Making new lower Chip Breaker for Pistorius

Create a Post
Larry Peterson

Larry Peterson

SPFG, Supreme Picture Framing God
Resource Provider
Joined
Apr 8, 2003
Posts
11,619
Loc
Wilkes-Barre, PA
I made a new lower chip breaker for my Pistorious EMN-12 today and thought that I would post some pics in case anyone else is interested in making a new one for theirs.

First a couple of pics of the existing lower chip breaker. My saw is about 20 years old and this might be the original breaker.

cb1.jpg


cb2.jpg


The original breaker is 2" wide and 2" deep. It's cut from a round piece of stock but doesn't need to be round. My replacement isn't round.

Next I glued up a couple of pieces of oak for the new breaker. The two pieces were 2" wide and 1 1/2" thick and 3/4" thick giving me a final piece 2" wide and 2 1/4" thick. The thickness isn't important except for the bolt that holds it in place. Rather than cut down the piece to 2" thick, I just used a longer bolt.

cb3.jpg

cb4.jpg


One of the reasons I used two pieces rather than a single block is that it made it easier to make the "shelf" at the top. The other reason is that this is what I had in the shop. You can't buy a 2" piece of hardwood stock around here so I would have had to buy it online. The 3/4" thick piece doesn't even need to be hardwood as that part never comes in contact with the blades.

Next I had to cut out a notch so it would fit.

cb5.jpg


On to the drill press to drill the upper end of the notch that the bolt will go through.

cb6.jpg


And then to the band saw to complete the notch

cb7.jpg


And the final installed breaker. I also reversed the upper block and made my first cut.

cb8.jpg


I made some adjustments after taking this pic to bring the breaker flush with the leading and trailing edges of the saw ledge.

TaDa:thumbsup:
 
Thanks Larry! Making my own from know on will save me big bucks. Great post.

But the last photo confuses me.

"And the final installed breaker. I also reversed the upper block and made my first cut." ??????

Can you clarify for me please.

Tom
 
Tommy P said:
Thanks Larry! Making my own from know on will save me big bucks. Great post.

But the last photo confuses me.

"And the final installed breaker. I also reversed the upper block and made my first cut." ??????

Can you clarify for me please.

Tom
Click to expand...

There are two chip breakers; an upper and a lower. The upper chip breaker is a separate piece of Phenolic. It can be reversed after the front side has too much wear. It wasn't part of what I made and I decided to reverse it while installing the lower chip breaker.

There was another thread that talked more about this at http://www.thegrumble.com/showthread.php?54358-Now-that-Pistorius-is-out-of-business...&highlight=pistorius
 
hangupsgallery said:
Studied the photos thoroughly, still can't figure out what a CHIP BREAKER is or what it does. :nuts:

(Been running chop saws for almost 40 years)
Click to expand...

The chip breakers have a single purpose; to reduce or eliminate tear out. Tear out can be a real problem for framers especially with gessoed mouldings.

Tear out is the splintering that can occur at the end of a wood cut. The image below shows some examples of tear out.

tearout.jpg


One way to reduce or eliminate tear out is to provide a backing that is placed right up against what is being cut. The saw will cut through the piece being cut and the backing. The backing will eliminate or reduce tear out.

One the Pistorius saws they use two chip breakers to prevent tear out. The upper chip breaker works to reduce tear out on the side of the moulding. The lower chip breaker works to reduce tear out on the bottom of the moulding.

Over time, the slots cut into the chip breakers will widen and reduce the effectiveness of the breakers so they need occasional replacement. The thread mentioned in my last post talked about getting these breakers now that Pistorius has gone under. Some vendors will be continuing to carry the chip breakers but they are far too expensive.

The previous thread talked about making your own upper breaker. It is simple since it is just a single square piece. The lower breaker is more complicated and some may not be inclined to try to make their own. The purpose of this thread is to give some more info for those who would like to make their own.
 
Oh Larry, now I'm really puzzled. What is an upper chip breaker? I have the lower one but not aware of an "upper" and where it goes.

Realize that I bought my saw out of 7 year garage storage and it was pretty bare bones when I got it. I added the lower chip breaker (from Pistorious for $100 after advice here) and it has helped greatly. But an upper? Sounds like something my saw should have.

Please elaborate.

Thanks
 
Thanks Larry.... I always knew there were ways to make them instead of paying top dollar for replacements. I guess the best material to use is a hardwood to prevent the block from splintering. Question.... How many replacements did you make so you could just pop one in when needed? :D
 
hangupsgallery said:
Larry
In your last photo, our we looking at the saw from the operators position? And if so, then the chip breaker is in the vertical position? This looks like the saw runs backwards to most chop saws. Sorry, not seeing how this works.
Click to expand...

The photo is from the rear of the saw. In that photo you will see both chip breakers.

The lower breaker is the lighter colored piece of wood that I just made. When the moulding slides through the saw, the lower breaker is under the moulding.

The upper breaker is the darker piece of wood with the two groves. The side of the moulding sits against the upper breaker. The upper breaker is factory made. If you look closely you can see that I have reversed it.

The two breakers provide an "L" shaped surface that the side and bottom of the moulding rest against when being cut.

The two breakers prevent/reduce tear out from the side of the moulding (upper breaker) and the bottom of the moulding (lower breaker).
 
TopGun said:
Question.... How many replacements did you make so you could just pop one in when needed? :D
Click to expand...

Just the one for now. The upper block is a simple block that is (I'm not at the shop - but roughly) 2" x2" x 1/2". I just reversed the factory one I have so it should be good to go for a while. When I do replace it, I will probably make a dozen or so of this one as it is simple to make.

I only made one of the lower breaker as it was my first time attempting this and I designed/made the block iteratively. Now that I know what to make it, I will probably make several the next time I need one.
 
Speak of the devil

I just got the monthly special email from Decor and they have the upper and lower chip breakers in the monthly flyer.

You can see both a little better than in my pictures.

cb9.jpg


For those prices I will continue to make my own.
 
Create a Post
Back
Top