Miter saw runout

[cptn_zippy]

Bought a new sliding compound miter saw today... A 12" sliding compound miter saw (Hitachi C12RSH2) and have a question about the runout of wobble of the blade. It looks a bit excessive, I'm measuring about .012-.015 of an inch - does this seem normal? The new one is belt driven, my old saw has about .003 runout, but it is direct drive. I've played around with cleaning the arbor, washers, and tried a different blade, repositioning it, etc...but the runout has stayed pretty constant.

J

 

[Bigblockyeti]

That seems a bit high to me. I measure between .002" & .004" on my 10" Ridgid depending on what blade I have installed.

 

[larry_g]

How and where are you measuring runout? What is the runout when measured at the arbor? Also are you talking lateral or radial runout? Are you measuring the same on a varity of blades?

For me to test something like this I have to start with the arbor and measure it first. Confirming it straight or the problem. Then move out measuring each additional item added to the arbor.

Keith Fenner did a real good series on tuning up a grinder and many of the measuring and problems he found could be applicable to your saw.

It is a 3 part series so watch all.

lg
no neat sig line

 

[cptn_zippy]

Lateral runout. I took apart the gearbox assembly, cleaned and reassembled, with even tightness of screws and now I'm down to 8-9 thou. Using a dial indicator bolted to a metal block clamped to the fence. I'm measuring about an inch or so from the teeth, with the slide and chop motions locked.

J

 

[larry_g]

So what are you measuring for runout at the arbor without the blade on the machine?

Mark the blade at the high spot, then loosen the arbor nut and rotate the blade 180* in relationship to the arbor and measure again. Does the high spot follow the blade or the arbor? Or said another way, is the high spot still at the mark on the blade or 180* out from it? This will help determine if the blade is the problem or the arbor.

You have to take a systematic approch to your measurements, mark and move components around in relationship to others to figure out just where the wobble is generated.

Do you have another blade to check with, to eliminate a bent blade?

lg
no neat sig line

 

[cptn_zippy]

Thanks for all the measurement tips...watched a video, marked the blade, etc...measuring the arbor is pretty difficult based on the size, location and my lack of equipment. As I noted in my initial post, have tried two blades, runout is virtually the same. However....My question really is what is an acceptable amount of run out in a belt driven miter saw, as compared to direct drive, and 10 vs 12 inches of blade diameter. More moving parts is likely to increase the likelihood of runout. Willing to accept that some exists...I guess I was hoping that people would respond with some of their experience.

Thanks

J

 

[Milton Shaw]

That runout will not really cause a problem other than the saw kerf is going to be wider than it should be. If the blade tracks true on the slides and pivots, the saw should function all right. Yes it would be nice if it was truer but it really won't cause a problem. It will help keep the blade from burning wood from being to tight in the cut. In a perfect world it would be true, decide if it means enough to return the saw and start over.