14" Rikon bandsaw...slight table vibrations

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Truefire

New User
Chris
I had an incident on my 14" Rikon bandsaw a couple of weeks ago. I had a 4 TPI blade that possessed aggressive teeth installed for cutting larger logs in the rough. During that time frame that particular blade was installed, I attempted to take a short cut and use that blade to cut a segmented glue up consisting of various densities. About 1/3 into the cut, a tooth grabbed and the entire operation slammed to a halt, literally. I struck the off button as fast as I could reach it so as to not burn my belt.

Well, ever since then running my 10 TPI blade again, the table will vibrate ever so slightly periodically during operation. Approximately 30-45 seconds after the machine is turned on the table will vibrate just enough to shake my hand, like I have the tremors, if resting my hands on the table. It will not do this immediately after motor and blade has reached full rpms, which on this saw has always been almost immediately. It takes a little while before the vibration will start to occur. Like it has to build up its frequency as its resonating through the machine.

I took both wheels off and checked my shafts for disruption, neither look like they were damaged or bent. The pair of bearings in both wheels are intact and installed tightly with no play. I checked the tires very well for some slight bump that could have been created during the incident, all seemed as smooth as they always have. I ran the motor pulleys without the belt installed, its so smooth you could not tell it was running. I ran the lower wheel with the belt installed but without the blade in place - the lower wheel ran really smooth with no apparent bounce or otherwise.

Of course, I could not figure out a safe way to run the upper wheel without installing the blade. But after everything was buttoned up, the saw still has the before-mentioned vibration. Not quite sure how to pinpoint where its originating from. The blade itself is a 10 TPI 3/8" blade and the weld is really smooth and the entire run appears to be without any imperfections or kinks.

Just strange. I never had this issue until my incident.

Apparently something was damaged but it is so superficial, I cannot without engineering equipment, locate it.

Any thoughts?

Oh yeah, let me throw this out there--> It cuts just as straight as it always has, very straight...no issues in that arena, its just the slight vibration emanating from the table is just ANNOYING a perfectionist such as I!!!!
 

McRabbet

Rob
Corporate Member
You may have created a "flat" spot on the drive belt(s) which may be causing the problem. Worth checking the belt and replace if necessary.
 

JohnW

New User
John
Once the vibration starts...does it continue, or come and go? If it comes and goes, it's probably a harmonic vibration caused by some slight imbalance in something that rotates. Your motor, drive pully, drive belt, tires or blade. If to continues to vibrate constantly, it would more likely be a larger inbalance in one or all of the above...or something bent or loose.

Also, did you try moving the saw to a different spot on the floor and/or making sure it's feet, wheels or base is solidly planted on the floor? Sometime, just a very small shim at the base can stop a vibration.

Also, check you 90 degree stop under the table. Could be you have your table tightened down to about 90* but the sudden stop moved your stop just a hair and it's vibrating against the bottom of the table. I'd loosen the table and re-set to make sure it's not touching the stop and then see if you vibrate.
 

jglord

New User
John
One other thing you might consider is calling Rikon. I have called them several times for various customers and they have always been very helpful. If replacement parts are needed, they get them out to you very quickly.
You seem to be covering all the bases but maybe there is something they can suggest.
 

Truefire

New User
Chris
I have checked the table and although confirmed it is not loose, I have not loosened it altogether then moved it out of 90* and reset. I need to move and reset.

The vibrations come and go that's what puzzling. It is as if two things are resonating at different frequencies and the colliding soundwaves are creating the vibrations. That to me, is seemingly why it takes about 30-45 seconds for this to build up and begin showing up. A couple of times the table has shaken really bad when I turn the saw off then the other 85% of 'turn offs', it doesn't. During operation, it will come and go periodically, ranging from the table sitting perfectly still to other times shaking my hands as if I have very mild case of the tremors, when resting my hands on the table.

You know, I called myself checking the belt and knew to look for a flat spot...that was one of the reasons I had turned the motor off as quickly as I could possibly do so when the incident occurred because I did not want to create a flat spot on the belt. In the midst of the breakdown last night however, I was so concerned with checking the shafts and wheel tires, I never did even check the daggone belt for a flat spot. Dumb me! "Where was I?"

As far as the saw's footing and foundation- I have looked at the base really well to ensure the rubber feet had not slid, it seems really solid and all of the bolts and nuts are still tight. There are no known gaps between the rubber feet and the flooring and the base to saw juncture is tight and still like its always been. I had thought about the location in which it sits as being part of the issue perhaps but it has been sitting in this location for awhile and not giving me any issues until after this incident.

I am certainly going to assess the belt in just a moment. I plan on just replacing it so that I can cross off my inputs as I go.

We shall see....

I had initially thought it was the dust which collects inside the rear portion of the drive wheel hub. A good thorough cleaning and vacuum ruled that out.

Whatever it is has to be superficial and is amplified by the rpms thus making me wonder if I will be able to assess without proper equipment. I may just end up switching the wheel tires
 

ehpoole

Administrator
Ethan
Chris,

The belt is certainly one of the first things to be checked -- don't feel bad as we all get caught up in the moment from time to time and overlook such things when we get flustered! When I first got my 18" Rikon I had a vibration issue I quickly tracked down to the belt so I replaced my belt with a link belt and have had very good results. More expensive than a new V-belt, but much less vibration prone.

If you eliminate the belt -- or better still just replace it on spec -- then the next step is to run the bandsaw with no blade installed and see if any vibration occurs over the course of several minutes.

Then try a couple different blades, ideally a wide and a narrow blade (e.g. a 1/8 to 1/4" and a 3/4" to 1"), and see if there is any change in vibration.

If you notice more vibration with the narrow blade, this is usually a sign that the blade is wandering a bit as it constantly hunts for the wheel crown, especially under lighter tension. This is not uncommon for bandsaws with lightly crowned wheels when using narrow blades (Note: I am unfamiliar with the crown characteristics of the 14" Rikon) and it tends to improve with an increase of tension and adjustment of the tracking to better center the blade on what crown there is. This can often be seen as a slight wobble in the upper wheel as well as the hunting behavior of the blade. Most upper wheels have a little free play in them due to the tensioning and tracking mechanisms and this is usually exacerbated at lower tensioning levels and, especially, with narrow blades which offer little lateral stiffness to resist this motion.

If you notice the same, or more, vibration with the wide blade then tracking and hunting are much less likely to be the cause as such blades are usually stiff enough to resist those forces. Then you need to inspect the tires for any damage or flat spots and, if need be, measure the runout on each (upper and lower) wheel and/or tire. If the runout seems excessive then unmount the wheels to measure shaft runout as well to ensure the shafts did not bend under the load. If necessary, replace the shafts or tires as appropriate.

If the 14" Rikon is constructed similarly to my 18" then it may also be helpful to know that the lower wheel can be moved in or out and its angle adjusted so that it is coplanar with the upper wheel. It is possible that the factory adjustment may have been altered by the Event, in which case the wheels would need to be readjusted for coplanarity.

Also, inspect the bandsaw thoroughly for any pieces that rattle and can induce their own vibrations to add to the harmonics. On my bandsaw, I modified the belt tensioning adjuster assembly to remove a major source of vibration and rattling. If you find a rattle, try to restrain it momentarily (use your hand, duct tape, whatever works and is safe) to stop the rattling and see if your bandsaw's vibration characteristics are suddenly altered-- if so then address the rattle more permanently.

Also, for thoroughness, be aware that paranoia after an event sometimes makes us keenly aware of minor issues that may have always been considered normal in the past causing them to suddenly seem like a new behavior. Not saying that is what is happening, but it is human nature and something to consider once all else is ruled out if no major issues are found. BTDT.

Most of all, best of luck in your quest! :)

PS -- I almost forgot that you are mentioning table vibration as well. While all of the above will also cause general vibration which will be most noticeable in the table as the table tends to amplify vibration, it is also possible that something is loose or broken in the table or trunnion assemblies themselves. Inspect the table thoroughly, perhaps even breaking things down a bit so that you can better inspect the trunnion assembly. Make sure all the bolts are still tight and that nothing has cracked in the assembly or castings, then reassemble everything when you are confident all is as it should be.
 

Mark Gottesman

New User
Mark
I can't add anything to Ethan's thorough reply for troubleshooting except the following. You can find a reasonable replica of the red link belts at Harbor Freight for about 1/2 the price (use the coupons). It is green and I have used it on both drill presses and table saws with good results. If the motor pulley and driven pulley on saw are cast pot metal see about replacing them with machined cast iron. They run a lot truer.

Good luck with tracking down the vibration.
 

Truefire

New User
Chris
You know, although I know my saw has not done this before, I totally agree with you Ethan regarding human nature and how 'read into' things. It may very well have always had some level of minute vibration but I know it hasn't ever been this bad. It really isn't too severe now, its just annoying. It cuts fine and maintains a straight line as always. Its just that a table of any type of equipment, is just 'not supposed to do this'....!!

I am thinking the incident threw the bottom wheel out of coplanar from the upper wheel. Although there exists a way to adjust the lower wheel shaft, how in the world would anyone be able to execute such a feat in a common woodworking shop apart from technical engineering data collection devices? I mean seriously!

The manufacture did not implement any means of measuring movement into this lower wheel. One has no idea 'where in the plane' the lower wheel is, in regards to the upper wheel, if any adjustment is attempted. The lower wheel shaft just protrudes through the rear housing of the machine and is held 'in alignment' by four machine bolts arranged at 90* intervals around this shaft. Its the most ridiculous setup I have ever seen. But, I have never had any reason to manipulate the original setup before so I have never adjusted those machine bolts.

Honestly, its pitiful engineering in that regards; my housing is practically bullet proof (made and welded very well) but then Rikon just sticks an axle through a hole and aligns it with four 'cheesey' machine bolts. :icon_scra Must have been -- 'get off early Friday-heading to the beach day' for Mr Engineer and his party. Who knows?

At any rate, I believe this might be where the issue lies. There was enough energy dispersal when the incident occurred that it could have very well caused shifting in those small bolts or caused one of the four to dig into the shaft a touch thus shifting the shaft, ever so slightly. The shaft would not have had to move much, I would not think, for those wheels to run out of coplanarity. I just keep thinking this is where my issue lies.

--
As far as the wheels are concerned Mark, yeah they are that cheap cast stuff that most stuff of today is composed of. I would love to buy me a set of machined wheels. Great investment it would be. You have any good sources that you would recommend?

Thanks
 

ehpoole

Administrator
Ethan
FWIW, the four bolts working in a push-pull arrangement against a fixed fulcrum is a rather time honored approach to tweaking such in lieu of considerable more complex alternatives. If you celebrate Christmas each year with a Christmas tree then you may even recognize the configuration as being identical to that employed in many tree stands for securing and centering the tree.

You can check for coplanarity in the shop with a bit of ingenuity. Most modern bandsaws are built in very much the same manner as your Rikon with the wheels recessed in their safety housing.

First rule to keep in mind: Coplanarity should be measured with the bandsaw under typical tensioning levels as the bandsaw's frame will flex a bit under tension. If you often use a mix of narrow (low tension) and wide (high tension) blades, then you should tension go a blade size in between these two tension points (e.g. 1/2" according to the built-in tendioning gauge) for your measurements to split the difference. However, there may be some advantage to be had tensioning to the full tension if your widest blade, so you will need to see which works best for you, but pick one or the other.

What you will need is a 4' to 6' box level (must span from top of upper wheel to bottom of lower wheel) with a precision ground face, a jointer and thickness planer and some blocks of wood. A level of this sort is also handy to keep around the shop for setting up jointer beds coplanar with one another and for leveling your tablesaw extension wings. If you can not find a box level with a precision ground face then you will have to invest some time and energy ensuring whichever face of the level you intend to use is in fact flat and true over its length (this is not always the case).

You will use the level to span the distance between the wheels, so it must be long enough to do the job. You will use the custom milled wooden blocks you will be making to span the gap where the wheel housing prevents the level from making direct contact with the wheels. Obviously, you will want to remove the table from your bandsaw as it will be very much in the way. You may wish yo make the second block a known amount shallower than the other (1/8" to 1/4" fir example) as this will prevent it from making direct contact with the second wheel, ensuring that you are resting squarely on the first wheel (likely secured with clamps for one-person operation). You can then use setup blocks, or some additional custom milked wooden feeler gauge blocks (1/8" or 1/4" to match the degree to which you shortened the second block) to feel the gap between the second wheel and the spacer block attached to your level.

With respect to the spacer blocks, use your Jointer to flatten one face on each, then use your planer to mill them to final, and perfectly even, thickness over their length. The length of each should be somewhat longer than your wheels are tall, but not so tall that they can not fit in the wheel housing assemblies. Like I mention above, you will likely find it helpful to mill one spacer block slightly shallower than the first. Then devise a means to secure these spacer blocks to your level, spaced an appropriate distance apart.

When you are making your measurements, bear in mind that the tracking adjustment will alter the wheel's angle as it toes in or out. Try to adjust the blade so it us running, and tensioned, at about the center if the wheel. Do not obsess if the upper wheel, when adjusted, is not perfectly parallel do long as it is close when the blade us reliably tracking on the wheel -- just make sure the upper wheel is centered above the lower wheel's plane and not offset significantly to one side or another. Also keep in mind that at lower tensions the upper wheel may rock a little from side to side due to free play in the tracking and tensioning assemblies, so concern yourself more with gross errors, if any, and do not worry about otherwise small adjustments.

Finally, only make changes to the lower wheel position or angle if you detect gross errors in coplanarity. Do not sweat minor discrepancies as they are as likely to be attributable to free play in the upper wheel as anything else. Minor discrepancies are well within the allowable tolerances for woodworking equipment and are unlikely to affect your bandsaw's proper operation.

I hoe this all comes across clearly enough and that I have not left out anything important. When in doubt think the issue through and the solution will probably reveal itself. If you have any questions feel free to ask and I will try to help when I can.
 

Hmerkle

Board of Directors, Development Director
Hank
Staff member
Corporate Member
Chris,
I suggest you invest in "The Bandsaw Handbook" by Mark Duginske.

Probably THE best reference guide on the bandsaw for set-up and use.

Lots of GREAT info; (sorry the picture is sideways - always a crapshoot with my phone)

MD_-_Coplaner.jpg

 

MagGeorge

New User
George
My older 10" band saw sits on my shop for years already. I haven't used it since I got the 14" saw. The main reason I stop using the 10" due to terrible vibration and balancing the wheels was hard to deal with. I can somehow relate with the issues you have in your Rikon. Should probably check my saw and try to evaluate if I could still save it from being a handicapped tool on my shop. Great info. Thank you.
 

Truefire

New User
Chris
Great information. Thanks Ethan. No worries about your write up, it was all clear and understood. Thanks for providing such a thorough response. I was not expecting so much effort but I do appreciate it so very much. Highly useful.

Hank, definitely going to end up getting me one of those manuals. Im certain it holds some other nuggets that I could benefit from.

Thanks a lot gentlemen.
 

ehpoole

Administrator
Ethan
Chris,

Just let us know how your efforts pan out when you are done as I know we will all be eager to hear back. :)

If my posts help even one member, whether yourself or any other member struggling with their bandsaw, then they were well worth the time and effort to write up. The whole reason we are all here is to share, and archive, our collective knowledge with one another.

If this thread happens to close before you finish your work, please ask any admin or moderator to reopen it for you via either PM or the Help Desk.
 

ehpoole

Administrator
Ethan
Just to add another thought into the mix (rereading this thread), have you tried another blade or two since to see if you get the same vibration?

You can get some rhythmic vibration from the blade itself as the welded joint in the band impacts the guide bearings, especially if the guide bearings have been snugged up tight to the blade (there should always be a gap between the blade and guide bearings to prevent this).

On a similar vein, if the belt was not joined perfectly straight (it happens) then not only will the blade wonder across the wheels in a rhythmic manner (once per revolution of the blade) but it will also tend to slam against the rear guide bearing -- but this is usually rather loud, quite rhythmic, and often rather alarming when it happens (such blades are best returned or discarded as they are useless if it is at all severe).

In either case, one set of guide bearings is typically integrated into the table's trunion assembly where it could very well impart unwanted vibration directly into the table by way of that trunnion assembly.

Just another avenue to explore before you dig in too deeply.
 

Truefire

New User
Chris
Thanks Ethan, yeah I had considered it could potentially be that particular blade that I have installed. I do need to take the time to run a few different blade widths and type around a time or two in order to determine if the issue is the blade(s) or not. Its just that my saw is just so aggravating having to adjust for all those guide bearings after changing blade widths.

I can safely say, we can rule out the bearings from being the issue, they are all adjusted to maintain a space 'off the blade' and only touch when a load is imposed. This goes for both sets. As far as tension goes, after installing a blade, I tighten it just about a 1/4 or 1/3 turn after the wobble leaves the blade. So I think I am good there. I am beginning to lean more towards this being a blade issue because it just seems to be too rhythmic and structured to be otherwise.

I will definitely fill you in on results when I discover them.
 
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