Oregon grinder disc wear compensation adjustment, ideal adjustment ?

[JaIt]

Hi guys. Long time lurker, never bothered to post as I almost allways find what I need by searching myself but I thought this one might be an interesting one since I didn't find it in here with the level of detail I needed.
So basically I got an Oregon 520, I think the adjustment is similar in previous models and/or Tecomec ? Not sure... Anyway, I know how the adjustment is done, by loosing the screws on the bottom of the base and moving the vise assembly back/forwards.. But other than visually seeing it's out of whack how should one ideally line up things ? When setting up the disc initially the manual says the following, which I assume is when the disc is new and hence has the entire diameter: put a straight edge like a ruler on the vise and line it up with the guard securing screw (that holds the plastic arbor shield...), with the angles set to 0 on the vise and 90 on the arm. But again, this is for when the disc is new, what about when the disc is worn out what reference should we use ?
Scratching my head as i couldn't find it anywhere, of course one could do it visually, but as the disc wears out so will our chains be grinded slightly differently so probably not easy to check visually either until it's completely out of whack....
Cheers

 

[Philbert]

Welcome to A.S.!

That wheel wear adjustment is a nice feature. As I understand it, you check and adjust the vise position periodically, as the wheel wears, and the outer diameter changes. Of course, this means that you also need to check this adjustment if you swap between different wheels.

Some grinders have different adjustments for centering the wheel. Some do not have any. Since I use different grinders, I do a manual check* with each loop and and compensate as needed. The 520-120 grinder lets you do this a bit more precisely.

* I grind one side of the chain first (e.g. all the Left cutters); then grind one cutter on the other side (in this case a Right cutter). Hold a Left cutter back-to-back with the first Right cutter and visually compare. Make any adjustments as needed, then grind the rest of the Right cutters.



Philbert

 

[JaIt]

Thanks! Man, that's a lot of work, I'm guessing "any adjustments as needed" is to do with experience too... Makes me want to buy one of those CBN/ABN discs already... Anyone knows a good source in the EU ?

 

[Philbert]

Thanks! Man, that's a lot of work, I'm guessing "any adjustments as needed" is to do with experience too...

It might sound more involved that is really is: just becomes automatic. Like a lot of other skill sets; no different than 'measure twice, cut once', etc. Or inserting a wedge into a kerf 'just in case.'
You should not have to adjust for wheel wear until the amount of wear is significant, or unless your wheels are of very different sizes. Remember that most grinders do not even offer this feature and people still use them. It offers you a higher level of accuracy and consistency, if you want it.

Makes me want to buy one of those CBN/ABN discs already... Anyone knows a good source in the EU ?

I did not like the CBN wheels I tried as much as properly dressed, good quality, AO/vitrified wheels. I might be an outlier on this, and maybe other wheels work better? I did not think that the CBN ground much faster. It's true that they do not change size, and they generate less grinding dust. But, on the other hand, I can change the profile of my vitrified wheels if I want to for custom grinds / profiles, and I grind outside.

Philbert

 

[Mike Kunte]

Welcome to A.S.!

That wheel wear adjustment is a nice feature. As I understand it, you check and adjust the vise position periodically, as the wheel wears, and the outer diameter changes. Of course, this means that you also need to check this adjustment if you swap between different wheels.

Some grinders have different adjustments for centering the wheel. Some do not have any. Since I use different grinders, I do a manual check* with each loop and and compensate as needed. The 520-120 grinder lets you do this a bit more precisely.

* I grind one side of the chain first (e.g. all the Left cutters); then grind one cutter on the other side (in this case a Right cutter). Hold a Left cutter back-to-back with the first Right cutter and visually compare. Make any adjustments as needed, then grind the rest of the Right cutters.

View attachment 900394

Philbert

Hi, Phil!

Nice post! I have noticed a small difference in length between my L and R cutters on my Oregon 620-240 grinder. Although I have set up the "sliding base" using the "steel ruler technique", this difference is still visible. It amounts to about a 1/4 turn on the chain advance wheel for the L cutters. Would you please explain your technique for adjusting to get both sides equal?

Thanks,

Mike

 

[Philbert]

Some grinders have the sliding vise base. Some have an adjustment screw on the vise that pushes the clamping plates forward or backwards. Some grinders have no adjustment for centering. But best to start with what is provided, and the user’s manual, if you can read it.

After that, as noted, grind one side first, then one cutter on the other side, and visually compare back-to-back.

If cutter length is different, adjust the tooth holding dog forward or back.

If cutter profile is different, raise or lower the wheel depth.

If top plate angles appear different, your vise rotation scales may need to be calibrated (e.g. ‘32* L and 28* R’, or whatever).

Whatever it takes to get the cutters even and symmetrical. Better grinders make this easier, but the final result is always up to the operator.

Philbert

 

[Mike Kunte]

Thanks, Phil!

As has been noted many times on AS, the Oregon grinder instructions are pretty useless. The 620 grinder has the hydraulic vise, so it may be a bit tricky to get it "self-centering". I notice that it grinds the RH cutters a touch strong. This means that when I grind the LH cutters, I need to advance the chain stop about 1/4 turn to get the lengths equal. It also means that when I start with the LH cutters, I have to remember to back off the chain stop 1/4 when switching to the RH ones. It would be handy if I could get them equal without having to adjust. Anyone with experience on the 620? Please chime in!
Thanks,

Mike

 

[Woodslasher]

Hi, Phil!

Nice post! I have noticed a small difference in length between my L and R cutters on my Oregon 620-240 grinder. Although I have set up the "sliding base" using the "steel ruler technique", this difference is still visible. It amounts to about a 1/4 turn on the chain advance wheel for the L cutters. Would you please explain your technique for adjusting to get both sides equal?

Thanks,

Mike

I was grinding a chain on my 520 grinder last night and I noticed the same thing. I used a set of calipers to measure the teeth on the short side, and then I gradually advanced the stop and ground the cutter on the other side until it was the same length. I ground a second tooth and double-checked that it was the same length before I ground down all the rest of the cutters.

 

[Mike Kunte]

I was grinding a chain on my 520 grinder last night and I noticed the same thing. I used a set of calipers to measure the teeth on the short side, and then I gradually advanced the stop and ground the cutter on the other side until it was the same length. I ground a second tooth and double-checked that it was the same length before I ground down all the rest of the cutters.

I was grinding a chain on my 520 grinder last night and I noticed the same thing. I used a set of calipers to measure the teeth on the short side, and then I gradually advanced the stop and ground the cutter on the other side until it was the same length. I ground a second tooth and double-checked that it was the same length before I ground down all the rest of the cutters.

Yes, this is common. However, Oregon claims that the vise is "self-centering". I wonder if it is thus adjustable. With the hydraulic vise it may not be?

 

[Philbert]

Just a thought: take a new, or ‘perfect’, chain and mount it in the grinder with the power ‘Off’. See what settings are needed to match cutters on both sides. Vice rotation? Vise base slide? Grinder head travel? Tooth positioning dog?

This may provide some insight, or guidance on how to compensate.

And let us know what you find!

Philbert

 

[Mike Kunte]

Thanks, Phil! I think you're spot on! I could not work it out, but now I'm certain that moving the vise slightly back will cure the problem. Thanks for your input! I'll be sure to provide feedback!

Regards,

Mike

 

[Philbert]

Thanks, Phil! I think you're spot on! I could not work it out, but now I'm certain that moving the vise slightly back will cure the problem. Thanks for your input! I'll be sure to provide feedback!

I learn from this stuff too!

Philbert

 

[JaIt]

Hmm, what about that scale on the bottom, what's the unit and what does the A mean ?

 

[Philbert]

Hmm, what about that scale on the bottom, what's the unit and what does the A mean ?

Welcome to A. S.!
I think that it’s best to consider those as reference numbers, so that you can repeat the settings, or adjust (‘a little more’, ‘a little less’). I don’t know what the ‘A’ means.

Philbert

 

[JaIt]

"Welcome to A. S.!"
I'm the original poster but thanks
It would be cool if those numbers were related to the current diameter of the wheel, that way one would just have to check the current wheel diameter and dial it... Even better, the wheels could have markings on them.
Anyway, thanks all for the answers.
Cheers

 

[Philbert]

"Welcome to A. S.!"
I'm the original poster but thanks

Ooops! Sometimes hard to tell when I check A.S. on my smartphone.

Welcome Back! (Seriously. Oftentimes we scare the 'new guys' away!)

Philbert

 

[JaIt]

Actually let me correct my post, correct me if I'm wrong but I think those numbers MUST match the diameter of the wheel which has a fixed diameter. So it's only a matter of someone checking the numbers on the scale with the correct adjustment against wheel diameter and make a table

 

[Philbert]

I once asked an Oregon representative about those numbers, and got a vague, non-commital, answer. So, I’m sticking with my description, unless you come up with something more convincing.

Philbert

 

[JD Guy]

Curious if anyone found out any additional information on the "A" tic mark and it's relevance? I am a new owner of a 520-120 and reading all of the posts that I can find to enlighten me and possibly shorten the learning curve.
Thanks!

 

[pdqdl]

It might sound more involved that is really is: just becomes automatic. Like a lot of other skill sets; no different than 'measure twice, cut once', etc. Or inserting a wedge into a kerf 'just in case.'
You should not have to adjust for wheel wear until the amount of wear is significant, or unless your wheels are of very different sizes. Remember that most grinders do not even offer this feature and people still use them. It offers you a higher level of accuracy and consistency, if you want it.


I did not like the CBN wheels I tried as much as properly dressed, good quality, AO/vitrified wheels. I might be an outlier on this, and maybe other wheels work better? I did not think that the CBN ground much faster. It's true that they do not change size, and they generate less grinding dust. But, on the other hand, I can change the profile of my vitrified wheels if I want to for custom grinds / profiles, and I grind outside.

Philbert

The CBN wheel's greatest advantage is how much less heat they produce while grinding. A good wheel will "cut" the steel with almost no sparks and you don't have much tendency to heat the cutters on your chains. You can take a heavily rocked hchain and cut clean to the final sharpening point without doing any bouncing with the grinder. In fact, the practice of "bouncing" the regular wheels to keep the cutters from overheating is somewhat destructive to the CBN wheels. They don't last as long.

What I have noticed over the years is that the CBN wheels start generating a lot more heat when sharpening a chain that when they were new. Due to the expense of the wheels, I always just slowed down the sharpening pressure so as to avoid overheating the chain and I also used brake cleaner to knock the accumulated oil and metal on the wheels to reduce the amount of heat they make. Reversing the wheels occasionally helps, too.