Author Topic: Depth Gauge Rounding and Drive Link Deburring Wheels  (Read 626 times)

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Offline Philbert

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Depth Gauge Rounding and Drive Link Deburring Wheels
« on: August 14, 2015, 02:54:51 pm »
Chain manufacturers recommend rounding over the depth gauge on each cutter, to match the original factory profile, after adjusting their height.  The sharp point left where the flat, filed area meets the rounded portion can dig in and lift the cutter when it rotates in the cut.

A lot of guys just don't do this. Those that do, often use the same file that they used to file the depth gauge.  Some use a bench grinder. Some use a Dremel tool.

Similarly, when a chain jumps out of the guide bar groove, burrs are formed on the drive links where the sprocket keeps hitting them.  These burrs can keep the drive links from fitting back into the groove, and must be removed. Some guys file these off.  Some guys use a bench grinder.  Some use a Dremel. Some guys flatten the burrs with a ball-peen hammer on an improvised anvil.

For many years I used a large, 'Scotch-Brite' brand deburring wheel for both of these tasks.  It works fast, and leaves a smooth, polished finish.  The wheels I used were 6 or 8 inches in diameter; 1/2 to 1 inches thick; mounted on a bench grinder or motor shaft; and about the consistency of hard, dense felt.

One problem was that the sharp depth gauge and drive link corners would just 'eat' these somewhat expensive wheels (typically $40 - $60).  While they would last 'forever' when cleaning rust off garage sale finds, etc., the chains made quick work of them.

The other challenge was polishing these fairly small parts without hitting my newly sharpened cutter edges, hitting the tie straps, or unintentionally re-shaping the drive link profile.  I decided to try a new approach.


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Offline Philbert

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Smaller Wheels - Different Types
« Reply #1 on: August 14, 2015, 02:57:00 pm »
Companies like 3M, Norton, etc., make a wide range of abrasive products, with many variations, to meet many task requirements.  While this is great for meeting the customer's needs, it can be overwhelming to identify the 'best' product for a specific application.

With the help of a 3M technical representative, I'm now trying some smaller, similar-but-different products for depth gauge rounding and drive link deburring, and promised to share the results with others, to make it simpler for them.

I am starting with smaller diameter, thinner wheels, which will 'fit' better into these chain locations. These are mostly 3-inch diameter by 1/4-inch thick wheels, that fit onto 1/4-inch or 3/8-inch mandrels.  Of course, other sizes (2-inch diameter, 1/8-inch thick, etc.) will also work, but these appear to be more commonly available, and to be a better cost/value/size choice.

Each is described as a 'unitized wheel'; essentially a compressed ScotchBrite-like product that can be rotated in either direction - *not all can*.  In addition to size and mounting type, they vary in a few ways:

- Density / Hardness: Designated by number (2 - 11), a softer wheel (lower number) will conform easier to a contoured surface than a harder wheel (higher number), which will last longer.

- Mineral / Abrasive type: 'A' aluminum oxide, 'S' silicon carbide, 'C' ceramic.

- Grade / Coarseness: Might be specified by grit size (like sandpaper), or in qualitative terms ('VF' very fine, 'F' fine, 'M' medium, 'C' coarse, 'XC' extra coarse, etc.).

This means LOTS of combinations and choices! (select 'Virtual Big Book', enter page 1043)


Offline Philbert

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Line Up for Testing
« Reply #2 on: August 14, 2015, 02:58:24 pm »
The photos show the 5 different wheels I am going to try, along with 5 different arbors! 

From left to right (density, mineral, grade): 9-C-XCoarse; 9-C-Coarse; 5-A- Fine; 6-C-Medium; 2-S-Fine. The other markings are 3M marketing/application terms.

These discs have either 1/4-inch or 3/8-inch ID mounting holes, and I have them mounted on 1/4-diameter arbors which can fit into: a drill press; hand-held drill; die grinder; drill chuck on a bench motor (my choice). Some are also available with a 'Rol-Loc' mount, in larger diameters for use on a bench grinder, etc.

These particular discs are speed rated from16,000 to 18,000 RPM, and need to be used on speed-compatible arbors and tools - check what you have/use.

They are commonly used for weld blending, and are sold through industrial suppliers (Grainger, Fastenal, Enco, MSC Direct, etc.), as well as welding supply houses and Internet vendors.  Cost seems to run between about $5 - $12 each wheel (without the arbor), depending on the size, type, vendor, and quantity: some need to be ordered in boxes of 40 to get the best price, so maybe find some friends to split a box, or be nice to a welder.


Offline Cut4fun .

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #3 on: August 14, 2015, 02:59:28 pm »
Good thread and Thanks for time doing so.
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Online srcarr52

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #4 on: August 14, 2015, 05:07:35 pm »
I use a 2" angle grinder with a sanding wheel (120 grit) to deburr drive link. I used to use an air grinder but now I have a 2" grinder that fits on my foredom cable drive so I can control the speed with a foot pedal.

Offline Philbert

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #5 on: August 14, 2015, 05:48:20 pm »
I use a 2" angle grinder with a sanding wheel (120 grit) to deburr drive link.

That sounds like a good idea too!  You are using the flat face of a sanding disc, versus me using the edge of a wheel, correct?  I have a right angle attachment for my Dremel tool that I could try. For some reason I only thought of, and seen, using the Dremel stones  for doing this.

Do you also use these discs to round the depth gauges?



Offline 3000 FPS

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #6 on: August 14, 2015, 07:52:18 pm »
I use a small air grinder with a fine 2" disc sander or file for deburring drive links.

For the depth gauge I have a Tecomec chain grinder that I use and dedicated to only doing the rakers.   I then took one of the wheels and shaped it to the raker and found it to give the rounded shape that I want and consistent height from raker to raker.   I  was using a dremel with a chain vise that I made but found the Tecomec to be faster and more accurate.   

I still use the dremel sometimes to thin the top part of the raker.
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Offline Old Iron Logging

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #7 on: August 16, 2015, 02:44:10 pm »
When we threw a chain at work, we just put it back on bar with about an inch of slack. Start saw and blip the throttle a couple of times. Burrs gone. No harm to bar or chain. If you try this method keep the chain tight enough not to bump the chain catcher.

Offline HolmenTree

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #8 on: August 17, 2015, 08:29:33 am »
Yup that's all I ever do too. Last time I used a file or a stone on a peened drive link was over 30 years ago when I threw the 5 ft chain on my 090 with its original spur sprocket drum. :D
Rounding off the leading edge of the depth gauge I use the same flat file that I lower them with. Then after a few hours of cutting in wood they get perfectly honed smooth with the perfect angle of approach matched to its cutter bit size.
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Offline Philbert

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Re: Depth Gauge Rounding and Drive Link Deburring Tools
« Reply #9 on: August 22, 2015, 08:21:55 pm »
Depth Gauge Rounding Test

Totally subjective, but systematic, testing of the 'unitized' blending / deburring / polishing wheels described above.

Test Parameters: Primary test subject was a STIHL 3/8, .050, 84 DL chain with bumper drive links. I had to lower the depth gauges quite a bit on this chain, so a lot of reshaping was needed on the depth gauges and low-kickback bumpers to round off the flat tops created by my 511A grinder. Lots of links to test.

Secondary test subjects were about 8, STIHL .325,  .063, 67 DL chains with either drive link bumpers or tie strap bumpers. These required mostly light rounding.

Wheel arbors were mounted in a drill chuck on 2 bench motors: 3450 and 1725 RPM.


Wheel Size: I really like the 3-inch diameter, 1/4-inch thick wheels for this task.  I had been using much larger format (6 and 8 inch diameter, and 1 inch thick), 'convolute' (softer, directional) wheels, because those were what I had.  These smaller wheels minimize the chance of hitting the freshly sharpened cutting edges, and easily reach any burrs on the drive links (not tried in this test).

Wheel Grade: Predictably, the coarser wheels removed material faster, but left a deeply scratched finish. The finer wheels removed material slower, but left a highly polished finish. 'Medium' to 'Medium +' seemed to be the best compromise for this purpose.

Wheel Density: Wheels in the '6' to '8' range seemed to work well shaping the depth gauges and bumpers with a minimum of wheel wear.

Abrasive Type: I didn't get to compare identical aluminum oxide ('A') and ceramic ('C') wheels side-by-side.

Speed: The 3450 RPM motor worked much better than the 1725 motor.  In addition to the higher speed of removal, the coarser wheels really chattered at the lower speed.  If using a slower motor, go with a finer abrasive grade.

Summary:  All of these wheels worked.  If you were given a box of any of them for free, I would not throw it out.  But if you are buying them, you might as well get the ones that work best.  I would choose 3 x 1/4 inch 'unitized' wheels with markings like:

6-A-Med, 6-C-Med+, 7-A-Med, 8-A-Med (availability will vary with manufacturer)



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