Sparks - how much is normal

[Kev]

Evening!

Have been setting up my new bandsaw today which has ceramic guides, so far so good, and got to the stage of doing a few test cuts only to be greeted by loads of sparks coming from the top rear guide. Panic ensues, turn off the machine did a bit of research and find its quite normal to get a few sparks. My question is what constitutes a few sparks. Have set the rear guide as would on my normal guides on my old machine so close but not in contact with blade unless some pressure is placed on the blade. There were sparks every time I pushed timber up against the blade. Do I need to allow more space (which I assume cannot be the answer as negates the point of it being there surely) or is it something you just get used to, does it get less as the guide 'Beds' in. Anyone using ceramic guides have any advice.

Thanks

Kev

 

[Fitzroy]

New blade always sparks for a bit on my bandsaw, then settles down. Mine has a carbide thrust bar.

 

[mikej460]

I'd be a bit concerned about sparks and sawdust

 

[Sandyn]

The only time I saw sparks from my bandsaw was when I set it up wrong. I don't have ceramic guides. There was a thread here, which may give some info.

 

[Terry - Somerset]

There are lots of bushcraft tips about how to start a fire with a broken plate and steel knife..

I assume the back of the blade when initially fitted is microscopically "rough" and will create sparks. I also assume that once "run in" both it and the blade guide become sufficiently smooth that sparking rarely if ever happens.

 

[Doug B]

I’ve found over the years that it’s the type of bearing set up that leads to sparks, particularly there orientation to the blade & whether they are actual bearings or solid discs.

 

[Kev]

I'd be a bit concerned about sparks and sawdust

That was my concern to be honest. It seems very counter intuitive. If you search ceramic guides and sparks it would seem to be a very normal issue - just seems very weird to me. Might try a different blade in the morning (just had Tuffsaws blades delivered) and see if that makes any difference.

 

[Richard_C]

Axminster do a wednesday workshop series, below. He is using a ceramic guide machine and about 6 minutes in says that a 1mm gap is about right. No sparks (but maybe they did loads of re-takes).



There are others in the series and I found them useful when starting out. I rarely get sparks now (did to start with) and there is a 'sweet spot' when you get the tension right and the gap right. Then its all about speed of feed, expect too much from the machine or go too fast with too fine a blade and you get sparks. I still get them off the side guides and sometimes the rear if I am over ambitious with curves, but after a bit I stopped worrying.

I'm fairly careful to keep extraction going and clear any build up of dust in the lower cabinet, and generally I stop work and switch everything powered off a few minutes before I walk away, whether thats the bandsaw, lathe or drill. Theres' always plenty of thinking and planning to do.

 

[Lefley]

No sparks. There should be a paper joint between everything when it is under zero load!

 

[Keith 66]

I have owned four bandsaws, A big wadkin two startrites & a Rexon. I still have the last Startrite & the little rexon.
All have roller guides. The earlier startrite had steel bearing blocks & thrust pin (cheap & shoddy cost cutting exercise) & i converted it to run coolblocks on the sides & roller at rear. That transformed it into a good machine. Rear bearing rollers tend to get their faces grooved if they stop rotating & then sparks are more common.
A tip i was taught years ago was when setting up a new blade to gently stone the arris of the back corners of the blade with an old oilstone laid on the table. This helps reduce sparking.

 

[Ttrees]

Depends on the job, the blade used, and how much beam tension it has, and what way you have your particular machine set up.
Has it got flat tires or crowned and how hard are you pushing it.
Guessing its at least a mid sized machine, as I haven't came across much folks using ceramic guides
on smaller ones.
Sounds possible you could improve matters.

Tom

 

[Nick.]

Hi Kev,
As has already been said, It's normal to get quite a few sparks from a new blade when under load until the back of the blade 'smooths' out.
It then gets a lot less sparky after you've used it a bit.
Ceramic thrust guide - I've always just pushed up to lightly touch the blade once the blade has found its running position and no issues, but it then comes into play to do its job when load is applied.
No need to move it backwards, as then it will not keep the blade straight.
Cheers, Nick

 

[Kev]

Hi Kev,
As has already been said, It's normal to get quite a few sparks from a new blade when under load until the back of the blade 'smooths' out.
It then gets a lot less sparky after you've used it a bit.
Ceramic thrust guide - I've always just pushed up to lightly touch the blade once the blade has found its running position and no issues, but it then comes into play to do its job when load is applied.
No need to move it backwards, as then it will not keep the blade straight.
Cheers, Nick

Thanks Nick,

Used it today and as you say now that the blade has bedded in a bit on the back edge the sparks have pretty much gone. Have left the thrust guide almost touching the back of the blade. I have to say the ceramic guides do seem quite impressive as you can get the tolerances very close to the blade.

kev

 

[Woody2Shoes]

I have owned four bandsaws, ......
A tip i was taught years ago was when setting up a new blade to gently stone the arris of the back corners of the blade with an old oilstone laid on the table. This helps reduce sparking.

+1 for this - I just use a metal file - it helps to reduce the risk of a) sparks, and b) scoring of the thrust bearing.

PS I thought this thread was going to be a rant about the cost of engaging the services of electricians!

 

[Kev]

PS I thought this thread was going to be a rant about the cost of engaging the services of electricians!

Give it Time!