momo fubard

[momo]

Well today has been a momentous one. First her who will remain nameless and ignored for two weeks told me I could not have my thicknesser ( wont tell what I called her) so in revenge I went to screwfix and bought one of them diddly little triton band saws, BIG mistake, but it was within my wallet which was screaming today for mercy.

Anyway got it home and ran through the manual which may as well of been in swahili, went to tension the blade and suddenly - Ping, it fell off the wheels, nearly slicing my arm with it, ok put it back on I thought, so I did, and then went to tension it again, - Ping snap!!!, ok, so I broke it, I put the spare one on, and re read the instructions, now, as a mechanic, when I do a cam belt I tighten it till I can just twist it to about 90degrees if I dont have my tension gauge, so when it said push till it can only move 1-2mm ( they didn't say if this was side to side or twisting) I tried just that, guess what, Ping snap, oh bu**er the second one went snap........ So of to screwfix in morning to buy another blade.
:?

Her indoors should just of let me have my thickneser, but oh no she had to moan I spent all the fortnights money on ebay!. Did NOT.

 

[Smudger]

I've got the Perform version. It's pretty hard to set up. Well, I've never managed it.

I've got a Ferm somewhere (in France) and it's a dream in comparison. I think I might do a swap.

I used to have 2 Ferms, but I lent one to my mate Glen...

 

[OPJ]

If you're looking for blade deflection, only 1-2mm means it is far too tight. Generally, I think people will tension the blade to get around 10mm deflection for general work; 6mm for heavier re-sawing.

If the blades keep snapping, it's probably down to the machine, yes. But what blades are you using? Are they Screwfix's own brand or did they actually come with the saw?

 

[momo]

OPJ, but does this mean
10 mm deflection left and right when pushing with a finger from the side, or 5mm to the left and 5mm the right, or does it mean 10mm each way deflection by twisting the blade by holding it at the back and front with two fingers or 5mm each way.

Momo always makes it harder than easier :lol: :lol:

I always end up never figuring this out, as a mech I twist belts to test tension, not push them left and right unless specificaly told too.

 

[OPJ]

You're looking for 10mm sideways deflection, pushing against the side of the blade (not in to the tips of the the teeth or the back 'edge' of the blade). You're looking for about 10mm either side.

 

[momo]

momo looks around to see whos watching his post and laughing then whispers to OPJ " do you mean 10mm to the right and 10mm to the left so 20mm overall.

Dont blame me, blame my brain it asks these silly things

 

[Streepips]

give the bandsaw away and buy a jigsaw... Probably cheaper and safer for you and those around you in the long run

 

[mr]

If you're looking for blade deflection, only 1-2mm means it is far too tight. Generally, I think people will tension the blade to get around 10mm deflection for general work; 6mm for heavier re-sawing.

If the blades keep snapping, it's probably down to the machine, yes. But what blades are you using? Are they Screwfix's own brand or did they actually come with the saw?

Olly - really? I tension my blade up to a couple of mm deflection, till it produces a nice clear note when plucked, 10 mm each way is where it lives when I slacken it off out of use. Not had a blade break on me yet, will have to watch Alan Holthams DVD again obviously.

cheers Mike

 

[OPJ]

Well, Mike, I actually go for the 'Pinging' method myself. I only mentioned the 6-10mm sideways deflection because it's something I've read from various sources.

When you check for deflection, do you lift the guard all the way up first?

If the blade keeps snapping, momo, it could also be down to the tracking of the top wheel - if not both of them (but let's look at the top wheel, first!). Is there any information on this in your manual? There should be a knob directly behind the centre of the top wheel, which tilts it one way or the other.

With the power OFF, you should make slight adjustments at a time and then spine the wheel by hand three-or-four times and note whether the blade is running roughly on the centre of the rubber tyres. It's not exactly critical, but it should be close.

It does sound possibly like the wheel is tilted too far in one direction, meaning the blade keeps falling off and going 'bang'!

Mike, I've only two blades break on me in the 18 months I've had my SIP saw. Sometimes they can snap on the weld for no apparent reason - Dragon Saws will usually re-weld their own blades i you send them to them, in this situation. It's quite a shock when it first happens - the tensioning knob jumps out of my saw like a game of Pop-Up Pirate!! :wink:

Bandsaw blades aren't made to last forever. They will become blunt eventually and will need replacing. I've always been told it isn't worth the cost of having them resharpened on shorter blades anyway.[/u]

 

[OPJ]

Mike, after reading you latest article in Good Wood, where you mentioned you were struggling to cut a radius with a narrow blade, I thought you might like to try using an old oilstone or one of these Blade Files to round-over the back edges of the blade.

If you have any problems with burn marks, this should sort it. It works very well for me and it also prevents the blade from cutting a groove in to the thrust bearing. You can even clean up any untidy welds, if you're careful - just watch out for those teeth!! :shock:

I noticed you also don't have any dust extraction with your saw. But, to be brutally honest, I find the one, lower extraction port to be insufficient on its own as a lot of dust builds up around the lower blade guides...

 

[mr]

Olly, you're right I haven't rounded the back of blade but it is something I've been meaning to do, it certainly does sound as though it would help with the marks at least, though to be honest the blade I have fitted and used for that wee box is quite a coarse blade so it's always going to leave marks to some extent though I could do without the burn marks when they appear. The bandsaw is a comparatively recent toy for me only a few months old and I've never used one prior to buying this one so it's all a learning curve.
Re extraction again you're right, I have none and the lower wheel housing fills up with sawdust, as does the area around the lower guides as you say which I clean out by hand as it builds up in an attempt to keep it clear. I have heard tell that a vacuum hose attached under the table near the lower bearings works wonders, again when I get hold of a vacuum cleaner down in the workshop its something Ill try. Never needed a vacuum before as I haven't ever really had that much of a dust buildup - its always been shavings really.

Cheers Mike

 

[OPJ]

I'm hopefully gonna try and conjure something up soon enough which'll have a short length of 32mm running from the 100mm extraction port to lower guides. I can't stand the noise of vacuums personally, so only use my RSDE2-A when cutting MDF.

 

[mr]

I can't stand the noise of vacuums personally, so only use my RSDE2-A when cutting MDF.

That's one of the reasons I've stuck with the dustpan and brush

Cheers Mike

 

[momo]

OPJ.
Having opened the wee beastie up, I found what is wrong I think, first it is not running on the centre of the top or bottom wheels( it is tilted right over so the top is pointing at me!!!. The tensioning bolt is at the top and has a bar attached to it, there is another bolt sticking out the back directly behind this bar, I guessed that this bolt pushes the bar outwards or inwards thus centralising the bladeon the runners, however it was under the bar not behind it and was as such not moving the top wheel or therefore the belt. It now does move the belt and it is now riding centraly on the top and lower wheel. I have found two roller bearings that sit behind the blade, but even with turning the rear bolt to move the blade in our out they seem to go nowhere near the belt so I am wondering what their purpose is, in my line of work a bearing has a purpose and isnt for show!. Incidentaly my manual just says 1-2mm of deflection but it doesnt say if this is overall or 1-2mm left and right.

Streepips, I like your sense of humor, however as a mechanic and with all the things I am qualified to do, I NEVER give up on equipment, I do however have a tendency to go into manuals and such to the extreme and question ambiguous instructions to the nth degree. ambigouity can kill

 

[Mcluma]

Momo, did the blade break on the welt, if so, then you have poor quality, and better upgrade to some better blades

 

[pooka]

The following is an overview of the steps involved in tuning a bandsaw, including how to adjust the thrust bearing and bearing guides (figures L to N - the lower bearings are not shown, but these should be similarly adjusted):

http://www.diynetwork.com/diy/wk_tools/article/0,2037,DIY_14429_2278285,00.html

A better source though, and more detailed, is one of the decent books on the topic. Some good examples are "Bandsaw Handbook" by Mark Duginske (this is possibly a revised version: here) and The Bandsaw Book by Lonnie Bird (here). A decent book is worth getting - makes for safer use of the saw apart from anything else.

 

[iajon69]

Momo

The main problem with blades for this machine are that they are thin gauge material which are notorious for easily breaking if too much tension is applied. If you change the blade to a medium .020 gauge blade then you will notice a big improvement - not just in the cutting performance but blade life as well.

The deflection issue will be different for OPJ and yourself because of the thin gauge material and the distance between the guides.
With a standard .025 gauge blade then I set the top guide about 5" from the table and then look for a side deflection of around 5mm either side of the blade - less for cutting hardwood or thick stock.
On a small machine with a .014 thin gauge blade distance between the top guide and table is smaller so the deflection should be less - around 2mm either side.

Hope this helps a little

Ian