Chip Clearance, what is it?

rogue60 · Apr 8, 2018

Think of it like the old pencil sharpeners the ones with the little box to catch the shavings if the little box was packed hard full of shavings it was hard to sharpen the pencil. Now empty it and its easy to sharpen the pencil thats chip clearance.
Lots of tricks to getting more chip clearance with a saw chain and many hrs go into modify them basically the more room for the chips to be out of the way of the cutter doing its work uninpeded the better the faster it will cut along with other mods.
There is lots more to it than just chip clearance modding a chain but its an important one if the goal is a faster cutting chain.

rogue60 · Apr 8, 2018

Terry Syd said:
Thanks guys, if I ever run into the 'chip clearance' phenomena, then I will know what to do to fix it.

Its a racing chain thing nothing to stress about, if it happens in the real word and the chain binds up in the cut from chips just pull the saw out of the cut give it a few revs to clear and problem solved. You can feel it happening in the cut anyway just lift a little you will feel it clear.

Wilhelm · Apr 8, 2018

rogue60 said:
Think of it like the old pencil sharpeners the ones with the little box to catch the shavings if the little box was packed hard full of shavings it was hard to sharpen the pencil. Now empty it and its easy to sharpen the pencil thats chip clearance.
Lots of tricks to getting more chip clearance with a saw chain and many hrs go into modify them basically the more room for the chips to be out of the way of the cutter doing its work uninpeded the better the faster it will cut along with other mods.
There is lots more to it than just chip clearance modding a chain but its an important one if the goal is a faster cutting chain.

I like that comparison!

Terry Syd · Apr 8, 2018

It appears from some of the individual definitions of 'chip clearance' that I've already run into the problem. I can remember a moist punky log that I cut with an 18" bar that wasn't even fully buried in the wood. The wet sawdust dragged the power down and I had to keep clearing the bar and chain. - I don't think using a different chain would have helped.

When I shifted over to another dry log, the problem went away. IMO that was a problem related to the log I was cutting. It wasn't an inherent problem with the chain design.

I suppose there are limits to what can be done to design a chain for all conditions.

Al Smith · Dec 31, 2019

Art Martin had an interesting method of building a race chain. Instead of the normal cutter-space- cutter it was cutter- cutter-space,cutter cutter space .It was 1/2" chisel that had been thinned .I've got a picture on one of my hard drives .I suppose a similar method could be used on smaller chain which is highly unlikely I would do .

Wonkydonkey · Dec 31, 2019

In my limited experience, when cutting and using the dawgs. I’ve found there was a sweet spot, with engine speed and chips flying, to much pulling up on the rear handle slows the cutting and when released, the was a whole load of chips need clearing before the chain begins to cut.
However if not using the dawgs and holding the back of the bar up abit out of the wood, there’s some place for the chips to go. Every few few seconds while still holding the front of the bar in the wood if you dip the back of the bar in the chips that are in the kerf, a load gets kicked out and your still cutting.
Having said this every now and then, you also while chip clearing you need to eat a bit of wood at the back of the bar.. so you can maintain the cutting angle at the front

I hope this makes sense...

Wilhelm · Dec 31, 2019

I will post chip clearance issue pictures, but not tonight.

One and a half hours for me, Happy New Year guys!

Terry Syd · Dec 31, 2019

Over here in Oz it was 8 1/2 hours ago. - Doesn't look any different from 2019...

Wonkydonkey · Dec 31, 2019

I’ve got another 2hr & 5mins to go..... and it will still be dark,, so no change there then

But when I wake………it will feel just the next day

00wyk · Jan 1, 2020

Terry Syd said:
Over here in Oz it was 8 1/2 hours ago. - Doesn't look any different from 2019...

Hopefully less of your country is on fire now?

Not a race saw, but you can see the clutch cover loading up with chips:

Terry Syd · Jan 1, 2020

Thankfully (?) our area got burnt out in November. Things have quieted down since then and you can see the sky. Here's an area further south of me that is having some problems.

https://www.sott.net/article/426565...wildfire-turning-skies-RED-and-raining-embers

Deets066 · Jan 1, 2020

watch the chip flow on the down cut

Deets066 · Jan 1, 2020

Now on this one with a good chain and modded cover

rogue60 · Jan 1, 2020

00wyk said:
Hopefully less of your country is on fire now?

Not a race saw, but you can see the clutch cover loading up with chips:

We are in a bad way across the country it's so dry the on going drought means a lot of towns are almost out of water makes fighting fires hard with little to no water my town is out of water they are trucking in water. The end of summer can't come fast enough I don't know how the thousands of fire fighters are still going they haven't stopped fighting fires for months it's just been fire after fire the only thing that will put most the fires out is rain and there is none coming for the foreseeable future.

Wilhelm · Jan 1, 2020

Full House 3/8" Oregon EXL, 72 teeth on a 72DL loop - chip clearance issue is obvious.
The amount of chips couldn't get carried out of the cut so they compressed and made their way sideways up the bar sides, chain and bar binding was the result.

I hit the kill switch at WOT mid cut, I wouldn't wanna do this repeatedly though.
The log was turkey oak, very dense wood species.

Chain is courtesy of Jason @jmester , hopefully I will find more time to play with it.
Full House still intrigues me, there is something about it that triggers my interest.

andyshine77 · Jan 1, 2020

I believe the chips on the side are carried there from the chain as it goes around the top of the bar. That's my guess anyway.

Also the teeth act as the takers, so less teeth means less chip clearing, although less teeth equals less chips.

This is always an interesting topic.[emoji111]

huskyboy · Jan 1, 2020

I found that metal chain catchers inhibit chip clearance. Especially noodling. Fitting a roller catch helps hugely, it sits a little lower. Not to mention, it also keeps thrown chain from getting dinged up like a metal catch.

Ketchup · Jan 1, 2020

It’s funny to see so much discussion of chain shape here when chip clearance for me is mostly about clearing the clutch area.

My chip clearance issues are usually wood related. Sticky, gummy, or cross fiber wood tends to jam far easier, as do cuts through root flares and complex junctions. Noodles seem to clear okay as long as you keep the dawgs off the log.

I find having razor sharp gullets helps keep the chain moving through the chip bits that fall along the side and also prevents long fiber stands dragging on the side of the tooth. A smooth cut wall really seems to help.

Other mechanical clearance things I notice are the geometry and volume of the space behind and above the sprocket, the chain catcher, the stickiness of the bar oil, tightness of drive tooth fit in the bar gauge (slop is bad) and chips getting between the sprocket and drive teeth.

But I guess you guys are mostly talking about race saws with little or no clutch cover, running short bars in dry cants.

I don’t know much about that, but I do have chip jam problems. My personal chip clearance issues are mostly in Cottonwood cutting large stumps flush to ground and making 24”+ blocking cuts in the tree. Pulling the saw out to of the cut to clear chips is tiring and effects production.

Although a lot of the discussion above is race related, it all applies for my own race against the Crane ($225/hr). I love all the great discussion on this site! You guys really keep me thinking!

Wilhelm · Jan 1, 2020

For me clutch cover chip clearance is rarely an issue, it only matters when noodling and I rarely noodle firewood.
Generally a well designed chainsaw should show little to no clutch cover clearance related issues.

On the other hand, in cut chip clearance when bucking is a thing that needs be considered and I am not talking race chain.
Usually chip clearance issues go hand in hand with longer bars, which is one of the reasons why there are semi-skip and skip chains.

I only posted the Full House chain pictures because that particular chain sequence will show chip clearance related issues on shorter bars in smaller diameter wood.

Ketchup · Jan 1, 2020

Wilhelm said:
For me clutch cover chip clearance is rarely an issue, it only matters when noodling and I rarely noodle firewood.
Generally a well designed chainsaw should show little to no clutch cover clearance related issues.

Until this year I would have said the same thing. Recently I have had chips packed behind clutch covers so bad I had to send the saw down. The main saws I experience it with are 372xp and MS362. It happens when the saw is on its side, relatively deep in the cut. Usually in green cottonwood, ash or elm. I’m strongly considering a high output cover for my 372s.

Chip Clearance, what is it?

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