.
The reality is, there's flex in the assemblies that hold the arbor and flange in place so you'll rarely get a table saw (unless it's an old Oliver, Tannewitz or expensive industrial tool) that will not move at all when force is applied to it. But regardless, you've certainly improved the accuracy of your saw.
So, now it's time to put on a blade and make a test cut! If everything went according to plan, you shouldn't see anything but a beautifully smooth surface ready to glue up.
Thanks for reading! If you have any questions please don't hesitate to ask. Drop questions or comments below or feel free to send an email. Also, be sure to subscribe so you never miss a post or giveaway!
Have a great day y'all!