Rikon 10-345 Bandsaw...See the Flaw?

[cpowell]

I have attached a few pics showing the upper wheel tensioning assembly for the new Rikon 10-345 18 inch bandsaw.

I had noticed that it is very difficult to tension/track the upper wheel with any repeatability at all. Rikon tech support has been very helpful, but, I believe they unlocked the mystery when they told me that the upper wheel tension/tracking assembly was redesigned.

I believe there is an absolute fatal flaw in the design from a mechanical standpoint. Look at the pictures below and let me know if you can see it. IMHO this design will NEVER deliver repeatable positioning as-is. If you see something and would like clarification just ask.

If any of you have the 10-340, which had the "old" design, I'd love to see some shots of the upper wheel tension assy for that model to compare.

The first picture shows the entire assembly. The second shows the top of the assembly. Note the slot in this surface.

The third shows a closeup where the tensioning wheel threaded shaft comes through the frame bottom. You can also see the curved surface of the tensioning arm end.

Chuck

[cpowell]

Here's a link to the Review on Insomniac's website. Edit In:...forgot the link...http://shootingboard.net/bandsaw.htm

If you look at the picture of the OLD quick release/tensioner on the back of the saw and then the view of the OLD tensioner assembly on the front of the saw...???

[Monty]

Here's what mine looks like:




I can take more detailed pics if needed. I don't see what you mean as a fatal flaw, though... dying to find out!!!

[cpowell]

Insomniac,

Can you post a pic showing the side view of the tensioner assy at the top showing how the assy is fastened to the frame? The same view as my middle picture which shows the slotted hole where the assembly is pinned (pivot point)?

Look at the location of my saw's quick release tension arm in the picture below and at the opposite side in the bottom picture in my first post, where it bottoms out against the frame.

[Monty]

hmmm... yep, I'd say they DID redesign that sucker!




I'm still at a loss what the problem is, though... does your tensioning arm swing side-to-side instead of around????

[D L Ames]

Same here, I don't see what you are trying to point out Chuck.

D L

[cpowell]

ok, point made.

I wanted to get more info about the old model because I don't want to make assumptions.

The new model compresses the spring, tensioning the band, by using the lower frame as a thrust surface. The blade tensioner assembly/case is NOT under tension...nor is it under compression. My guess is the old model compressed the spring within the tensioner assy case (not sure if that is what it is called), so that the outer case that contains the tensioning screw, etc is under tension.

On the new saw, as you tension the blade, the force is exerted against the frame bottom. When you try to move the tracking adjustment knob, it is working against the friction between the bottom washer surface and the "graphite strips" that were inserted to minimize friction...It does not work. I believe that the old assy likely pivoted about the top pin and the track adjust knob simply changed the angle of the dangle of the whole works.

Look at the bottom picture on my first post. You can see where the tensioner arm ends (the discs with the inclined area, don't know the term). As soon as the arm is turned, there is a force applied at the surface below.

With this new improvement, if you have the blade under tension and back out on the tracking adjustment knob...NOTHING happens. You must release tension to reduce the friction on the bottom in order to allow the band tension to change the angle of the assy.

Net effect..every time you put on a new blade it's a ROYAL PITA to get the blade to track about center. If you use the Timberwolf flutter test, when you release tension, the wheel moves. If you set the saw up PERFECTLY, release tension, reapply tension then attempt to get the blade to return to the location for which it was adjusted it will likely NEVER happen. The wheel assy moves left and right freely, meaning you will have a tough time obtaining the same center between the guides if you release and reapply tension.

I can't believe this happened. They took what I consider to be an elegant, simple, robust solution and replaced it with a mediocre solution.

Why would you EVER attempt to tension the wheels by applying compression from a fixed point between the top and bottom wheels? You wouldn't. You'd tension the wheels by applying tension from a point above the upper wheel centerline...I felt that it was probably that wayon the OLD Rikon 10-340 saw.

I'd like to know "the rest of the story" here.

I would not recommend the NEW Rikon 18 bandsaw until they straighten this out. It is NOT the same saw anymore. It does not appear to be something that will be easy to fix properly.

What led me to digging into this was trying to tension a 1" Timberwolf blade. I was not happy with the blade flutter and called Timberwolf tech support. They asked me if the saw was an old Rikon or a NEW Rikon. When I said, "New" the guy said, "Oh, boy. I was afraid of that". After applying Timberwolf blades on Rikon 18 saws for a long time with NO complaints, he had received four complaints in the past 3 weeks on the NEW model.

[Monty]

Wow. Just wow.

Sorry about that... don't know what they were thinking with that re-design. I remember you PM'd me about having problems with tracking adjustment under tension... now you have finally figured out why. I can detension/tension mine without changing the tracking, and adjusting tracking is fairly easy under full tension. (I don't turn the de-tension lever all the way - just enough to break the tension but not so much that the blade slips on the wheel)

Now I will say that I did put on my 1" blade briefly just to check it out. It didn't track right, but then again I didn't try very hard to tweak it. I didn't really need it at the time, just wanted to check the fit and tension. I'll try it again and see how it goes... maybe tomorrow or this weekend... I'll let ya know.


WOW.

[D L Ames]

Hey Chuck, thanks for posting that clarification. It all makes sense now. BTW, if you decide to scrap that new Rikon can I get that new CI table trunnion assy from you.

D L

[Monty]

Originally Posted by D L Ames

BTW, if you decide to scrap that new Rikon can I get that new CI table trunnion assy from you.

that's cold, man!

[cpowell]

I am actually posting as an offer to trade a brand new, improved Rikon 10-345 for an OLD 10-340. My new saw has the cast iron trunnions, a newly designed tensioning assembly and a brand new cast iron table (the table that shipped with the unit was defective).

[D L Ames]

Originally Posted by cpowell

I am actually posting as an offer to trade a brand new, improved Rikon 10-345 for an OLD 10-340. My new saw has the cast iron trunnions, a newly designed tensioning assembly and a brand new cast iron table (the table that shipped with the unit was defective).

Chuck, I am sorry to hear about the problems you are experiencing with the newer version of the Rikon. I forgot you originally mentioned that you had a bad mounting hole on your original table. Like Insom, I am going to have to put my 1" Timberwolf on the saw this weekend to see how it tracks.

D L

[Monty]

OK. Took some more pics tonight. The pics I posted above show how the placement of my tension lever differs from yours. This pic shows how turning the lever changes the tension on the blade:




On the left is tensioned, right is detensioned. Hopefully you can tell that the lever turns a cam, which lifts the whole spring assembly/upper wheel to apply tension to the blade.

Just to complete the comparison, here is the bottom of my spring assembly:




You are right about the tracking knob - looks like it just changes the angle of the whole assembly - the wheel and spring assembly and tension adjust wheel at the bottom all swing as a unit, pivoting from the pin up at the top. I've got to say, I'm not sure why a re-design was necessary - I have not heard about problems with this design. Probably lowers the production costs by a few cents...



FWIW, I also went ahead and put my 1" Lenox bimetal blade on there tonight and took it for a little spin. Tensioned up just fine based on the built-in scale, and as well as I could tell with the flutter method (this thing don't flutter much ). When I applied full tension I did have to adjust tracking about 2-3 turns, but then it tracked just fine. Cuts pretty sweet, too.

I mentioned before that I had a trouble tracking that blade when I first tried it on... well, it was because I forgot to back off on the lower thrust bearing.

Anyway I hope you can resolve your problem.

[cpowell]

Here's the gist of the problem as I see it.

On the OLD (10-340) design, the lower wheel is fixed. To apply tension, the upper wheel is PULLED from the top surface established by the tension arm (quick release). Similar to how you would use a come-along , or, mor closely, a turnbuckle, to PULL a truck out of a mudhole. The beauty of the system is that the ANGLE of the tension is controlled by the tracking knob. The ONLY force that opposes the tracking knob is the tension of the assembly (or band).

The NEW design (10-345) is like using a turnbuckle to PUSH a truck out of a hole. NOBODY would do that! Control of the angle of PUSH is difficult to near impossible IMHO. When pushing the tensioner assy with the tracking knob, the friction at the bottom bearing point (washer) will determine whether the assy moves in relation to the centerline of the wheels. When the tracking knob is loosened to cause the top of the upper wheel to move toward the front of the saw and cause the blade to move toward the back of the saw, the motion is impeded by the friction of the bearing surface (washer). The fact that the bearing surface is flat is a huge hindrance because the angle of the axis changes relative to the surface as the tracking knob is moved. This is a huge problem.

I don't know if the explanation is clear, perhaps a more mechanically inclined person can explain better. In practice it makes blade tracking and overall alignment MUCH more unstable than the OLD system. I believe that the value to money ratio for this piece of machinery has decreased.

Again, the proof's in the pudding. Timberwolf tech support has echoed this sentiment. They are now fielding calls from owners of the NEW Rikon model 10-345 who are attempting to use 1 inch bands for resawing and are experiencing problems.

[sapwood]

What a Bummer

But thanks for making the NCWWer community aware.

Sapwood