radial arm saw has 20 thousandths of wobble in the blade

[cody michael]

I have a new to me craftsman 12 inch radial arms saw. I bought a new for it, and the cut has a bunch of saw marks. I got out my dial indicator and it measures about 20 thousandths (my table saw saw setup measures 1-3) I cleaned up arbor put blade back on same thing. Tried old blade. Same thing. Any ideas?

[Myk Rian]

Is there runout with the arbor flange? If so, you'll have to get that trued up.

[cody michael]

HHow do I check that? If there is how do I fix it?

[HANK METZ]

HHow do I check that? If there is how do I fix it?

Google is still your best friend Cody:
https://www.google.com/search?q=how+to+check+for+runout+with+the+arbor+fl ange&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=nts

[cody michael]

if there is wobble is this an except able method of fixing it? what type of stone would I need? I don't have any.

http://woodgears.ca/saw_arbor/

is something like this what I would need? any better inexpensive solution? if a very basic stone that could also be used to sharpen hand planes would work can someone link it. I have a few but only times I used them I sharpened on my grind I use for lathe tools, so there is lots of room for improvement.
http://www.amazon.com/Bora-501057-Combination-Sharpening-Aluminum/dp/B003Y3BMAW/ref=sr_1_3?ie=UTF8&qid=1416487948&sr=8-3&keywords=grinding+stone

[cody michael]

Would the grinding stone help to fix this issue?

[Duane Meadows]

Possibly. As Mathias states, it needs to be held stable with respect to the arbor.. can't do it hand held( on the arbor with the motor running anyway)! Also keep in mind that a very small wobble(runout) at the arbor washer will create a much larger wobble at the blade tip!

Also If I remember correctly, the arbor washer is removable on that saw(is on mine anyway) so flattening off the saw is likely the best way to go.

It's also worthwhile to check the arbor shaft(motor shaft) runout as well. In fact i'd want to do that first... no point trying to flatten a washer and finding out the motor bearings are bad or the shaft is bent!

[cody michael]

My arbor has a spacer on each side of the blade, so I don't know how to check that for run out? The spacer just moves?

[Don Jarvie]

Check the arbor the same way you checked the blade. Put the indicator on the arbor washer and spin the arbor slowly. If its out it will move the indicator. Mark the high points and file them so the arbor washer is flat all around. Then do the outside washer.

You said you were using am old blade. Put a new one on and see if that is the problem first. The blade may be warped. It doesn't need to be a 12 inch blade just a good one. If its the blade get a new one.

[cody michael]

I put a new blade on, that is when I examined the cut, and noticed the issue. I put the old blade back on to make sure it wasn't the new blade, same issue with old one.

The arbor washer is very loose if I touch it it can spin freely, so I'm not sure how to measure it unless I made some sort of spacer to hold it In place, not sure how to do that accurately though..

[Ronald Blue]

It looks like you would only need a couple flat washers so you could run the nut down and hold the arbor washer secure for checking run out. While there put your indicator on the hex that the arbor washer rests against. The indicator should barely wiggle or it will multiply the further you get from the center line of the shaft. What does the other washer look like? I question if that is the original or correct washer. Usually the washer or blade support is hollowed out on the blade side so contact is made only at the surface at the arbor and again at the outside of the washer. The other side usually is beveled off on the outer diameter. That just looks like a flat washer. A stamped flat washer isn't going to be flat and even a couple thousandths distortion will cause blade unacceptable run out. Good luck.

[HANK METZ]

If the inner faces look clean, examine the outer, working edges. They may be galled or have metal upsets that prevent them from seating properly. I'd simply stone inside and out surfaces ever so slightly, reassemble, check again for deviation, it may be all it takes.

[cody michael]

I do not know if they are the original ones but they are not flat, the inner portion is recessed and the only part that touches the blade is about 1/4 in from the outer edge.

I cleaned up before arbor washer before I reassembled last night and it didn't make any difference.

I am not sure how to put the indicator on the where to washer hits, it is pretty small, the lip i could use is smaller then the tip of my indicator.

[cody michael]

I have a grinding stone I picked up today, any ideas on how to keep the arbor washer held in place accurately while i grind it?

[Myk Rian]

I have a grinding stone I picked up today, any ideas on how to keep the arbor washer held in place accurately while i grind it?
Read Ronalds post a few up.^^^^^

[Duane Meadows]

One other thought... the outside blade washer should be the same diameter as the inside one. If not, or if you don't have the outside washer, tightening the nut can really distort the blade! Just a thought.

[cody michael]

There is an outside washer. It's just not in the picture, they are the same size

[Duane Meadows]

Cody, what's the model of that saw? Did you try exchanging them?

[Rick Potter]

The washer in your pic looks like a stabilizer accessory to me, Cody. Check the online manuals for your saw, and see it that is what the arbor washer is supposed to look like.

Is it steel?

Rick P

[Mike Null]

I have two ideas, neither of which may be relevant. 1. Is the motor/blade exactly perpendicular to the table and is it exactly perpendicular to the fence? 2. Try a 4" blade stabilizer.

[Myk Rian]

I can see this whole thing going south.
Cody, find someone that knows machinery to help and advise you.

[David Eisenhauer]

As Duane said, did you check to see if the wobble you have exists in the motor shaft? This needs to be done first before you chase a problem that is not the real problem. If the arbor is OK, then you will either have to try and flatten out the flange washer on the saw or off the saw. Without being there, it would seem to me that removing the arbor flange from the saw and spinning it down against a stone would be easier (paint the surface with Marks-A-Lot to check on progress). Or, use some spacer washers and a nut to hold the flange tight against the arbor for truing in that fashion. You may have to grind down some washers and another nut to expose enough of the outer rim of the flange washer to push the stone against. At some point, you will need to try something.

[Duane Meadows]

Put a mark on the arbor, and a mark on the washer. Turn the washer 1/8th of a turn reinstall blade and recheck the runout. Do this for a full turn. If it follows the washer, the washer is the issue. If it stays in the same position relative to the arbor, then the arbor/arbor bearing surface is the issue.

Being that the washer is removable, flattening it off the saw would be much easier. Both surfaces of the washer need to be parallel(perpendicular to the arbor hole as well!). Work carefully! It will likely require removing only a very few thousandths of an inch from the high side. Marking as above will help in determining the where that high spot is!

On my saw the inner and outer are very similar, if not indentical. Thus I would reverse them and check the runout again. If it decreases, pretty good indication the inner washer is at fault!

Myk, it really ain't rocket science! I spent 30+ years as a tech for Sears. Have worked on many a RAS over the years.


Also, though very important, blade alignment to the table, the arm, or anything else will not cause blade runout. It will of course cause quality of cut issues!

[Paul M Miller]

Is the hex spacer loose on the shaft. or fixed? Before I did any grinding, I would assemble the blade, washer, and spacer on the shaft, then make a mark on all three so that alignment can be duplicated. Check the runout and mark the outside of the blade at it's highest point. Then alternately rotate each of the 3 components 180*, checking runout with each configuration. This should tell you which component is out of whack. Long story short, if you grind away on the washer and it was the spacer or blade that was bad, you'll have the same problem unless all the components are aligned the same every time you put the blade on.

Come to think about it, I would add the shaft to the list, making it 4 components as variables.

Paul

[cody michael]

I worked on it today, got it down to 8 thousandths wobble then ran out of time will try for better tomorrow, what is acceptable for this?

[HANK METZ]

I worked on it today, got it down to 8 thousandths wobble then ran out of time will try for better tomorrow, what is acceptable for this?

That is a personal preference, anywheres from 0.0" to .008", depends on what you deem acceptable- the real test is to make a shallow kerf in scrap, compare it to the blades' tooth width. Good work though, once you took the plunge it wasn't all that bad now was it?

[cody michael]

It took a little while to figure out good technique but is going ok, my biggest issue is there are still saw marks on my endgrain.

[Don Jarvie]

Have you gotten a copy of the manual and set the saw up?

[cody michael]

I really need help, I have spent 5ol or 6 hours working on this over the weekend. At one point I had it down to 8 thousandths but I still was happy with the cut, I tried to get it closer and made it worse, it is now about 25 thousandths, of wobble. I really like this saws setup.

Can someone please let me know if there is something else to try or if I can get a new arbor? Or do I just need to look for a new saw? The blade on start up wobbles enough you can see it. I am somewhat mechanically handy but have never had an issue like this


I think part of the problem is the inner arbor washer isn't fixed in place, it just hits a small nut shaped spot. I think if that is off a hair or the back of the arbor is off then when it spins it throws everything off. Otherwise I don't understand how grinding it down doesn't fix it. I start with the grinding stone just hitting the high points let it run for awhile. Tap it a little closer let it run do that a few times then when it seems to not have high points I check it with dial indicator. I haven't been able to get the arbor washer to have better then 2 thousandths run out. I'm very frustrated

[john lawson]

post some good close up pictures of the arbor and the washer and nut

[cody michael]

Ok I will post some pics tomorrow.


I missed a few of the posts above. I will try rotate the washer to see if the wobble moves with it