HF Chain Grinder Thread

[Philbert]

Retired my ‘Nick the Grinder’ after nine years of service. He was a freebie to begin with and developed random endplay in the motor bearings.

Sorry for your loss. I know that Nick was a loyal companion and friend to you.

Good call on swapping out the vice, I mean, letting Nick's memory live on in another grinder.

Philbert

 

[mountainlake]

IMO when you bring the grinding wheel low enough so the tooth is ground by the side of the wheel you get the same angle on the top part of the tooth as square grinding. I've been grinding like that ever since I go my 511a grinder 50 years ago and my chains cut great. A grinder and a file are not the same and no reason to try and imitate a file when grinding. I use a 1/8 cbn for all chains and they all cut great. Steve

 

[Philbert]

A grinder and a file are not the same . . .

Of course they are not, but that is irrelevant.

It is not a question of which tool you use, it is the matter of what you want your finished tooth / cutter to look like. I have posted the image below many times. If you like the cutting edges that you get by grinding with the side of the wheel, then there are files that match that profile. But if you prefer the performance of a round filed cutter, use the profiled edge of a correctly sized wheel to attain that.

IMO when you bring the grinding wheel low enough so the tooth is ground by the side of the wheel you get the same angle on the top part of the tooth as square grinding.

Square grinding involves many different angles, beyond a flat top plate bevel. Square ground chains are typically done at a much shallower top plate angle than the standard 30° used for round filing, and often at steeper top plate bevels (please reference the Masden's links, above, or one of the many square grinding / filing threads here on A.S.). It also only works on full chisel chains.

But more importantly, when you bury the standard grinding wheel that deep into the gullet, you change the side plate bevel shape and angle significantly, and that is the part that does the heavy work when crosscutting.

My standard line about sharpening is, 'Everybody has to find something that works for them.' So, if that is working for you, and you are happy with it, then stick with it.

Philbert

 

[mountainlake]

Of course they are not, but that is irrelevant.

It is not a question of which tool you use, it is the matter of what you want your finished tooth / cutter to look like. I have posted the image below many times. If you like the cutting edges that you get by grinding with the side of the wheel, then there are files that match that profile. But if you prefer the performance of a round filed cutter, use the profiled edge of a correctly sized wheel to attain that.

View attachment 854857


Square grinding involves many different angles, beyond a flat top plate bevel. Square ground chains are typically done at a much shallower top plate angle than the standard 30° used for round filing, and often at steeper top plate bevels (please reference the Masden's links, above, or one of the many square grinding / filing threads here on A.S.). It also only works on full chisel chains.

But more importantly, when you bury the standard grinding wheel that deep into the gullet, you change the side plate bevel shape and angle significantly, and that is the part that does the heavy work when crosscutting.

My standard line about sharpening is, 'Everybody has to find something that works for them.' So, if that is working for you, and you are happy with it, then stick with it.e

Philbert

The grinding wheel goes no where near as low as your exaggerated pic above and a file would still work fine after I grind, it might not hit the whole gullet but it hit the top of the tooth where it needs too. The BIGGEST mistake people make with grinders is not getting the wheel low enough resulting in no hook angle on the side plate, I've seen chains come in here ground like that and don't cut. Steve

 

[RedSleds]

New here, first post.
Plowed through this entire thread, and was surprised at the lack of mods to this HF unit.

Most interested in finding a mod for wiring motor for switchable forward/reverse direction of grinding wheel. Also, if anyone has replaced the hinge spring with one that requires less force at the bottom of stroke, so you don't need to ham-fist it and induce side to side flex. Re-bushing the hinge with tighter tolerance hardware would be a plus too.

I am considering filling the honeycomb of the base with epoxy resin. (to perhaps mitigate any flex from that area?)

My plan for this unit is mostly to use for achieving equal tooth length after replacing severely damaged links from foreign object strikes, and also after several in-the-field sharpenings with a Pferd CS-X(Stihl) 2-in-1 file guide.
After running the chain through the HF, I would then "fine tune" it with the Pherd.

Any thoughts, or pointing in the right direction, would be appreciated.

 

[Philbert]

. . . Most interested in finding a mod for wiring motor for switchable forward/reverse direction of grinding wheel. Also, if anyone has replaced the hinge spring with one that requires less force at the bottom of stroke, so you don't need to ham-fist it and induce side to side flex. Re-bushing the hinge with tighter tolerance hardware would be a plus too. . . I am considering filling the honeycomb of the base with epoxy resin. (to perhaps mitigate any flex from that area?).

Welcome to A.S., and to the rabbit hole of cheap grinders!

At $30, or so, it is a low financial risk to try and mod these grinders, so please let us know what you try and what works.

As shown in the photos, I have each of my HF-type grinders mounted to a wood base, for portability, and never really noticed an issue with flex from the base. Some of the better mini-grinders, such as the Oregon 310-120, have cast metal bases, which essentially have zero flex; the additional cost of that grinder might be offset by what you spend on epoxy!

Simple bushings can be good for reducing slop. My approach has been more from a technique approach: I use the grinder to help guide me, but do not force it. Sometimes, I use a little side pressure (or 'body English') to control the amount of material removed on a specific tooth. In other words, I am visually and tactilely controlling the grinding progress, and not relying solely on the machine. If you come up with some simple bushings, I am sure that folks would be interested.

As for re-wiring the motor, I have to stand back. First, due to the safety issues, and second, due to my minimal knowledge of motors. There are some diagrams in the larger grinder threads, but I do not know if they apply to this type of motor. If you are planning on 'finishing' the cutters with the Pferd 2-in-1, why even bother with reversing the motor? Any burr produced will vanish with the first or second file stroke. Your key challenge will be to match the profile of the Pferd file with the grinder, as closely as you can: 'Grind as you file and file as you grind!', so that the file is just finishing the cutter with a minimum amount of re-shaping.

Philbert

 

[Philbert]

Better Quality Forester Grinding Wheels for HF Type Grinders

I've mentioned the importance of the wheels when grinding chains, and how good wheels can really be an improvement over some of the fine grit, red/brown wheels supplied with many of these low cost grinders. So I was happy to find these Forester brand wheels for the mini-grinders at that store where 'You Save BIG Money', especially with the price: $10 for a 'bonus pack', including an 1/8" and a 3/16" grinding wheel. This is lower than what these wheels list for individually on eBay.



As noted, the fit can be tricky: some grinding wheels have an ID of 7/8", and some 22mm. Even though they are close (and sometimes mislabeled) they have to match the arbor on your grinder. Too small and they will not fit. Too large and they wobble (or worse!).

I tried them on a few of the 'HF type' grinders that I have. They fit the older style, 'Chicago Electric' (Harbor Freight brand, without the bicycle brake lever chain vise), and the similar looking 'Nick the Grinder'. But they did not fit an identical looking 'Infinity' grinder (seriously, you could not tell these grinders apart, except for the colors). Forester says they will fit their grinder, and the Oregon models, but I do not have these to try. So keep your receipt and test fit them on yours.

As with the better quality Oregon wheel (Post #188), this made grinding fun! These smaller, lower powered, fixed angle grinders have their limits: they are good for restoring edges on cutters, but limited for fixed damaged teeth, custom angles, or doing depth gauges. But they are small, quiet, and inexpensive.

I went looking for more loops to sharpen. I did several 20" loops of STIHL .325 pitch chain and was pretty happy with the results.



Some of these grinders were only sold with the 1/8" wheels, which is too narrow for larger pitch chain. The 'Nick the Grinder' grinder took the 3/16" wheel with no problem. My 'Chicago Electric' grinder had enough threads on the arbor to hold the wheel, but will need a little trimming on the cover guard for additional clearance.



Nice to have decent quality, inexpensive grinding wheels to use with inexpensive grinders. So far, I have only seen this packaging at Menard's. Hopefully, it will become more available.

Philbert

 

[Philbert]

Nice to have decent quality, inexpensive grinding wheels to use with inexpensive grinders. So far, I have only seen this packaging at Menard's. Hopefully, it will become more available.

Of interest (to me at least) is that the grinding wheels supplied with the old style, Chicago Electric (Harbor Freight) grinders (before the hand brake, cable, vice thing) were coarser grit, and made by MoleMab in Italy! Worked much better, IMO, than the fine grit ones now supplied.

Phiblert

 

[Philbert]

Just call me 'Angle' of the morning . . . .

I have been evaluating a few more of these less expensive, mini-grinders (will post some separate threads on each), and noticed something interesting. Although, the grinder head tilt angle is fixed on most of these, they are not all fixed at the same angle (!). At first I thought it might be an illusion, or a perspective thing. And no one cares about a variation of a degree or two on this type of tool. But a couple of them looked significantly different. So I took them down into Philbert's Secret Underground Research Laboratory ('PSURL') and applied SCIENCE (or engineering, or math, or something) on them.

Hard to measure with a standard protractor, so I clamped the heads down, inserted a small piece of card stock in each vise, traced the line, and measured it off the paper (highlighted in these photos for emphasis - those lines did not actually appear).


Here's what I got -presented a couple of ways, in case one makes more sense:





Small differences may be due to my measuring error. But the 10° difference between the Grizzly and Forester (identical to Oregon 310-120?) is H-U-G-E!

60° has long been the 'standard' / 'default' angle for cutting a variety of different types of wood, and what STIHL usually recommends. Oregon has been recommending 55° for most of their chains for several years now. It is a separate discussion to decide which is 'best', which cuts faster, which lasts longer, etc. Of course, on 'standard' grinders, this angle is adjustable. But if these details are important to you, and you are thinking about one of these fixed head angle grinders, this might be interesting information.

Philbert

 

[mountainlake]

Heres a nice vid on sharpening, at the 1:33 time notice hoe he gets the wheel low enough so theres a nice hook angle on the side of the cutter the way it should be. I was sawing logs for a customer who had his chain sharpened at a shop, it had decent hook on one side and none on the other side from not getting the wheel low enough and cut like $%$#. Steve

 

[Philbert]

. . . a customer who had his chain sharpened at a shop, it had decent hook on one side and none on the other side from not getting the wheel low enough . .

Sometimes the difference between R and L cutters is that the grinding wheel is not centered over the vise.

Since the grinder head pivots onto the cutters, one side could be ground by part of the wheel to one side or the other of the center line. And this changes as the diameter of the wheel changes with wear. Usually a small difference, but can be an issue in some cases.

Hard to get a good illustration right now, but this is from the Oregon 520--120 manual: one of the few grinders that lets you adjust for this as the wheel wears (some grinders allow small adjustments in the vise). The mini-grinders in this thread do not offer this type of adjustment.


The vise on the Oregon 520 adjusts forward and backwards to compensate for this. I just 'run' the L side cutters:then run a sample R cutter; stop; compare; adjust if necessary; then run the rest of the R side.

Philbert

 

[mountainlake]

Yes the shop that sharpened that chain needed to adjust the height of the wheel when switching sides but didn't. Steve

 

[Philbert]

I've mentioned the importance of the wheels when grinding chains, and how good wheels can really be an improvement over some of the fine grit, red/brown wheels supplied with many of these low cost grinders.
. . . As with the better quality Oregon wheel (Post #188), this made grinding fun!

Another odd thing about the 100 grit, red/brown, fine grit wheels that come with most of these mini-grinder: they don't pass the 'ring test'!!!


The Owner's / User's Manuals that come with these tools all stress the importance of inspecting the wheels before use, but none of the fine grit, red/brown wheels I have give more than a 'thud' sound, even though they run fine. Must be too dense?

Philbert

 

[Philbert]

Northern Tool / Northern Hydraulic Grinder Reference

In the second post in this thread I included a link to one of the NT / NH grinder threads. It was one of the first, popular clone grinders, which copied the Oregon / Tecomec style at a fraction of the price (and quality). Since then, I have occasionally had trouble finding the 'BIG' thread on those grinders (even though I posted in it), so I am adding it here for reference. Interesting to note that Northern Tool has cycled through several different versions of these 'clone' grinders since we first started seeing them 14 years ago! Some of the same issues, and tips may still apply to the current offerings.

https://www.arboristsite.com/community/threads/fyi-northern-chainsaw-sharpener.39995/
Also:
https://www.arboristsite.com/community/attachments/tuning_chinese_chainsaw_sharpener-pdf.566900/

Philbert

 

[Pupa57]

I have a two variants of this type of machine. First the full plastic model and second the lower aluminum top plastic version. Since I cut in three different locations in Austria, each a few hours drive apart, I................

7

https://www.arboristsite.com/community/threads/hf-chain-grinder-thread.268303/post-5092608
Although the above was posted long time ago, I yet found it quite adequate even today. Very good and direct post giving me the confidence boost I needed. I just acquired a bargain "HF" equivalent cheapo sharpener from someone who advertised on an auction type site. He apparently used it once and then rather preferred sharpening with a Dremel tool and grinding stone. My luck, as I needed something to sharpen a chain urgently.
I bought a generic China Chainsaw version model CS-4500 during Black Friday special, felled two smal trees with 200mm trunks, green softwood, and to my surprise the supplied Chinese chain, with name Alston on links, on closer inspection was badly blunted. It could not cut properly anymore. I was shocked. I could not find a replacement 18"/72 DL/325/0.058 chain locally. I then attempted sharpening the chain myself using the supplied abortion of a “file” but the bad quality cheap China file was the wrong size, it was too small and was blunt in itself by the third cutter sharpening attempt. Please note that this was my first attempt, in desperation, to sharpen a chain. I did a lot of research and watched many sharpening videos since the issue presented itself.
In the past I just had a replacement chain installed on my cheapo Chinese electrical chainsaw when the original chain was blunt, thus in total I used two chains over the span of many years before the chainsaw broke a gear.
I have quite a few trees to remove so bought Ryobi 4mm files to further attempt the sharpening, the files were better quality, much longer and the right size, etc. I tried sharpening some cutters but was not confident at all. So when I saw the advert of the available electric sharpener on the cheap, it was like I had destiny with this device. I immediately grabbed the offer and bought the device and was ever so excited at first, then I read the reviews and was disheartened some. I was very concerned indeed. I decided to first play with this sharpener device to verify all the flaws and problems I saw and read about on so many sites and only then will I attempt to do the required or recommended mods I can manage as per the videos. In the meantime it started to rain for a few days giving me more time to play eith the unit and do further research to procure a locally available chain for this saw.
I was happy when, with another stroke of luck, I found a reference about a Chainsaw supplier with a quality Oregon chain, with the correct specifications as required, repackaged under their own Chainsaw brand. I ordered online and once received gave it a test run when weather allowed. What a difference a quality brand chain makes.

Back to the chainsaw sharpener.
I have done some mods based on my newfound knowledge and also based on some of my own observations. I am considering more ideas on improving the subpar brake clamp design.

Some mods I’ve done so far:

Did not find much of a problem with the loose and unstable pitch distance control flapper but added some large washers anyway (scrounged from my scrap bin) to improve stability some more.



I found the bar/clamp unit not very straight, with a varying gauge gap right through, and thus stripped the unit to measure the sprocket thickness determining the gauge gap. I measured them as 1.54mm. I found some nylon spacers from my tinkering box with close to the exact measurements and installed one spacer between the rail plates at every screw possible holding the unit together to maintain the gauge gap at +-1.5mm throughout. Thus the chain movement using the knobs forward and backward are smoother and the chain fits snuggly and stable in the "bar".

As for the clamping plate pulling in at an angle at the bottom when using the brake, which tend to randomly lift and offsetting the cutter position during the clamping action, I placed three of the nylon +-1.54mm spacers on the bottom screw below the clamping plate. I also added additional and stronger springs on the two top screws above and towards the sides of the clamping plate. This increased the steadiness and repeatability of the clamping greatly.

Unfortunately I found the clamping, in the sharpening position, are mostly just clamping on one drive link leaving the cutter in a position that allows it to swivel upwards when touched by the grinding stone. Especially on the reversed angle when sharpening the 2nd set of cutters. To explain better; when I move the chain out of position to clamp the full width of one cutter, that means across two drive links then I cannot easily move the cutter upwards to swing. When moving the chain to the grinding position and the chain reversed tightly against the pitch stopper plate, then only one drive link are clamped and the cutter can then easily be swivelled upwards, again it’s more prominent during the 2nd set reversed angle sharpening stage. My solution is to modify the clamp block to be wider to clamp over at least 2 maybe 3 drive links at the same time.

After these changes were made, I felt much more confident and yesterday sharpened the cheap China chain "successfully?” At least back to a state to operate again.

I swopped the chains and made the China chain attack some wood. Mostly small trees and branches. I was happy with the improvement so I can only give this sharpener a thumbs up. I am feeling confident that it can only go better from here on.

Other changes I am considering;

Dump the brake and use a electrical solenoid to clamp the chain, using a wider clamp over three drive links as discussed above. The clamping action can be automated to clamp when the grinding stone head leaves the home position. A foot switch can also be considered?

I am still considering the need to reverse the motor during the 2nd reverse angle sharpening exercise?
Improve the stability of the grinding head unit using bronze bushes on the 10mm swing pin?

Improve the stability and thus reduce the flexing of the head uni,t which are causing movement of the grind position, by using an epoxy (or Plaster of Paris?) to fill the open spaces that can be seen down under when the sharpener are viewed from the bottom?

That’s it for now.

Thanks for a nice thread instilling the confidence to use this affordable sharpening unit effectively.
More photos and videos to follow as work progress, sooner than later.
Any advice or comments will be welcomed.

 

[Philbert]

Welcome to A.S.!

Thanks for the positive feedback.

The bottom line is how the cutters look when you are finished. How you get there is up to you!

Philbert

 

[Pupa57]

Welcome to A.S.!

Thanks for the positive feedback.

The bottom line is how the cutters look when you are finished. How you get there is up to you!

Philbert

Thanks for the welcome.
Found the edit.

Its difficult to know when the cutters are acceptable due to lack of experience and information. Will take some snap's and present here for advice if possible.

 

[Philbert]

Is it possible to edit my thread to add info or do corrections?

On this site, you can edit your own posts up to 24 hours. Click 'EDIT' at the bottom of your post.

Please also share any photos of your modifications, as well as failures, successes, etc. for others to learn from.

Philbert

 

[Wood Doctor]

I bought Oregon OR4125-316A Grinding Wheel 3/16 Inch. I just used saw yesterday, sharpened with original HF wheel....and did rakers. Man it cuts very Well. I don't understand why the HF grinder has so much hate.

It gives a flat cut surface, I don't know if that's considered a square cut, but it cuts great. Yes, the original wheel doesn't give the smoothest finish. I will try the Oregon wheel.

I also don't see why a bigger motor is needed. Its just kissing the teeth, unless your chain is really mangled.....but even so, mine doesn't have a issue. I don't try to lug it down though....

You were able to mount a 3/16" thick wheel on this grinder? Mine would not accept it. Only 1/8" thick wheels would fit, and anything thicker would rub the outside guard and make the thing sound like a contraption. I recently got around this barrier by using #8 or #6 flat washer shims, underneath the little mounting crews between the guard and the housing to give it more room. That worked. I also did a few more things as I show in the last two pics:

The swivel stop that sets and holds the cutter fell apart on mine. I replaced that as shown with a short length of angle iron and a nut and bushing, all bolted in place and held with a lock nut. So far so good. It's back into service.

 

[Philbert]

Summary (sort of) . . .

6 years and 16 pages (!), based on a taunting dare from a fellow member. At one point, I had 11 of these puppies in my basement, trying out different variations. I still refer people to this thread when they ask about HF grinders. So, here is sort of an interim summary. 'Interim', because I may get drawn down that rabbit hole again.

- These grinders are attractive due to their low price. But they also take up little space in use; are compact and portable to transport and store; and pretty quiet, compared to 'conventional' grinders. In a sense, they are 'cute'!

- They have limited power and limited adjustability.

- If you are satisfied with the 'standard', fixed angles, are mostly 'touching up' worn edges, and understand what a finished cutter looks like, you can absolutely improve chains with these tools. If you are planning on custom angles, fixing badly damaged chains, or setting up a sharpening service, keep looking.

- Many of these are of 'modest' quality (some are junk). Repair or replacement parts may not be available. Some of them are of decent quality, but those tend to cost more. Although, price and quality are not always linked, 'you get what you pay for', should be in the back of your mind.

- *The grinding wheels are critical*. Better wheels grind better. Some of the 'better' wheels cost more than some of the cheap grinders (!). Many of these grinders only accept 1/8" thick wheels, which means that you will need to reposition larger pitch chains (multiple passes) to get a 'proper' grind.

As with any grinder (or sharpening method), it takes some knowledge, some experience, and some skill to become competent and efficient. These could even be considered a low cost, fun thing to try, for less than the price of a couple of pizzas, movie tickets, etc., if you understand the limitations. I absolutely prefer my 5-3/4" Oregon / Tecomec grinders over these for regular use, but understand that the $200 - $300 price of these is more than some guys can justify. For some guys, filing chains is a better option.

Most of my 'HF-style' grinders have now been sold off on CraigsList or garage sales: I just was not going to use them. I did keep a pair of the Forester 04844 / Oregon 310-120 style grinders, with better quality wheels installed, for fun, light-duty use.
https://www.arboristsite.com/community/threads/forester-04844-chain-grinder.347765/
All that rationale stuff aside, my head still turns instinctively when I see one in a store, on-line, CraigsList, garage sale, etc. I have to remind myself that I am not running a museum, adoption shelter for grinders, etc.

Philbert