Depth Gauges on a Grinder?

[Philbert]

Taking the time to radius the raker back to factory profile of rounded for the leading edge takes extra time and extra steps. A couple of strokes on the file to set the raker and sweep the file forward as you finish the stroke may be faster in this case because of the added steps.

It is an extra step.

Lately, after I hand file the height of the depth gauges, I have been taking the chain over to my bench grinder, and using a ScotchBrite finishing wheel to both shape the leading edge of the depth gauge (and humped tie strap, if the chain has one), and to polish the filed surface smooth. Takes about a second or two per link. This is also the way that I remove burrs on the drive links from chains that have jumped off the bar. Leaves a much smoother finish than a standard grinding wheel.

I am assuming that I would do the same thing if I ground the depth gauges.

( http://www.arboristsite.com/stickies/128518-113.htm#post3409670 Post #1682 )

Anybody grinding gullets and rakers with a similar set-up?

One of the reasons I posted this thread is that I had a large pile of chains (40+) that I had to work through, and it made me think about my process. I have cleaned gullets a few different ways, but here is my 'current' method (subject to change):

I sharpen all of the Left cutters, then all of the Right cutters without changing the grinder settings. Then I back off the chain stop on the vise about 1/2 a turn, and lower the depth stop about 3/4 of a turn. I lower wheel down into the gullet and clean it up with one tap. Do all of the Right gullets. Rotate the vise once more and do the Left gullets. It goes really fast, unless the gullets have been neglected for some time.

I am wondering if there is any reason one of the Harbor Freight cheapo grinders couldn't do a decent job on rakers?

There are several issues with the HF grinder, including quality, power, wheels, etc. Several A.S. members have posted that they have bought a used Northern Tool type grinder and dedicated it for rakers. Might find one on CL or at a garage sale for $50 -$60, which would be a better deal. Silvey makes a dedicated raker grinder, which could make sense for a production shop or large forestry company (my birthday is in September).

Silvey HDG-6 Depth Gauge Grinder | Silvey Chaingrinder - Medford Oregon

I once offered to submit to Oregon my improved procedure for their manual's treatment of depth gauge grinding, but they were not interested.

I once offered to re-write the Tecomec manual so that it was readable, in exchange for a grinder. I did not hear back from them.

Philbert

 

[Philbert]

Talking about improvements, I'd like to see progressive lines on the depth gauges that corresponds to lines on the tooth. If the tooth is ground back to the first of 3 lines the depth gauge needs to be lowered to the first of 3 lines.

I get what you are asking for. Some cutters have maximum wear lines engraved into both the top plate and depth gauge. I don't want to start a File-O-Plate discussion here, but I think that part of the reason for using a gauge tool is that some users may want more aggressive or less aggressive depth gauge settings depending upon the type of cutting they are doing, etc. I can choose to use a .025 or a .030 depth gauge tool, etc.

I think that it would also be hard to read a lot of fine lines after the chain is worn somewhat.

JMHO

Philbert

 

[Dan_IN_MN]

.......
I once offered to re-write the Tecomec manual so that it was readable, in exchange for a grinder. I did not hear back from them.

Philbert

What language did you write your letter to them in?:hmm3grin2orange:

 

[Philbert]

First Impression: C-

Maybe I am not getting something - which is why I am reaching out for input. Tried it today on 3 chains (your chains may differ - see notes below).

1) Profiling the wheel took a lot longer than I expected. Don't start this if you are in a hurry. I followed the Oregon manual and set the grinder head at 60 degrees, which gave me a flat of approximately .270 inches on my '1/4 inch' wheel (actual thickness .238 inches). I suppose that if you know the maximum length of any depth gauge that you will grind, and are good at trigonometry, you can set the grinder head at another angle and make better use of the wheel life.

2) Grinding took a lot longer than I expected. Granted, the chains I experimented on had long neglected depth gauges, with a lot of material that needed to be removed, but that is why I wanted to try this set up.

3) I 'blued' every depth gauge, even though I used the same, light 'tap-tap-tap' I use with the cutters. Not sure if I was impatient (see #2), if the depth gauges have less metal to dissipate the heat, if the metal is treated differently, etc. Even tried going around the chain a few times, taking a little more off each time.

4) I wanted to try Galde's approach of grinding all of the depth gauges inside-out, but realized that I could not, because the chain positioning dog only works with the chain in one direction, especially, if it is low-kick-back chain.

5) The first two chains I tried (STIHL) had the dreaded, triple-humped-tie-strap, low-kickback feature, which really interfered with grinding the depth gauge. I have been able to accommodate these when hand filing the depth gauges, so this was a surprise. These also blued very quickly. I gave up trying to also set these with the grinder (STIHL says to lower these on their chains when adjusting depth gauges, Oregon says not to lower the humped tie straps on their chains). I will have to file these separately, which takes away most of any advantage of grinding.

6) Finally got around the interference from the triple-humped-tie-straps by setting the vise angle at 35 degrees, and adjusting the positioning dog, so that the wheel ground the depth gauges at an angle but did not touch the tie straps. Did all of the Right side depth gauges, then rotated the vise and did all of the Left side depth gauges, just like grinding the cutters. Still blued all of the depth gauges.

7) The vise on my 511A does not hold the cutters as tightly as I would like, so pressing down on the depth gauge with the grinding wheel causes the cutter to tip forward.

8) I will still have to buff and profile the depth gauges and humped tie straps, just as I did with filing, so that is a toss up.

9) You still have to dress the wheel periodically to keep the flat shape and to expose new abrasive, similar to grinding cutters.

10) The third chain I tried (Oregon) had the humped-drive-link low-kickback feature, which caused much less interference with the wheel, but was still s-l-o-w, compared with filing. I stopped after just a few links.

Again, this was my first attempt, and I would love to learn ways to make this work better. Right now, hand filing works faster and better for me. Maybe grinding depth gauges works better with chains that are not low-kickback?

Philbert

 

[Grande Dog]

Howdy,
It's easy to "blue" your rakers especially when your removing more than what a normal sharpening would expose. The rakers hit your wheel in a small area, so it's easy to load the wheel to where you're rubbing them rather than grinding them. This can even be worse if your wheel isn't running true. You might not even feel the vibration but, it's real easy to be enough out of round that the raker doesn't stay in contact with the wheel for the complete revolution of the wheel. Once you start rubbing more than grinding, it'll get hot real quick.
Regards
Gregg

 

[Justsaws]

Philbert, if you are using a vitrified wheel it is a tough and in my opinion very slow going process to set height without severly overheating them.

If you can find a source for resin bonded wheel for your grinder that should be easier. The Foley branded wheels(rb) on my Foley grinder do a much better job the the Molab(v) wheels on the Windsor for setting dg height. I have not tried the Bell grinder wheels or grinder.

I use a FOP to do the setup on the grinder, if I have a bucket of chains to do.

 

[timmcat]

I use an old foley-belsaw sharpener with the 4" wheels to do my rakers, I peel the stickers off two of the stones at a time and stack them on the arbor so I can grind the goofy stihl and carlton bumper links in one swipe. I dont ever recall blueing a raker, not even the fat vanguard ones with that set-up, maybe its the smaller diameter, maybe its just a lower speed rig. I do grind them all from one direction even though its a reversable motor. When I do my own chains its with a file for both the cutter and the raker unless the chain hit a non wood spot in a tree.

 

[Justsaws]

The lower speed and the ability to slow down or even stop the Foley machines makes them easier to use without overheating the metal. The Foley wheels help a great deal as well.

 

[J.W Younger]

Rakers in my opinion are one of the most inportant parts of a good working chain. With a good file its pretty easy to keep em uniform. I don't use the progressive method myself just feel.

 

[Philbert]

It's easy to "blue" your rakers especially when your removing more than what a normal sharpening would expose. The rakers hit your wheel in a small area, so it's easy to load the wheel to where you're rubbing them rather than grinding them.

What's the answer GD? Dress the wheel more frequently? Just go painfully slow? What do production shops do or use?

If you can find a source for resin bonded wheel for your grinder that should be easier

Does anyone sell a resin bonded wheel that fits the Oregon type grinders?

I use a FOP to do the setup on the grinder, if I have a bucket of chains to do.

The set up was pretty easy - I just set the grinder head stop at the top of the depth gauge, then lowered it in small increments, until the first depth gauge lined up with the Oregon depth gauge tool.

Philbert

 

[Grande Dog]

Howdy,
If they're really in to it, a dedicated raker grinder is used. With them, the chain is moving as the wheel grinds. So you don't end up grinding on one spot, or track. Dressing more often, and keep the wheel true will help a bunch.
Regards
Gregg

 

[galde]

Here are a few more details on my techniques, which work very well for me. I made a reference mark in the near rail of the vise near the mid-point of the flat 1/4" wide wheel. I flip the chain dog back out of the way when I am grinding depth gauges, because I visually determine a range of where the tooth should be when the wheel comes down on the depth gauge. I use the reference mark to position each tooth, and I use the full width of the wheel, not just one spot, which is what the chain dog would do. I set the wheel at 90 degrees and the vise at 0 degrees. I use a dressing brick (1" square x 4" long) to clean and square the wheel before every chain. I lay the brick on the vise and bring the wheel down on it while sliding the brick back and forth to get a true flat wheel edge. A dirty chain (pitch, rust, oil, dirt, etc..) will quickly load up an abrasive wheel (also a file) so I use the USC to get the chains squeaky clean before sharpening. I never have problems with burning, even with heavy grinds. I use the pink vitrified wheels. When using the grinder I keep in my left hand a tool to firmly bottom out the link while clamping the vise and also to steady the tooth while grinding. The tool is like an awl with a slightly curved point. This eliminates any chatter and keeps the tooth rock-solid when the wheel makes contact. If the flat depth gauge grind leaves a noticable corner on the leading edge I use a cut-off disc in a Dremel to round off the corner. This takes me 1 1/2 minutes, typically, on a 72-link chain. My chain grinder sees most of its use on depth gauges, since I prefer filing for most sharpening jobs since I made a good filing vise.

 

[lambs]

This is a good discussion guys. I've been looking for a way to better grind the depth gauges; I get some variation between left and right sides, so I like the idea of reversing the chain direction. I've also wondered if the vise tilt feature would help ensure consistency but have not experimented with that.

This will seem ridiculous to some, but I have an old bar set up in my bench vise, leveled at the center of the vise with the help of a digital angle finder. I grind cutters using my Oregon 511a, then move the chain to the leveled bar and check the "drop" from the cutter to the depth gauge in degrees again using the DAF. I'll file one depth gauge by hand until I get about 6 degrees of drop (stock Stihl is about 4.25 degrees by comparison), then do the same to a cutter on the other side. I mark the two cutters with a sharpie so I know which ones I set, then move the chain over to the NT knockoff 511a grinder and index the wheel to the depth gauges that I did by hand, and grind all on each side, then index to the other side and continue. I'm pretty happy with the results. If one side of cutters needs to be ground back more than the other, this compensates for that by making sure both sides are still taking the same amount of bite.

I don't take any credit for thinking this up; there's a great thread from a couple years' ago with a long discussion about the FOP and whether or not it resulted in a true progressive depth gauge adjustment. That's where I learned about using the degree of drop instead of the amount of drop, which standard depth gauge adjustment gauges use.

 

[Justsaws]

The thickest grinding wheel for the 511 that I am seeing listed from Total in resinoid is 4.7mm., 145mm x 22mm x 4.7mm.

They discribe resinoid as "Softer, low-resistance wheel. Prevents cutter burning." They do not however list a 6mm depth gauge in resiniod for the 511.

It is availible for both Bell and Foley grinders but the arbors are too small for the 511.

4.7mm is 3/16", so 1/16" or 1.3mm too thin, I might give it a try if I had a bucket of chain to do. Your call as to what you are seeing on the chains you are working on in terms of wheel thickness.

Try contacting some sponsors and see what they can find you.

Edit to add that they do list a 5" x 22mm x 5/16" Borazon wheel for the 511. No idea what it costs but it is listed.

 

[lambs]

You could get a CBN wheel in any dimension you'd like

There are apparently a few manufacturers in the US that can make a cyclone type wheel from a steel blank with the edge coated in CBN. They'll make any size you want. I have one for my 3/8 pitch chain and my 511a pulls it just fine. You can always blue a cutter if you don't pay attention, but the cut outs in the wheel and the resulting breeze greatly reduce that risk.

It's not an especially cheap solution, but you get a wheel that also never needs to be dressed, will probably grind 1500 chains, and can be sent back and recoated when the finish finally wears down. If you routinely sharpen a lot of chain in the same pitch, it's a good option.

 

[galde]

Speaking of Borazon -- I got a 3/16 Borazon (cubic boron nitride) wheel and use it when I have a badly rocked-out chain, where a large part of the tooth has to be ground back to remove the damage. It does a great job of quickly eating away a lot of metal without significant heat buildup. The teeth never get too hot to touch, even with fast grinds. The downside is the roughness of the final finish. Since the wheel keeps a perfect shape, the resulting gullet needs only a stroke or two with a file to get an ideal final gullet and cutting edge. I would like to have mounted Borazon wheels for my Dremel grinder that I use in a drill press to grind depth gauges and safety chains for carving and safe boring. The rough finish wouldn't be a problem on the depth gauges or safety links if the grooves were lengthwise instead of crosswise.

 

[Philbert]

Well, I cleaned up the burnt depth gauges and tie straps on my 'test chains' on my bench grinder with a conventional grinding wheel and a 3M ScotchBrite wheel. Those are going to be a couple of really aggressive cutting, low-kickback chains!

Here are a few more details on my techniques, which work very well for me. . . . My chain grinder sees most of its use on depth gauges, since I prefer filing for most sharpening jobs since I made a good filing vise.

Maybe I need to come down to TN and watch you - I might see something that I am missing!

I cleaned all of these chains and dressed the wheel the way you described. It was the Oregon wheel that came with the grinder. Burnt the very first depth gauge. Adjusted the chain stop so that I was using different parts of the wheel for different cutters, so that I would use the wheel evenly. Dressed the wheel again when it looked dirty. Same thing. Right now, I am going to file the depth gauges on the rest of these chains, until I figure out what I am doing wrong.

there's a great thread from a couple years' ago with a long discussion about the FOP and whether or not it resulted in a true progressive depth gauge adjustment. That's where I learned about using the degree of drop instead of the amount of drop, which standard depth gauge adjustment gauges use.

Link to that thread: http://www.arboristsite.com/chain-sharpening/114624.htm

What type of wheel are you using Lambs?

The thickest grinding wheel for the 511 that I am seeing listed from Total in resinoid is 4.7mm., 145mm x 22mm x 4.7mm.

http://www.tiltonequipment.com/files/9912/9225/8029/grinding_wheels.pdf

Anybody know if any site sponsors carry these? Anybody use them?

I got a 3/16 Borazon (cubic boron nitride) wheel . . . It does a great job of quickly eating away a lot of metal without significant heat buildup. . . . .The downside is the roughness of the final finish.

Thanks for all the input.

Philbert

 

[Steve NW WI]

Phil, Tilton is the Jonsered distributor around here. You could likely get any decent J-red dealer to order em for you.

 

[Philbert]

You could likely get any decent J-red dealer to order em for you.

Thanks Steve. I think that I have to figure out the technique part first. Other guys seem to be able to do this with an 'ordinary' stone.
I am thinking that the amount of metal that I had to remove, and the humped tie straps or drive links, added a little to my problem.
Right now, filing is faster and easier, even if I am not getting them as exact as the grinder would.

But if people have tried the resinoid wheels, or have been able to grind these same types of chains without problems, I would still like to hear from them.

Philbert

 

[galde]

I forgot to comment in my previous post on the safety or bumper links. If you are hitting the bumper or safety links when grinding depth gauges, that means they are higher than the final depth gauge height, and thus must be lowered at least to the depth gauge height. The triple humped tie straps with the rooster tail will not let the chain get a bite on the bar tip once the teeth are ground back somewhat. On well worn chains of this type I usually just grind the bumper stuff down to make a non-safety chain. Many here dislike these chains because of poor chip clearance and slower cutting, but with the right grind on the tails of the bumper links they make excellent chains for carving (not for dime or quarter tip bars, though) and boring. The newer style chains with the ramped safety drive link that sits alongside the depth gauge on the flat of the bar but extends forward of the depth gauge on the bar tip have good chip clearance and anti-kickback function, but that thick, hard piece of steel is much harder to file or grind than the actual depth gauge. Here is where I would like a flat CBN wheel.