Kity 513/613 owners or anyone with flat bandsaw wheels! >

[OscarG]

I bought a Kity 513 a few months back, came with a 1/2" blade. The blade was positioned with teeth hanging off edge of wheels:

I want to make a bandsaw box so I've just swapped out the blade for a 1/4" and tried to do the same, i.e. have the teeth hanging off the front but can't do it as the blade keeps coming off. I'm turning the wheels by hand but as I slowly apply tension the blade keeps popping off with a bang. I've had about 4 or 5 goes at this, I can't even get it close to front of wheel before it pops off.

I've now got the blade tensioned but in middle of wheel, would it be horrendous to use the blade like this? >>

For flat bandsaw tyres the teeth are supposed to hang off edge right?

I haven't switched on machine, thought I'd ask you chaps first.

Anyone here got a 513/613, how do you position a skinny blade on it?!

Is there a trick to do doing this?

 

[Lazurus]

Check your wheels are coplanar sounds like something not quite right if it is pulling the blade off the wheel.

 

[Beau]

Check your wheels are coplanar sounds like something not quite right if it is pulling the blade off the wheel.

As above would be my guess. There is a means to adjust the lower wheel on the Kity and yes the instruction for mine said to run with the teeth just off the front and it always worked but didn't often run such small blades.

 

[OscarG]

Thanks guys.

The old 1/2 " blade cut beautifully, would it have performed that well if the wheels weren't co-planar? I'm really annoyed with myself, as I took loads of pics of top wheel with old blade, even made videos showing tension, but didn't take any showing blade on bottom wheel, I guess that would have answered the co-planar question?

Edit - just found a pic of bottom wheel, the blade teeth were hanging off edge of that too. So if both top and bottom wheel had teeth hanging off edge the wheels must be co-planar no?

I've done a lot of searching on here, seems there's a fair few having problems getting a small blade to stay on. None have really shared what they did to fix it though!!

What's confusing me is I've seen a couple of this forum's respected "heavyweights" say the blade position on a wheel doesn't matter as long as the blade is North and cuts straight with no drift... although don't know if that advice extends to flat bandsaw wheel machines too.

So confused! :?

Stupid bandsaws, why are they so complex?!

 

[Beau]

This is my understanding of why you should run with the teeth off the front on the Kity

As the wheel has no camber when you run the blade fully on the wheel the set of the teeth will be pressing into the tyre on the wheel. Two potential problems from this. One the set might get negated from being pushed flat and secondly the teeth may damage the tyre. If neither of these things occur I cant see a problem with running the blade further back on the wheels. Only speculation though as I always ran with the teeth off the front.

 

[sunnybob]

Tension set too high would ping the blade off the wheel. Thin blades dont need anywhere near the tension of thick blades.
adjust the top wheel with the blade loose so that the teeth are where you want them to be. slowly increase the tension untill it is difficult to turn the blade past 45 degrees by finger and thumb at the cutting point.

 

[CHJ]

I let the narrow blades run where they are most comfortable and give best tracking.
I see no excessive damage on my wheels by running with 1/4 and 3/16 blades in the middle, and they are not used on light cutting loads either.

My machine is not a Kitty but if my tyres are supposed to be crowned then it is so slight to be indistinguishable from flat.

 

[powertools]

I own a kity 613 but to be honest I only use 1/2 inch blades in it and the teeth run just over the front of the wheels.
Looking at the manual it says it will take 1/4 blades and the set up is the same.
Don't get involved with all this coplanar stuff if that was wrong you would have problems with all blades.
I think you may be putting too much tension on the blade.

 

[OscarG]

Many thanks for all your replies chaps, hugely appreciated.

Not sure it's the whole issue but from reading your comments I think I might have over tensioned it. With a bit of pressure I could deflect my 1/2" blade no more than about 3 or 4mm sideways. I was (I guess stupidly!) trying to achieve the same level of deflection with this 1/4" blade, having said that, this thing was repeatedly popping off the wheel with just a tiny amount of tension.

I asked Ian at Tuffsaws, (what an absolute gent he is!) if I could pick his brains on this issue. He said he has a small Kity too and always runs small blades in middle of wheel and never had any problems!

So middle of the wheel it is, can return to my bandsaw box now!

 

[MusicMan]

A simple way is to tune the "ping" of your blade to the same (musical) pitch as the properly set up 1/2" blade. If you can't memorise the sound, a cheap guitar tuner would do.

As shown in various online posts, the tension in the blade is the same whatever the thickness and width for a fixed length and material. A thicker/wider blade will of course need more applied force to ping at the same pitch.

 

[Chippymint]

I have just bought-back my old 613 and it had the same problem as you describe. My first thoughts, from what you have bee saying, is that you need to get a very good understanding on how to tune a bandsaw. There are some great tutorials on YouTube- Check out one by Alan Holtham doing one on a Record 300e (similar size to the 613). There's a great book by Mark Dunginske called Band Saws which is great. Please be aware that your Kity has tires that where fulcanised on when new and it is common that the tires go spongy with age and use, especially the bottom one. Kity is one of few manufacturers to recommend the tire sits at the front, which is fine when they have not had a lot of use. The machines design also means that the bottom guide assembly has little for and aft movement. Provided the machine has not been altered or adjust incorrectly you will have coplaner wheels and I bet that's not your problem. Understanding the latter and making sure your saw is 100% set up properly, and the problem still exists, you need to replace your tires or do what I've just done which works brilliantly - back off the blade guides and thrust bearing then tension the blade correctly and adjust the top wheel so the blade is in the centre. Then tilt the lower wheel until the blade is tracking in the centre of the bottom tire (this is miniscule adjustments). You do this by removing the motor plate cover at the rear. Remove the centre bolt and plate. You will see 4 adjuster bolts. Adjust the top and bottom ones only. You need to tilt the wheel so the top moves forward by releasing the top bolt 1/4 of a turn at a time and lock it. Then adjust the bottom bolt so it tightens onto the shaft. Spin the wheel by hand. You should see the blade move further to the center. You may have to readjust the top wheel but your aim is to get the blades so the blade teeth gullet is in the centre of the tire. At this point make sure you resecure the rear plate on the shaft. There is one problem you may experience- the lower blade guide assy will need to be repostioned so the guides are in the correct position. This may mean shiming the table trunnion away and also expanding the aluminium adjuster shot (which I had to do). When you've done this and everything is secure, start up the machine and make final adjustments to get the blade in the ideal position. Then tune the bandsaw to get it the correct standard. There is a lot to do possibly a day or two. Ps don't worry about the blade in the centre of the tire. Hope this helps and let me know how you get on or need more help. Happy days