blades breaking in clamp and jumping out of the clamp

[Heather McNeill]

Good afternoon. 
I have started to experience multiple incidents of blades jumping out of the lower clamp and more frequent incidents of breaking blades.

I use an old Hegner and cut 9mm thick MDF. I use Pebeco blades. I make jigsaw puzzles.

I have been doing this for about 5 years with little problem but just recently, jumping blades and breaking blades have got irritatingly frequent - such as 4 times within a couple of hours.

It's driving me nuts!

Any advice or suggestions would be appreciated.
Thank you, have a great weekend

Heather

[DWSudekum]

What it sounds like is that the screw that is pressing against the blade is getting polished or has become smooth for some reason.  Take your thumb screw out ... rough up the end a little and put it back.  That will probably help.

DW

[sawdust703]

If you've got blades breaking in the blade holder, & coming out of the holder, too, for that matter, could be several things. As already mentioned, the first thing to try is taking your thumb screws out, top & bottom, & rub them across a piece of 100 grit sandpaper until the face of the thumbscrews are flat again, & have straight lines from the sandpaper. This gives your thumbscrew grip against the blade when you increase tension. The next possibility could be over tensioning your blade. This will not only break blades, but pull them out of the holders, too. Your table could be out of alignment with the blade. Blade speed & material thickness could also be a possibility. Blade size could also be another possible cause. If you're trying to feed to fast, or push to hard against the blade, that'll pull the blade out of the holders, too, as well as break them. There could be several variables involved, it'll be a matter of process of elimination. Also, be sure your saw deck is waxed so the work piece can move easily. Just some ideas from experience. Hope it helps. Have fun & be safe!

[Heather McNeill]

Thank you both sawdust703 and DWSudekum for your helpful and supportive guidance, much appreciated.  Will take up your ideas.  Thanks for your time and effort.  Enjoy the rest of your weekend!

[Fordy]

Hi Heather

I also use that brand of blades. It is the only brand I can fine locally in Cape Town, South Africa, when available. The same happens with me. I have done the roughing up of the clamps, and it helps. I also learned it may be because of oil on the blades, so before using them, just wipe the clamped part of the blade with some alcohol spirits or so, to get rid of the oil.

As for the breaking, I am not sure about that one. After making changes to the tensions, pressures etc, I find it could even be that the breaking occurs after sharp turning. I know this is what the blades are supposed to do but I don't know what else to think.

I have a 2003 Hegner Multicut 2S

Lastly, I am looking to purchase new blades and I am not sure which exactly. I will post for comments on that.

All the best

Tyrone

[Danny]

Happy to meet you.  Danny here from Alabama USA.
I also use my  18" Hegner.  My experience of blades breaking at the point of
where the tightening screw makes contact with the blade is caused by OVER TIGHTENING.
Also the tip of that flat sides of the bracket needs a lil sanding.  Could be a burr present. 

This worked for my same problem long ago.........................Danny  :+}

[Heather McNeill]

Thanks for the advice guys, your expertise and helpfulness is appreciated.  I have also discovered that one of the retaining bits on the rear tensioner is very badly worn so shall be replacing that too.

[dirtrider73068]

Can use rubbing alcohol to clean the blades and clean the clamps. There could be build of oil from the blades as well sawdust or dirt letting them slip. Once in a while on my ex I take the thumb clamps out and clean them with rubbing alcohol. I also use a paper towel folded up to clean the set screw off as well. Can also sand the ends of the blades fold up a strip of sandpaper and pull the ends of the blades through it to rough of the ends.