Kity 613 Problems

[xraymtb]

Hi all.

Picked up a 613 a few weeks ago, first blade fitted was a 3/8", took some fiddling to get it to track on the edge of the wheel but managed it eventually and well tensioned. Happily resawn 8" dry oak since.

Tried to fit a 1/8" blade today and cannot get it working for the life of me. All guides backed off, I get the blade on, begin to tension, checking the tracking as I go, and as it gets near the right tension it seems to get stop reacting to the tracking, sliding off the wheel with a bang, even with the tracking cranked as far as possible the other way. Tried setting it up mid wheel - no luck. Tried setting the tracking before tensioning (i.e. fully towards the back of the wheel) - blade goes off the back. I've checked the wheels for coplanar, might be slightly out but need a 22mm ID washer that I can't pick up locally.

Anyone able to help?

 

[marcros]

this may not be relevant, but somebody had an issue on the forum previously, and the because was that a tiny turn of the tracking knob made a huge difference- they were giving it quarter of a turn and that was the difference between it shooting off the front or off the back. I dont think it was a kity but may be a possibility it is a similar issue.

 

[xraymtb]

It could be. The Kity has flat tyres rather than crowned - I'm sure it makes tracking harder. If I don't get any more feedback it will be another hour tonight of trying fine adjustments.

 

[carlb40]

You wont get it to work. The smallest blade for a 613 is 1/4" or 6mm according to the specs.

 

[Eric The Viking]

I'm with Carl on this one.

If you think about how the same tracking system has to cope with a range of blades, if the adjustment works at 1/2", it's going to be really coarse at 1/8". The tooth set makes the cross section of the 'fretsaw' blades much more 'triangular' than with deeper, bigger blades, too, and if your wheels aren't crowned that makes it even harder: the crown helps blades stay in place as they have a self-centring effect (that's why the old flat-belt-driven tools always had crowned wheels - the crown is often subtle but it's there).

That said, I know Steve Maskery runs some very small blades on his big Basato (5?). I also know he does have to alter the setup a bit to run the smaller blades well, but I can't remember the exact details (I think at least it involves not using some of the guides because they become impractical). He's somewhat "workshop-committed" at the moment, but if he spots this he may comment. He also mentions small blades in his bandsaw DVDs, but I don't remember the detail - the smallest I've ever had to go on my SIP is 1/4" which is a bit "fun".

Also it might be worth asking Ian at Tuff Saws what he recommends. I fear that a widely set 1/4" blade might be just as awkward (small, triangular cross-section again) - it's not the thinness of the kerf but the larger angle of tooth set that you need for twisty work.

It may be a design limitation you can't easily overcome.

One final thought: The wheels on mine are crowned in the aluminium itself. They take a flat tyre, which conforms to the shape when you fit it. I was surprised about this, as it looked as though the tyre was thin and crowned, feathering to almost nothing at the edges. In fact it runs in a wide slot in the rim, the floor of which has the crown. When I changed the tyres, the old ones didn't look very crowned, as they were well worn. New tyres gave the wheels a much more pronounced crown, and tracking vastly improved.

Are you sure your wheels aren't crowned (I know some really aren't). If they're not, they are probably meant to take crowned tyres. Could it be either that the tyres are very worn, or that someone has fitted the wrong type in the past?

Crowned tyres won't work as well for bigger blades on smaller wheels, as the rubber will distort under the higher tensions, but they should be fine for small blades. It's not a general purpose solution, but if you want to keep the machine for fine work, that might be the way to go.

Radically, If there's a groove for the tyre, I don't think the tyre length will be absolutely crucial, as long as it fits snugly (you might need to stretch it a bit more if it's smaller, but that's about it). So whatever fits will serve. Different matter with bigger blades though.

I fear you might have to choose - set the machine up for big blades or small - and accept you can't do both optimally.

E.

 

[xraymtb]

It is designed with flat tyres rather than crowned. Had it working last night until I tightened the locking nut on the tracking and must have moved it a touch. Cue blade running off again.

 

[Eric The Viking]

It is designed with flat tyres rather than crowned. Had it working last night until I tightened the locking nut on the tracking and must have moved it a touch. Cue blade running off again.

Crowned tyres could only help, if you can find some of the right size.

 

[xraymtb]

I did wonder that, the tyres are not completely ruined but aren't perfect either so I wouldn't feel bad replacing them.

I had thought the crown normally comes from the wheel though?

 

[Eric The Viking]

I think it depends.

The Startrite bandsaws I've seen have pressed-steel wheels. Those are cylindrical, and I remember Olly documenting how he replaced the tyres on his and crowned them carefully by hand(!). I've also seen crowned tyre material for sale on the Net (in the USA at least).

In contrast, the tyres for mine are rectangular in section, and as you say, the crown is turned into the aluminium wheels. But mine is small and really a hobbyist machine.

 

[xraymtb]

I've got it working in the last hour, took very careful tweaking of the tracking, not too much tension and guiding the blade away from the wheel edge when it got too close as I was adjusting.

It seemed that the tracking was able to get the blade steady in one place but not move it significantly at tension. For example, if the blade started to move forward towards the edge, even turned fully the opposite way, the tracking couldn't stop it slipping off the edge. If however I used my finger to guide it back to the middle of the wheel, then the tracking could be adjusted to stabilise the blade.

And for anyone who reads this in future, don't try to run the teeth off the wheel edge like you do for bigger blades - the blade is too narrow and will jump off.

 

[Racers]

I always run the teeth on the wheel on my Startrite 352.

Pete

 

[woodbrains]

Hello,

The tyres are definitely NOT crowned on a KITY 613. The teeth have to run off the front edge and I doubt it will leave enough blade behind the gullets on an 1/8 in blade, to work. The only option is to run the blade fully on the tyres, which you should be able to track, but the teeth will likely cut up the tyres after time and you'll likely ruin them for every other blade you have. I think replacements are extremely hard to get, so I'd try to keep the tyres in good condition for as long as possible. The saw is not specified to run on blades narrower than 6 mm.

I have a user manual, which I could copy if you do not have one.

Mike.

 

[Eric The Viking]

The tyres are definitely NOT crowned on a KITY 613.

Ouch. That can't make life at all easy.

 

[woodbrains]

The tyres are definitely NOT crowned on a KITY 613.

Ouch. That can't make life at all easy.

Hello,

I've not used one in years, but to be fair to it, it was easy to tension and never suffered from drift, which I partly attribute to the fact that the blade remained flat across the width. Crowned wheels can sometimes toe the blade slightly in or out, which is one cause of drift on some saws. All the blade widths it was designed to use, worked well, bu 1/8in is pushing the boundaries on this saw.

Mike.