unisaw x5 question

could be a “set” in the belts or a loose motor. does it run like this:

http://www.youtube.com/watch?v=a0CGeTLNrCo

note the nickel to the right of the saw blade. that’s how smoothly your saw should run.

also, check that the motor is bolted correctly in the motor mount. the motor hangs on a pin and it’s weight tensions the 3 drive belts. once the weight tensions the belts, there is a bolt that is screwed to the mount that holds the motor’s position. check that all this is properly tensioned and attached, being careful not to force the motor lower than gravity pulls it so as not to over tension the belts.

-- there's a solution to every problem.......you just have to be willing to find it.

Could be the belts have too much slack in them or the pivot on the motor is loose causing the motor to “jerk” on starting.

nope toolie, my saw don’t run like that. MrRon, the motor did jump. I looked at the belts and see multiple problems i think. They definitely look glazed. The center belt seems to have more slack than the other 2, but all 3 seem lose to me. Going to go ahead and replace them while they’re off. Is it necessary to get a matched set?

BTW, forgot to mention, but the jump at start up is more pronounced with a blade on the saw.

-- Gary

I would suggest a match set if possible. I don’t know if link belts work well with this setup or not. Probably something you should research.

-- When you earnestly believe you can compensate for a lack of skill by doubling your efforts, there is no end to what you CAN'T do

You want a set of 3 new matched belts to transmit the load evenly. Check the alignment of the pulleys while you are in there. My UniSaw is 25 years old, only had to replace the belts once!

-- Fine Custom Woodwork since 1978

First off, how old is the saw…? If it’s an X5, it’s prolly about 2008-9…..I have a 2009 X5, and it does the same thing….has done it from the get-go…..it’s nothing to worry about…..Everytime I fire it up, it does a little “quick” jump, and hums like a Singer sewing machine…...it’s a 5 hp, and a beast….it’ll flat eat the wood…no worries, mate…....

-- My grandpa used to say: "Y'all come back when you can....come after dinner, and leave before supper.."

Rick, it’s a ‘06 saw.

How much deflection should the belts have when they’re properly tensioned? Before I removed them, they had about 1/2”. Seemed excessive for such short belts.

-- Gary

I don’t know about the belt deflection….I’ve never had the cowling, or motor cover off…but once the motor kicks, she starts whining, and runs smoooooth…...I guess if it ever throws a belt, I’ll have to take it off, then…...

-- My grandpa used to say: "Y'all come back when you can....come after dinner, and leave before supper.."

Is it necessary to get a matched set?

IMHO, no. the video i posted with the nickel test is with 3 dayton belts, about $5 each from grainger, not a matched set.

How much deflection should the belts have when they’re properly tensioned?

the weight of the motor provides the tensioning force. your OM should have a write up on tensioning.

-- there's a solution to every problem.......you just have to be willing to find it.

On right tilts, You don’t want to support the weight of the motor on the arbor bearings, so just lift a little. Too much it slips, too little it wears bearings. I use factory belts which seem smoother than a set of unmatched grainger belts ( Owwm forums go into this indepth), but its only a slight vibration reduction.

I bought my belts from the saw center who also rebuilt my arbor recently (didn’t want to risk cracking the casting). I second that pulley alignment comment, that was a huge source of vibration for me.

-- --Rob, Seattle, WA

nope toolie, my saw don’t run like that. MrRon, the motor did jump. I looked at the belts and see multiple problems i think. They definitely look glazed. The center belt seems to have more slack than the other 2, but all 3 seem lose to me. Going to go ahead and replace them while they’re off. Is it necessary to get a matched set?.

Matched sets no longer exist. They are no longer made.

I recommend that you use the twist belts from harbor freight.
They work very well and you can adjust the length at will.
In addition they absorb the vibrations.
This what I use on my Unisaw and I am very satisfied with them , like many other LJers are.
I use these belts on most of my tools.
Another advantage is that when a belt is to long you save the extra length and soon you can make a full belt with all the pieces, free of charge.

http://lumberjocks.com/reviews/1770

http://www.harborfreight.com/vibration-free-link-belt-43771.html

-- Bert

Bert, is it as simple as making 3 belts the same length? Or, do you only use one with this type of belt?

-- Gary

Matched sets no longer exist. They are no longer made.

http://www.mikestools.com/49-124-Delta-Replacement-Belts-Matched-Set-of-3.aspx

also, the sawcenter counselled against the use of link belts for unisaws when i posed that question to them during a unisaw refurb. they had a good reason, but it was a while ago and i forgot what it was. i got three UNMATCHED dayton belts from grainger and i think the video speaks to the smoothness of operation and, IMHO, the non-essential nature of matched belts for my (former) unisaw.

-- there's a solution to every problem.......you just have to be willing to find it.

I use the belts from HF and I am very happy with them.
I bought three belts.
I do not if I could have made it with two ,using part of them to make the third one.
Even if you buy three belts and you do not use everything, you will find other uses for what is left.

-- Bert

For matched belts, you have to go to an industrial supply house and find 3 belts that are as close as possible. Each belt has to be measured with a belt measuring gauge and get the cogged V-belt type. This type of belt has a longer life and is more flexible for small diameter pulleys. Link type belts don’t stretch evenly and are not recommended for multi-belt applications.