Depth Gauge Rounding and Drive Link Deburring Wheels

[Philbert]

I have posted in a few threads that I typically use a 'ScotchBrite' type deburring wheel in a grinder to round over depth gauges after filing or grinding them, and to remove burrs on drive links, caused by chains jumping out of guide bar grooves. Some guys have other ways of doing these things, but the deburring wheels are fast, and leave a very smooth finish. The wheels I used were 6 or 8 inches in diameter, about 1 inch thick, and the consistency of hard felt.

Problem was that the hard, sharp, chain links were 'eating' these fairly expensive (typically $40 - $60) wheels. 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.

(My 'old' style 'convolute' deburring wheel)

With the help of a 3M technical representative, I tried out several similar-but-different products for these tasks, 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.

They are described as 'unitized wheels'; 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:

- 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).

- 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!

Philbert

 

[Philbert]

Line Up for Testing

The photos show the 5 different wheels I tried. 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 particular discs are speed rated from16,000 to 18,000 RPM, and with the right arbor can be used in a speed-compatible drill press, hand-held drill, die grinder, drill chuck on a bench motor (my choice), etc. Some are also available with a 'Rol-Loc' mount, in larger diameters for use on a bench grinder, etc.

The wheels are commonly used for weld blending, and are sold through industrial suppliers, 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.

Philbert

 

[Philbert]

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.

RESULTS

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 (but don't eliminate) 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. The 3M rep said that the coarser wheels will leave a smoother finish if used at a higher speed; will remove material faster; and will last longer. I would like to find a used, electric die grinder and try these again at higher speeds.

Summary: All of these wheels worked. If you were given a box of any of them for free, I would not throw them 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)
e.g.: Scotch-BriteTMDeburr & Finish PRO Unitized Wheel (UPC 048011-65004-3); 3×1⁄4 × 1⁄4; 18,100 RPM; Max 6-C-MED+; 40/box

Philbert

 

[huskihl]

I've only had to deburr drive links once. I picked up an old .404 x .063 or .080 solid nose Oregon bar and chain that looked like the chain came off and beat up a half dozen dl. I smoothed them out with a chain sharpening stone in a dremel.

As far as rakers, I've never done it this way, but tomorrow I'm gonna sharpen some chains and take down rakers from the gullet forward instead of filing down. Seems that it would be a win win situation by also creating more room for chips

 

[Philbert]

As far as rakers, I've never done it this way, but tomorrow I'm gonna sharpen some chains and take down rakers from the gullet forward instead of filing down. Seems that it would be a win win situation by also creating more room for chips

I am re-shaping the depth gauges to match the manufacturer's profile, and to eliminate any high spots that might dig in, after filing. Your description sounds like a more aggressive mod of the depth gauge design. It will be interesting to hear how that works.

Philbert

 

[CR888]

Very interesting stuff as per usual Philbert!! Your always finding the 'right' tool for the job at hand and the subject of drive link maitenence is not a popular subject around here. lt should be as many chain pics posted are always focussed on the 'perfect cutter' and rarely does any other part of the chain get discussed. Healthy drive tangs do more than drive chain, they are also responsible for good oiling. The shape and condition is important to a well running chain and even in normal use rim/spur sprockets can wear tangs changing their profile. Some chain makers suggest using a round chain file on the tangs to true them up. We all occaisionally experience a 'thrown chain' and the damge can render a chain not operable if not rectified. l have not seen a dedicated machine setup for this purpose and personally use my milwaukee variable speed die grinder with scotch brite pads to knock the rough edges off. Nice to know whats out there!

 

[ChoppyChoppy]

The burrs don't come off after running the chain in wood a cut or two?

 

[huskihl]

The burrs don't come off after running the chain in wood a cut or two?

The one I did had drive links peened over to 1.5 times the rail width. I'm guessing the chain jumped off and wouldn't turn around the bar so they junked it

 

[Hinerman]

FWIW, I just use a dremel tool with a grinding stone...

 

[Philbert]

As an update, I was able to find more of these wheels on eBay for reasonable prices.

The 6A-Medium wheels work well. I would also buy 7A-Medium or 8A-Medium wheels for tis application if they were a good deal.

Philbert

 

[Rx7man]

Have you tried the wheels with the abrasive embedded in the plastic? I posted pictures of them before

I think this one would work very well for what you're thinking
http://3mcollision.com/products/abr...adial-bristle-disc-07543-3-inch-80-grade.html

and for gasket removal, (unpainted) bar polishing, and general purpose flat stuff, this one is great, I get them for $10 Cdn for the 3"
http://3mcollision.com/products/abr...e-roloc-bristle-disc-07524-2-inch-coarse.html

the Yellow (80 grit) leaves a very nice finish on steel, and with a light touch is good on aluminum, though perhaps the White (120 grit) would be better suited.

They last a very long time!.. I was thinking of getting a 2" radial fingered one to clean up port edges, the would be 'nice' to the nikasil but still effective.

 

[Philbert]

Have you tried the wheels with the abrasive embedded in the plastic?

I have some of those - never tied them for this use. Have only used them for surface finishing, like removing rust, etc.

Interesting idea.

Philbert

 

[Rx7man]

The radial ones may work good.. I want to source some here, but they're a little hard to find

 

[Philbert]

3M products are usually good, and usually not inexpensive. Products like these are normally focused on industrial markets, so they often sell them in larger quantities, and often don't have good info for smaller users. If you can be somewhat flexible on the size/grit/style etc., and are patient, you can sometimes find them on eBay pretty reasonably as part of a close out lot.

Sometimes available reasonably through Amazon or Zoro Tools. Otherwise, typically expensive in small quantities through industrial supply vendors such as Grainger, Fastenal, Enco, MSC, etc.

http://multimedia.3m.com/mws/media/376017O/scotch-britetm-bristle-discs-and-brushes.PDF

Let us know if you try them out!

Philbert

 

[Rx7man]

Good PDF file.

One of the biggest benefits of the axial bristle disks I've been using is they just WILL NOT PLUG.. I had to do the head on a Cummins 5.9... Of course there's coolant splashed everywhere, used engine oil, and on the head side there was a HEAVY buildup of carbon on the valves, etc. That disk took everything off to a near factory finish regardless of what it had to take off... and it doesn't take any significant material off the head or deck either (magnesium is of course softer)

 

[Philbert]

Bump.

Philbert

 

[lambs]

FWIW, I just use a dremel tool with a grinding stone...

Me too. On the drive links only. I dress depth gauges with a flat file.

 

[Philbert]

Excuse for a yearly bump (BUMP)!

There are other methods for removing burrs on drive links. These threads mention a few ideas:
https://www.arboristsite.com/community/threads/deburing-drive-links.249436/

https://www.arboristsite.com/community/threads/junked-drive-links-replace-file-or-garbage.253336/

Franzen also sells a dedicated machine for this, which I might consider if I owned a sharpening business:
https://www.franzen-maschinen.de/en/products/sharpening-equipment/drivelink-deburrer/
https://www.stens.com/052-909-franzen-de-burr-attachment



@Homelite410 built a custom version of this a few years back.

The ScotchBrite wheels are a low tech solution that leave a very smooth finish on the drive links and depth gauges (if the right ones are used), and can be used on lots of different things. Another tool / consumable in the tool box.

Philbert

 

[CR888]

I use Rol-Lok™ 2" screw in pads to knock burrs after sharpening hedge trimmer blades. They are great for preparation too getting sap build up off them. 3M stuff is awesome but like Phil mentions you need to buy them in trade style bulk to get good prices. Buying a few of each coarseness is expensive compared to buying 50 of one type. Really good for cleaning up bar rust or burrs, even going over the rails leaves a silky smooth finish after filing. For depth gauge rounding/shaping I now use cheap Chinese sanding drums that cost a few bucks for a hundred with 1/8" mandrels. I think for 1000 in grits 80-600 I paid about $10aud. Got them for port work but there great for tons of stuff including sharpening edges.

 

[Philbert]

Roloc discs are a good idea. They come in a variety of diameters and grits, and could be a great way to reach the burred edges, using a flex shaft tool, Dremel, or right angled die grinder. I will have to try this!



Good to have options!

Philbert