Help needed with SIP bandsaw - blade guides not true?

[Iant61]

Hi folks

Just picked up a used SIP 14 inch heavy duty bandsaw. Been giving it the once over but one thing is puzzling me, the blade guide assembly and hence the top blade guides are about 3 or 4 degrees out of line with the centre of the table.

It doesn't track straight at present but was going to get a new blade as the one on it isn't in a very good state before I tried to set it up properly. This is my first bandsaw so nothing to compare it with I'm afraid so any advice on if this is 'normal' or something to worry about much appreciated.

Ian

 

[Frank S]

Try Steve Maskray`s DVD, that will sort you out and put you on the right track, and get the blades from Ian at Tuff saws.
With this little lot, you can`t go wrong.
Frank S.

 

[Eric The Viking]

Do you mean they are twisted, or that they are just offset front-back or left-right?

I have the 12" version of the same saw (most probably). The guides are fully adjustable. left-right, front-back. Use a 4mm Allen key on the bolts in the centre of each rotating guide (bearing): loosen them and you'll find they all slide. If they don't, probably everything needs cleaning!

I found that mine weren't aligned nicely where the guides assembly is bolted to the blade guard (the telescopic bit). After sorting that, it's fine. The blade on mine doesn't run in the centre of the circle, it's offset. I use MDF discs cut to fit the blade's actual, preferred position, instead of the supplied plastic throat plate, giving a zero-clearance effect.

At risk of repetition, because it's often quoted here, get hold of Steve Maskery's DVD on bandsaw tuning. Everything you need to be able to do to the saw is explained by Steve, with a couple of minor exceptions* for the SIP, which are easily sorted. Steve explains how to make throat plates, too. It's easy once you know how, frustrating if you don't.

Regards,

E.

*Mine was nicely modded by a previous owner to have dust extraction right under the tabletop, instead of from the bottom of the lower wheel housing. It works really well, but you lose a small amount of throat height. The other thing was the bottom wheel spindle. I had to grind flats on it (at the back of the saw, outside end of the shaft beyond the adjusting bolts). to enable me to get a spanner onto it, for setting up the wheel alignment properly.

 

[Iant61]

Thanks for the replies. The problem is they are twisted and there is no adjustment for twist (that I can see). The odd thing is there is no obvious reason for the twist and nothing looks to have been bent but will take the telescopic part of the top blade guide off tonic and have a more thorough look as its angle is set by the outer edge if the top wheel casing.

 

[Eric The Viking]

If you can, please take a snap, from the side/front, showing the guides and the bottom 3" or so of the blade guard above. I've got a good idea why it's happening, but I don't want to send you on a wild goose chase. You need to post a few more messages (dummy ones will do), before the system lets you post up links or pictures. There's a sticky posting on how to show images at the top of each forum section.

. . .

Fettling mine basically involved a complete strip-down of the upper part of the saw, cleaning and lubricating everything that needed it, then reassembling and setting up with new blade(s) from Tuff Saws. I also did the bottom wheel, belt tensioner mech., and cleaned the belt and the pulleys carefully with a toothbrush and slightly soapy water (not on the motor pulley though -- it's mild steel and will rust if soapy water is allowed to dry on it).

It needs another workover this summer, but I have had it running very sweetly, as did the previous owner.

I've only one issue at the moment: being driven, the bottom wheel takes the most punishment, and in mine the bearing has worked a bit loose - there's more play than I'd like. It's the wheel casting, not the bearing itself (which is fine), and I'm not sure what to do about it. The bearing shell is presently Loctited in place, and seems OK, but at some point it will need the equivalent of an engine rebore - out to the next size bearing shell, I fear.

Otherwist the machine is pretty good. It usually runs without significant drift and cuts very cleanly. I think yours will do 3/4" blades - mine being smaller is only supposed to go up to 5/8" but it tensions those well. It's equally good with 1/4" and smaller for very fine curve cutting - bandsaws are such versatile machines!

Regards,

S.

 

[Iant61]

Thanks for your help, will take a picture this evening and get that posted.

 

[woodaxed]

i found bandsaw handbook by mark duginske really helpful when i first started using a bandsaw some 20 odd years ago its still in print a little expensive but worth it and theres always second hand ones for sale on amazon, tbh i prefer a book as you can hold it in one hand while checking
the bandsaw

 

[Iant61]

Hopefully attached some pictures showing the top blade guide in relation to the fence (which is at 90 degrees) and some pictures of the various angles of the blade guide.

Ian

 

[Eric The Viking]

It's exactly the same as mine.

1) The aluminium fitting on the bottom (red ringed) doesn't sit well on the blade guard. Also,
2) the arrangement that clamps the blade guard against the inside of the frame (the big orange wingnut) can cause it to be twisted.

I think what I had to do (similar problem) was strip it - take off the blade guard and dismantle to sort out (2)
and for (1), take off the bearing mounting, and file the place (blue ring) very carefully where it clamps onto the blade guard until it was reasonably straight. I can't remember if I did the ribs on the blade guard (think so) or the bearing carrier mounting bit).

I don't think there's a simple "just bend this" sort of fix - it's poor design really. If you file it you can't easily take off too much, as there's plenty of adjustment in the bearing carrier itself, but check it's not bent before getting too energetic.

Sorry I can't be much more help.

E.

PS: Except for one thing: when you have it dismantled, round over the top front corner of the aluminium extrusion ofthe blade guard where it almost touches the top wheel. If I had a pound for every time I've skinned my fingers on it changing blades...

 

[Iant61]

Glad to know its not just me . I think the big problem is the screw that holds the blade guard. As you say it has a tendency to twist in the rails at best so will start there. The blade guide looks to be quite square to the blade guard so if I sort the guard I think that will fix most of the problem.

Thanks for all your help

 

[Eric The Viking]

I think it is a good idea to take the guard off and rebuild the assembly on the bench. That way you can check for squareness (flat surface plus a pair of engineer's squares and check for wobbles and cracks of light, etc.) When that's 'known good' you'll be able to see how the guard sliding mount arrangement is working in the saw: fit it back in place; drop it down and put a straightedge along the mounting and check for parallelism with the slot in the table.

Then lift it a few inches and repeat: not quite so easy to check, but you can see if it's twisting in use. On mine, the guard isn't perpendicular to the table under high tensions. It's basically because the frame isn't strong enough to cope with the twisting forces (I'd expect all small bandsaws are similar, as they're all basically the same construction method). I've fettled the machine so that the blade is as square to the table as possible - important for cutting tenons, etc., but it means it diverges from the alignment of the guides! So, at different depths of cut, the guides can rub or not.

I've decided I can't win on this. The workaround is one of two choices: either (a) set the guides up for a cut of, say 3" as a compromise, and accept it will be wrong for bigger or smaller depths of cut, or (b) adjust it every time.

I don't have a "general purpose" blade, so I tend to go with (a) for resawing and tenoning activities, and (b) for small blades, where it matters: it's important with small blades to get the rear guide just right, as it keeps the teeth of small blades from being fouled by the side bearings (which will quickly blunt them). The rear guides (above and below the table) support the cutting section of the blade, and that's more important using small blades than big, because the blade is more elastic and easier to distort.

Note that considering twist, the blade guard alignment has to be good, but doesn't have to be perfect. One of the advantage of Ian's blades (TuffSaws) is that they have a good set on them (the spread of the teeth) compared to the thickness of the blade material. This makes curve cutting easier, but also means that the teeth are not guided by the rest of the blade in the kerf - at least not as much as with poorer quality blades. I've found it far easier to eliminate drift with TuffSaws' design than with the ones you can buy retail.

Hope that helps.

E.