Calling Out The Internet BS

[Vintage Engine Repairs]

I remember when I first started to learn about small engine repair it was a minefield of contradictory info, hopefully this video helps to dispel the many small engine myths going around for those new to the hobby!

 

[hacskaroly]

I had many people coming up to me at work wanting to buy a new chainsaw bar because of the bluing streak along the rails being told they had burnt it up...had to tell them that was just the heat treating that gets painted over and only shows when the paint starts coming off. Now if the rails were lop-sided or burring out to badly or gouged in spots, the I might recommend a new bar if those things could not be corrected.

 

[066 redeye]

Same as bluing on the crank.

 

[JRHAWK9]

Same as bluing on the crank.

As in they are -NOT- blued from any kind of heat treating.

 

[IffykidMn]

What is the difference in bar rail hardness between a painted bar and a natural finish bar?

Asking the same question in a different manner.

Why are the rails on a painted bar heat treated and not a natural finished bar?

 

[Jethro 2t sniffer]

What is the difference in bar rail hardness between a painted bar and a natural finish bar?

Asking the same question in a different manner.

Why are the rails on a painted bar heat treated and not a natural finished bar?

Just polished off I guess same as any heat mark.

 

[066 redeye]

Well I am running a few saws with f##%&ed cranks then.
Bluing on the crank but not on bearings or pin.
Still running after about 5 years so will see if they last.
Not disputing the fact just my observation.

 

[Creaky limb tree care]

Well I am running a few saws with f##%&ed cranks then.
Bluing on the crank but not on bearings or pin.
Still running after about 5 years so will see if they last.
Not disputing the fact just my observation.

Me too! Can anyone explain how does a crankshaft get to a temperature of between 5 or 600° Fahrenheit (temp required for bluing) without crankcase detonation ?

 

[Philbert]

Why are the rails on a painted bar heat treated and not a natural finished bar?

Not sure that’s accurate.

Laminated bars are a 3-piece sandwich, which are typically spot welded together.

Solid bars are milled from a single, steel, blank.

Both need to be heat treated: you want the rails to hold up to wear, but don’t want the bar to be brittle.

Probably different alloys, and maybe different heat treat methods?

When I saw laminated bars being made, they used electric resistance heating. Quick. Blued rim. Like the teeth on some hand saws at home centers.

Maybe they polish off the blue on the more expensive, solid bars? Would be an extra step / extra cost on a powder-coated bar.

Philbert

 

[IffykidMn]

Not sure that’s accurate.

Laminated bars are a 3-piece sandwich, which are typically spot welded together.

Solid bars are milled from a single, steel, blank.

Both need to be heat treated: you want the rails to hold up to wear, but don’t want the bar to be brittle.

Probably different alloys, and maybe different heat treat methods?

When I saw laminated bars being made, they used electric resistance heating. Quick. Blued rim. Like the teeth on some hand saws at home centers.

Maybe they polish off the blue on the more expensive, solid bars? Would be an extra step / extra cost on a powder-coated bar.

Philbert

Perhaps my use of the natural finish bars was to general in nature.

The Sugihara light and Huskie tough light bars as well as a Tsumaura light bars do not appear to have the blue heat coloring on the rails which raised the question are they heat treated or different process? did not think one could polish enough to remove the bluing from heat treating.

 

[Philbert]

. . . did not think one could polish enough to remove the bluing from heat treating.

Did a quick test on a ‘scrap’ bar:

Blue line came right off with a little buffing, using 320 grit, ‘Wet-or-Dry’ sandpaper.

Also came off with ‘Bar Keeper’s Friend cleanser (but messier).

Philbert

 

[Woodtroll]

Did a quick test on a ‘scrap’ bar:

Blue line came right off with a little buffing, using 320 grit, ‘Wet-or-Dry’ sandpaper.

Also came off with ‘Bar Keeper’s Friend cleanser (but messier).

Philbert

Yep, it's just surface coloration. Even color case hardening on firearms, which is a much more involved process that penetrates somewhat deeper, is pretty fragile (as far as retaining the desirable color, anyway).

 

[EFSM]

Did a quick test on a ‘scrap’ bar:

Blue line came right off with a little buffing, using 320 grit, ‘Wet-or-Dry’ sandpaper.

Also came off with ‘Bar Keeper’s Friend cleanser (but messier).

Philbert

Interesting. I would have bet a fair amount on that bluing being deeper, but I guess it’s just oxidation color?

 

[Philbert]

Interesting. I would have bet a fair amount on that bluing being deeper, but I guess it’s just oxidation color?

As @Woodtroll suggested, it might vary with different products, treatment methods, etc.

This was a ‘quick-and-(not too) dirty’ test on one bar.

I assume that on an unpainted, or clear coat bar, it gets passed under some polishing rollers to make it pretty, with a uniform scratch pattern, etc.

But there also might be other heat treatments used that don’t create the bluing.

Maybe somebody with authoritative knowledge will chime in.

Philbert

 

[sawmikaze]

I remember when I first started to learn about small engine repair it was a minefield of contradictory info, hopefully this video helps to dispel the many small engine myths going around for those new to the hobby!

You could headline for Masterpiece Theater.

 

[legdelimber]

Spent a few months in a metal furniture shop.
Most material went through a wet sander.
Basically a conveyor belt running underneath a vertical belt sander.
Recirculating coolant and the belt contact was where the belt goes around the roller.
Not against a flat platen like freehand stuff.

Feed the stock through much like feeding a wood planer.
There is an adjustment for the space between the sanding belt and the conveyor.
You needed to keep the wear spread out across the belt(s).
An lazy operator who fed everything down the middle would wear the belt out in the middle could cause damage or injuries.
If you had the gap/pressure set based on the worn area of a belt and then fed a part off to the side (where the belt grit was not worn down)
It would grab and throw the stock like a damned harpoon.
Tended to tear up the pressure rollers also.

Never quite understood why people called it a "brushed finish" though.