Thread: Carbatec CTJ-3501 not tensioning

Originally Posted by Lyle

I am hoping someone will be able to post up a photo or two of their tensioning mechanism.
I replaced the upper washers with a thrust bearing.
I did take photos and believe I put it back together correctly.
But now it doesn't tension the blade.
Bought in 2006.
Thanks in advance.
Lyle

Why? Why did you change the washers? Maybe put the washers back in and then get that working and establish what is different?

This is a snip from the manual and it does appear that it may be put back together incorrectly
You can get the full manual here
https://www.carbatec.com.au/document...S-X3452C_1.pdf

Rick



Opera Snapshot_2020-07-03_212808_www.carbatec.com.au.png

It was full of dust/grease. So I cleaned it up. Used a thrust bearing to replace the two flat washers. They worked out the same thickness.
Thrust bearing works a treat.
Will be better when I get it tensioning again.
I did reverse back to the two washers, but same problems.
Definitely not right.
I'll check out that exploded view, thanks.
Lyle

Contacted Carbatec. They are going to email me two manuals, one for the old CTJ-3501 and one for the newer model.
Hopefully I'll be able to see what I've done wrong.
I went the thrust bearing as it has always been tight to tension. But now I've obviously screwed up somewhere.
But for the life of me, where?
There's only a couple of bolts holding it together and they are in predetermined holes. It has gone back together as per the photo I took (see original post). AND it hasn't been apart previously since I bought it new in 2006 at Carbatec in their old shop in Cambridge st Brissie. Geoff sold it to me at a discount as the paint wasn't the correct Carbatec colour.
I dunno. It'll be something simple.
Lyle

In the pic you’ve attached, the cam looks to be released, have you turned that back to tension.

More research shows this CTJ-3501 as the same as a Grizzly G0778.
The exploded view doesn't help as it is all there....
Is it just a setup adjustment possibly??
Lyle

Thanks CJ, yep I've tried that.
Still stumped.
Back out to give it another go.
Lyle

Am I missing something here but you have no upper wheel or blade on there to allow you to tension it. Is this just a staged shot to show us the mechanism?
Are the washers you replaced with the thrust bearing those at the top (left) of the black bracket?
Does the aluminium block that the wheel mounts onto slide up and down freely without the blade on? Are the 2 bolts that go into the side of that block free to slide freely in their slots? I don't know if you pulled all of this apart while doing your changes.
Below are some photos of how mine goes together. Mine doesn't have any washers or thrust bearing on the top of the black bracket.

IMG_20200704_200644.jpg IMG_20200704_200721.jpg IMG_20200704_200845.jpg

Lyle,

In your pic the cam is not in the tensioned position yet the spring is compressed.

Something is odd.

I think for one the cam is 180 degrees off ( a guess) and the added thrust bearings are stopping the sliding bracket rising. Pull it apart and put it back together , referring to the pics above.


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Thanks Dallas. Yep photo with wheel and blade removed. Note this is as it was, with the two washers between the tension bracket and threaded rod. I've reassembled it as per the photo. Only difference is replacing flat washers with a thrust bearing equal to their thickness.
Thanks elver. I haven't touched the tensioning arm cam at all.
I will try again without the washers or thrust bearing.
I've also now got the Grizzly manual which is identical to this old CTJ-3501.
Lyle.

Thanks for all your replies, very much appreciated.
Using the exploded view and the one from the Grizzly manual, I took off the two washers between the bracket and tension knob. Also adjusted and retightened the threaded sleeve under the handle. (I hadn't checked it previously).
Turns out it was loose. It had moved. So maybe that was why there were the two extra washers. I have not pulled this apart so they were in there when I bought it back in 2006.
So that and the fact I had two extraneous washers made all the difference.
Tensions and tunes very well now.
Happy camper.
Thanks again for your replies.
Lyle.

When you are screwing the adjuster down is the whole assembly rising even without the blade on? Without the blade on you should be able to push the whole assembly up by hand and it should freefall under its own weight until the end of the adjuster is back on the cross bar.
Whether you have the washers, trust bearing or nothing at the top it shouldn't stop the adjustment working properly. The tension cam in my photos is in the relaxed position (sitting on the small flat). I normally adjust my blade to get some tension with it in that position and then turn the handle towards the front of the machine to apply the final tension. This movement will put the cross bar on the high point of the cam. If it's not right I back off the handle, readjust and then turn the cam again. On yours, just turning the tensioning lever one way or the other you should see the whole assembly move a little bit. If you don't then something is preventing it from moving.
Elver, I understand your confusion with the spring as it took some time for me to understand how the system works when I saw the photo. The fact that the adjuster is screwed down to lift the whole assembly it compresses the spring at the same time which is what makes it apply tension to the blade, and allows for different width blades without having to screw the adjuster screw a long way for wider blades.

Looks like I was too late with this reply as I was typing at the same time as you. Good to see you got it sorted. Sometimes its just a small thing that is easily overlooked.

Good to hear all is now resolved.

Bandsaws with the cam action quick tension lever assembly do not seem to have the same tensioning thread adjustment range as bandsaws without that feature. I found on my Woodfast BS500 that there were two band lengths quoted in the manuals and on a label attached to the machine. Only some 25 mm different but the longer length could not be tensioned sufficiently with the larger 1" x 1.3 tpi blades as there was just not enough adjustment. My local saw doctor would not believe me until he had a look for himself!

It also pays to check out new machines which have been "assembled for your" as my bandsaw table was not fitted per the parts diagram and the assembly instructions in the supplied manual.