Raker height with grinder

[AaronB]

I am going to do my rakers on my grinder using the progressive method that BobL showed me, or basically getting 6° with an angle gauge.

My questions is this, the manual states to have the grinder head at 0° but it doesn't say anything about the shape of the wheel. Does the wheel need to be dressed a certain way or can you just use a flat wheel to lower the rakers.

Thanks

 

[flushcut]

I don't know about your grinder but mine said lay the dressing block on the chain vice to true the wheel. I can't remember if it is at an angle or not I have always filed my rackers by hand.

 

[mtngun]

My questions is this, the manual states to have the grinder head at 0° but it doesn't say anything about the shape of the wheel. Does the wheel need to be dressed a certain way or can you just use a flat wheel to lower the rakers.

I only recently started to use a grinder on rakers, so I haven't perfected my technique yet.

Zero degrees doesn't sound right to me. I tried several angles, can't remember which one worked best, but I think it was 70 or 80 degrees.

I used a flat wheel, but next time I will probably try to dress the wheel to have a concave face.

 

[Pulp Friction]

I am going to do my rakers on my grinder using the progressive method that BobL showed me, or basically getting 6° with an angle gauge.

My questions is this, the manual states to have the grinder head at 0° but it doesn't say anything about the shape of the wheel. Does the wheel need to be dressed a certain way or can you just use a flat wheel to lower the rakers.

Thanks

Not sure what grinder you're referring to, but my manual for the 511AX states that you set the grinder head angle at 60 degrees. This is the same angle as my chains get. Then they say to set the "Vise Angle" to zero degrees. This is the adjustment that I normally have on 30 or 35 degrees for sharpening cutters. Then they say to lay the dressing brick onto the chain clamp and dress the 1/4" wheel to a flat. With the 60-dgree tilt, this will put a wider flat on the disc than the 1/4" wide.

Now I have a question. Today I went out and got a Harbor Freight electric grinder (on sale for half price at $24). First let me say, what a P.O.S.! The first one had to be returned immediately and exchanged because it was aparently used to grind chains already. The wheel was already installed and metal dust was all over it. The mounting holes clearly had bolts installed prior as the compression into the plastic was evident. The manual was gone too. This was the box that the wife pointed out as looking "sealed up" better than the one I had initially picked up, so I took the one she liked! So after exchanging it for a virgin unit, I mounted it on the opposite side of the pedestal stand as the Oregon grinder is mounted and wanted to leave it set up just for rakers. However the diameter of the wheel is only 4-1/4" and due to the molded plastic housing, will not accept anything larger like the oregon model. Since it only came with a pink wheel 1/8" wide, I want to put a 1/4" wide wheel on it. It uses the same 7/8" arbor hole though. Are 4-1/4" diameter wheels available in 1/4" wide, and has anyone ever put one on a Harbor Freight grinder? I'm hoping the tiny motor can handle the added inertia of a heavier wheel, and that the housing is wide enough to contiain a wider wheel.

 

[AaronB]

I found another manual online and it made pretty good sense, but I haven't checked the angle is said to use vs what the raker looks like new, but it will be better than using those raker guides with a flat file.

Here is what it said:
1.) Turn the vise to 0
2.) Turn the arm (head) to 10° or 15° ((***mtngun*** this 10-15 is away from 90 so that would be range from 80-75 which is what you stated, so that sounds good to me))
3.) Position the dressing brick on the jaws and against the chain blocking unit (chain removed)
4.) Profile the grinding wheel by lowering the head against the brick.
5.) Remove brick, install chain and grind rakers.

I think I will try this method and see how it goes, I was just using those little depth gauge things with a flat file so this 10°-15° seems like it will work pretty good, plus it will make doing them much faster.

 

[Pulp Friction]

Aaron, turns out Harbor Freight does sell aluminum oxide grinding wheels, 1/4" wide and 4-1/2" diameter. In fact they have a 10-pack of an assortment of other cut-off wheels and flap-discs too for the 10.99 so I think I'll head there right now and use a 20% off cupon. Looks like 4 or so wheels of what I need are included.

So before I dress the wheel on the steep 60 degree angle, am I getting you right that it should only be 10 or 15 degrees off of perfectly horizontal? This more gradual slope makes more sense to me.

 

[AaronB]

Aaron, turns out Harbor Freight does sell aluminum oxide grinding wheels, 1/4" wide and 4-1/2" diameter. In fact they have a 10-pack of an assortment of other cut-off wheels and flap-discs too for the 10.99 so I think I'll head there right now and use a 20% off cupon. Looks like 4 or so wheels of what I need are included.

So before I dress the wheel on the steep 60 degree angle, am I getting you right that it should only be 10 or 15 degrees off of perfectly horizontal? This more gradual slope makes more sense to me.

It should be 10-15 from vertical, that would make the setting on my grinder 80-75, since 90 is vertical on mine. So if your wheel is straight up and down (vertical) it would be off that. Going to try it this week sometime.

 

[mtngun]

I'm not following why you would want to dress the 1/4" wheel with the head tilted ? That will result in the top of the raker being horizontal, rather than angled or rounded.

Here's what the manual recommends, but I'm not buying it.

If you must use a flat wheel, I'd suggest leaving it flat, and tilting the head to 75 - 80 degrees to produce an angled raker.

I'm planning to try to dress the wheel to be concave, so that it will produce a rounded raker.

 

[Pulp Friction]

I'm not following why you would want to dress the 1/4" wheel with the head tilted ? That will result in the top of the raker being horizontal, rather than angled or rounded.


If you must use a flat wheel, I'd suggest leaving it flat, and tilting the head to 75 - 80 degrees to produce an angled raker.

I'm planning to try to dress the wheel to be concave, so that it will produce a rounded raker.

I think maybe the reason why they want the wheel dressed flat but on an angle is because it will then match the same angle that the raker sits in the vise. It would seem to make more sense to just leave the wheel flat right out of ther box but just tilt it to match the angle of the raker and then grind away.

Now here's the outcome of my trip to Harbor Freight for grinding wheels. They only seemed to have aluminum oxide metal-grinding wheels with the concave step in the center where the arbor goes, even though it still had a hole for the 7/8" arbor. The wheels they sell are 4-1/2" diameter where the sharpener they sell uses a 4-1/4" wheel, flat both sides, and 60 grit. They sold replacement wheels for their grinder, but they are 1/8" thick. Are 4-1/4" diameter flat wheels with a 7/8" arbor hole, 1/4" thick, a common wheel that I can find elsewhere? They had lots of 3" dia. cut-off wheels and maybe grinding wheels too but I think with a 5/8" hole in the center.

 

[Racerboy832]

I must of been doing it all wrong. I set the grinder to 90 and O on the deck. Find .030-.035 height and the set the stop. I then slide the raker across the wheel in one direction. I then spin the chain and do it in the other direction. The reason I spin the chain is cause I can only do one side of the rakers cause then are tilted back. If I do all the ones that are tiltled towards me it's really grabby on the wheel and i'm afraid of breaking it.

 

[mtngun]

Are 4-1/4" diameter flat wheels with a 7/8" arbor hole, 1/4" thick, a common wheel that I can find elsewhere?

Doesn't look like it.

Bailey's offers a 3/16" wheel, it might do the job. 3/16 x 4 1/8 wheel

 

[Pulp Friction]

Bailey's has it. I just found it and ordered it this morning with a bunch of other stuff. This wheel should fit the Harbor Freight grinder as long as it's not too thick to accept the arbor. It's only twice as thick as the supplied 1/8". If worse came to worse, I won't be able to bolt the wheel-gaurd back on.

http://www.baileysonline.com/itemdetail.asp?item=ORF+412514A&catID=

 

[AaronB]

I'm not following why you would want to dress the 1/4" wheel with the head tilted ? That will result in the top of the raker being horizontal, rather than angled or rounded.

Here's what the manual recommends, but I'm not buying it.

If you must use a flat wheel, I'd suggest leaving it flat, and tilting the head to 75 - 80 degrees to produce an angled raker.

I'm planning to try to dress the wheel to be concave, so that it will produce a rounded raker.

I was kind of thinking the same thing about the way they show to dress the wheel, doesn't seem right. I agree about leaving the wheel flat at the least and just tilting the head but making it concave would probably be best but I probably won't try it this time. Since I was just using a flat file anyway the raker isn't as rounded as it was when it was new but if I get that 6° or close I'll be happy.

 

[AaronB]

Finally got around to it this morning and I don't think I will ever do rakers by hand again. this was just to easy and got just as good as a result as doing it with a flat file.

Here is a shot of what it measure before I started.
View attachment 174938


here is what I got afterward, which is close enough to the 6° I was going for, some are more anyway, more on that in a minute.
View attachment 174939


Here is how I dressed the wheel, not much of a concave but a little bit, enough that helped it not just be flat like a file would be.
View attachment 174940

Went pretty well, only thing I saw was that the jaws in this sharpener are not self centering like some are, so I should of moved the jaws under the center of the stone for both sides and did one side at at time, but I didn't want to mess with that right now. It probably caused a little inconsistency in the angle were one side might be more than the other but it will work this time just to get me ready.

 

[mtngun]

I like your contoured wheel, that ought to work just fine.

What kind of grinder do you have ? I didn't recognize it in your pics.

 

[Jim Shockey]

Finally got around to it this morning and I don't think I will ever do rakers by hand again. this was just to easy and got just as good as a result as doing it with a flat file.

Here is a shot of what it measure before I started.
View attachment 174938


here is what I got afterward, which is close enough to the 6° I was going for, some are more anyway, more on that in a minute.
View attachment 174939


Here is how I dressed the wheel, not much of a concave but a little bit, enough that helped it not just be flat like a file would be.
View attachment 174940

Went pretty well, only thing I saw was that the jaws in this sharpener are not self centering like some are, so I should of moved the jaws under the center of the stone for both sides and did one side at at time, but I didn't want to mess with that right now. It probably caused a little inconsistency in the angle were one side might be more than the other but it will work this time just to get me ready.

Aaron,
It has been a long time since I've done any milling or sharpening on the grinder but, The way you are measuring the angle seems to be wrong to me.
I always kept the stone at the angle that I wanted the raker set at,8 or 10 degrease, and then come straight down on the raker to what ever hight that I wanted. I guess that it could be done the way you are doing it, I never done it that way. Could be a better way of doing it, just never seen it done that way.

 

[mtngun]

The way you are measuring the angle seems to be wrong to me.

Jim, see this thread for more than you ever wanted to know about what Aaron is trying to measure. http://www.arboristsite.com/chainsaw/114624.htm

 

[Jim Shockey]

Jim, see this thread for more than you ever wanted to know about what Aaron is trying to measure. http://www.arboristsite.com/chainsaw/114624.htm

I should have read a little more on the subject before I made a comment. That is all new to me and could be a very good way of doing it. I was comparing apples to oranges again. Sorry, Jim

 

[Wood Doctor]

Raker Contour--Fact of Fiction?

Well, one thing for sure, after reading this thread, I have a new appreciation for raker contour. However, I would like to see the proof in the pudding. How much additional cutting speed will I pick up if I contour the grinding wheel concave vs. leaving it flat?

If no additonal cutting performance is obtained, then it's a waste of time. Regardless, nothing ventured nothing gained, so this thread gets a top rating in my book.

 

[mtngun]

How much additional cutting speed will I pick up if I contour the grinding wheel concave vs. leaving it flat?

Do you mean flat horizontal, or flat angled like an FOP ?

Personally, I am fine with the FOP-style flat angle.

However, every time I post a close up pic of my chain, experts weigh in to remind me that I should contour the rakers. If I can contour the grinding wheel to produce a contoured raker, that'll shut up the critics so I can focus on more important things like experimenting with different grinding angles and raker angles.