BMT250 setter problem

[Southside]

Finally got around to setting up my setter - BMT250 at the moment as the motor is not on it - as my mountain of dull bands was far out pacing what few sharp ones I had left.  Got it all dialed in but for the life of me I can not keep the band from rising above the set pins and out of alignment with the anvils as a result.  1 1/4" bands, they drop down into place, when I advance the crank they will sit in place the first time, but on the second round of the crank the right side (as you look at the machine) will begin to pull up from the depth pin and keep doing so until the band comes out of the setting blocks.  I have tried every arm support position I could come up with, natural curve of the band, force it more straight as it comes into the setter, more spacers under the arm foundation block, less spacers, tried the little guides wheel in, wheel out.  Just can not get it to keep the band in place.  

Anybody ever have this issue and if so how did you correct it?

Thanks

[Percy]

I do have the BMS sharpener but not the setter. I use a suffolk setter. I did have an issue similar to what you are describing, My set up for this setter is home made but perhaps this can help.

There are usually 4 supports for the blade when on the machine, be it the setter or sharpener etc. Left, back, right, and the machine itself. I have found, on my setter anyway, that I need to have  the left support(Output side) just slightly lower than the level of the "Business part" of the machine. The right side support (or input support) can be a tad lower than the output side but not too much. The advancing action on my machine tends to slightly lift the input side so the more weight you have on the input side  helps. Try extending the input side while shortening the output side if you get my drift. The support directly opposing the "business" part should be close to what the business part is but on my setter, it seems to be  not that big of a deal. I have been considering  buying the setter you have. I await your discoveries ......

[terrifictimbersllc]

I have this setter.  Preliminary thing, make sure the elevation of the plastic supports on the long arms aren't causing it. 

You wrote "guide wheel in, out" do you mean the bearings that are on the toggle clamp, either clamping the band or not?  If not, then my following suggestion might be off base.....

What it sounds like to me is that the tilt of the ball bearings on the clamp right before it goes into the right setter block (facing setter), is wrong.  Tilt one way it will drive the band down, the other will lift it up.  There is a jack screw to adjust this tilt.   I would think it would behave properly when this clamp is open as the pusher is always pushing down on the band.  

Also bands that have some abnormal twist in them from an "incident" these will cause trouble, avoid "incidents". 

[Southside]

Thanks Terrific,  the guide wheels I was speaking of are those plastic wheels that go onto the plastic supports out on the tubing arms.  I will look at the bearing clamp for an adjustment and see what I can do.  

I did play with it more this morning and I think part of the issue was that I had the band set too high, following the book it calls for the gullet to be even with the support plate, well with a Turbo 7 that sets the band up way high.  Lowering it and adjusting the arms a bit more helped, but it's still not where I want to see it.  I did try a different band too thinking that perhaps the one I had was sprung.  

Going to keep getting it dialed in, the sharpener was easy to set up compared to this one.  

[terrifictimbersllc]

My setter does not have or need any wheels on the 3 extension arms.  The only wheel I know of is that that goes on one of the sharpener arms, the one on the right, to keep the magnet from being wiped off by the plastic post.  The setter needs only the plastic fittings with the two vertical posts. 

Another thing about setting with the bmt 250 setter I have learned, is to have the blade as low as possible.   The lower the tooth is, the more the pushing action tends to actually bend it rather than just spring it over and back.  This is a subtle thing but you can see it in the gauges, there is less deflection required to get a set.  I think this lends to more setting of the under-set teeth and less setting of those that already have a higher set. Could be wrong but that's where I am now.   There is a limit to how low the band can be, the top of the tooth obviously needs to be at least a third of the way up the gauge foot, and the gullet should clear the top face of the bearing that is actuated by the toggle clamp.   I am still talking about a sixteenth or thereabouts max depth below the anvil, not something more dramatic. 

[gmmills]

Southside, Not sure if you have the issue resolved at this time. I received a call from a local sawyer Fri in regards to the same issue you are having. He just recently purchased a BMT250. After a couple of phone conversations through the day on Sat we have solved his problem. The issue of the blade rising as the blade advances is directly related to the red handled blade clamp assembly. If in doubt, try to partially engage the clamp lever to just contact the blade and cycle the setter a few times. The blade should stay down at this point. The pressure exerted by the clamp not easily adjusted. He found a way to loosen a couple of bolts and shift clamp tension block to get enough movement to lessen the pressure. Did not elaborate on exact bolts he used. The whole clamp mount assembly is adjusted from the factory so the roller bearing assemblies are leaning to the left. this helps in keeping the blade traveling with downward force. The manual states that this measurement from the main setter top plate and the clamp assembly mounting plate to have a 1/16" gap.  He increased this gap to near 1/8". With these two adjustments he solved the issue and is happy. Just stay focused on the clamps physical forces that it applies to the blade.

[Southside]

@gmmills 

I have it working better, but still not where I want it.  I looked over the clamp and the only adjustment I see is on the back side of the clamp assembly - the part that does not move - at the bottom are three shims that set the width and by default the overall clamping tension.  That must be what he adjusted but I am not following you about the gap you mention.  

[terrifictimbersllc]

Diagram from manual shows the 1/16 "gap" is that created by the "Clamp Adjustment Set Screw" lifting up the "clamp mounting block".   This is a jack screw the tilts the red handled clamp assembly to the left.



Below is a photo of my setter with an orange wire tie pointing to this "jack screw".  "Jacking up" the clamp block with this jack screw tilts the assembly to the left. This tilt causes the blade, passing from right to left and clamped between the two bearings, to be forced  down onto the top of the metal dowel seen to the right of the clamp mounting block in the photo.



NOTE: The clamp being discussed here is the red handle clamp and is NOT TO BE CONFUSED with the other clamp which opens and closes on the blade as each tooth is set.   Coincidentally, there is also a 1/16" gap important there too, that being the amount that the gullet of the blade is below that setting clamp/anvil.  That adjustment is made using the blade height star knob. 

[Southside]

Ok. I will try adjusting that before I mess with the shims.

Thank you

[terrifictimbersllc]

Wondering where the shims are you are referring to. 

[Southside]

Screwdriver tip is touching them. 


 

[terrifictimbersllc]

Thanks. now I see them also  in the parts diagram, 3 of them.  Didn't know about them before. I believe I adjusted that bearing clamp pressure once early on  by changing the washers at the end of the clamp rod.  Don't remember why.  

I do know that I had to adjust that jack screw once, increasing the lift/tilt/gap to always keep the blade on its posts.  

I think a good strategy with this setter is to increase set as little as is absolutely necessary and to keep the blade as low as is practical in doing so. 

[gmmills]

The diagram from the manual that Terrifictimbers posted shows the gap I was referring to. The gap needed to be slightly increased. Concentrate on the clamp pressure itself. The pressure is created by compressing the rubber washers that are located just behind the large fender washer at the movable side of clamp fixture. There are 3 rubber washers supplied. May want to try lessening pressure by omitting 1 washer.   Try this to confirm if the issue is directly related to clamp pressure. Engage the clamp lever fully then release it slightly, have to manually hold it in this position, and see if the blade stops rising while in operation. If so, the problem is with too much clamp pressure.  The clamps function is to stabilize the blade as the advance rod pushes the blade forward.