honing disposable planer blades

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Oliver Springs, TN
I have a 13" delta planer with disposable blades. I've found that it the ridgid, steel city and craftsman all use the same size blades. When I need new ones I've been getting them from Sears. It's the cheapest place I've found them and they cost around 25 bucks.

They are reversible and both sides of the blades have become dull. I know they aren't supposed to be resharpened. I thought I would try honing them and see if it made a difference before I went and got a new set.

I started by cleaning the blades. I then used some spray adhesive to glue some 600 grit wet dry paper to a 3/4 inch piece of mdf. I used wd 40 to lube the paper. I put the blades in a vice and honed the bevel by hand. I then placed the blade on a flat surface and honed the back of the blade. I did this to both sides. Man, did it make a difference. I ran a board through to test the cut and it was like a new set of blades.

I just thought this might help someone else.
 
I've got the Rigid planer John and have thought about doing the same thing. Of course it won't help nicks in the blade but honing sure won't hurt. For the sharpening aficionado's out there- you're probably aware that there is a big difference in how well a blade is honed and the relationship between that and how long a blade will hold it's edge. ( also the edge geometry) Of course this is related to both the blade material and hardness as well as what you are cutting with it.

I would guess that the manufacturer's set the angle of the blade in the cutter-head to a generic all around angle. Something that will cut most woods adequately. I have wondered if tipping the blade one way or the other might not allow for a better finish cut on figured woods. The shimming on the blade would have to be done right to keep the shims from exiting the planer as shrapnel. but if the blade was set with a dial indicator I imagine you could get it pretty true.

Maybe I'll have to run an experiment or two.............
 
I wonder if this would work on the DW735 type blades with their indexing holes. If its just honing i can see it working but if its taking off too much like a regrind then I would worry. Anyone tried this with the Dewalt?
 
I have done as John said, and I also take my 12 1/2" Delta double sided blades to my Makita wet sharpener if I have light nicks with great results. I have sharpened them three times so far with no problem, However I am careful of how much I take off and would never try to go too far with them. A well worthwhile investment for me so far. Also do my joiner blades and plane irons to a point that they will easily shave hair on my arm.
Chuck
 
There used to be a really good sharpening service close to home that told me they could resharpen the Delta blades 3 times before they needed to be replaced. I never measured the blades before and after, but I'm fairly certain they used a very light touch. Beats the dickens out of replacing them each time they get dull.

OTOH, it's a great source of high speed steel for marking knives, etc.
 
...I thought I would try honing them and see if it made a difference before I went and got a new set.

John,

My local tool guy, whom I trust, had this to say (over on the Canadian Woodworking Forum) when asked about re-sharpening the disposable blades on a DeWalt dw735:

"Who told you they could be sharpened? They cannot. If you sharpen them, it throws off the relationship between the knives/head and infeed/outfeed rollers. Might work once, if you just honed a hair off, but that is about it. "
 
Thanks for the link Art.:thumb:

I was under no impression that I could resharpen my blades. They're only about an inch wide. I was curious to see if a light honing on the blades would make them last longer. I only made about 15 or 20 passes on the bevel and then the back. I could still see the factory mill marks on the blades. I don't think I removed very much metal at all.
 
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Art, I'm a tool and die guy and I would have to differ with your tool guy. I don't much use the stops on the planer and one can take off a fair amount of wood in one pass so I figure all you change is the maximum depth of cut in one pass. It would change the distance to the stop settings so that once the planer was down to the 3/4" stop it might be a little fat yet. That is a small problem vs the cost of new blades. If you sharpen the blades and they still cut then there is no problem.
 
Paul I think you misread my note. This is not about depth stops, it is about the relationship between the cutter head and the feed rollers that pull your board through.
 
Art, I did not mis-read what you wrote. The only relationship between the feed rollers and the cutter-head that really matter is the offset between the infeed roller and the outfeed roller. Ridgid recommends no more than an 1/8th" cut in one pass. So the question is how is this 1/8th" realized? If you sharpen the blades you simply reduce how much you can take off in one pass, and your depth of cut indicator may be off. The simple matter is, if the machine still cuts wood then it still is doing it's job.

I looked a little closer at my machine and it looks like the rollers are fixed and not on springs although I would have to see a blueprint or tear the machine down some to prove this. It makes sense that the infeed roller would be under spring pressure and the outfeed roller fixed so I guess this is the case. In this case you might cause the outfeed roller to have more pressure on the board because the blades are taking less wood off. The rubber on the rollers does deform under finger pressure so this should not cause much of a problem.

On the Ridgid planer the rollers are either geared or chained together. So I suppose the worst thing that could happen is that you might cause a higher load on the motor driving the rollers and therefore cause the motor overload to kick in.

I certainly am not trying to offend you or anyone else. I just know that there are misconceptions about and sometimes companies say things for their best interest rather than what is practical in reality.

My favorite misconception has to do with chainsaw chain sharpening. There is a popular myth going around in some circles that you should only sharpen a chain by filing from the back of the tooth toward the front because if you file into the tooth you will peel the chrome off???? The reality is that chrome doesn't care which direction it is filed in. It is simply chrome. The reason for this myth is because the manufacturers felt that by filing into the tooth there is a greater risk of slipping and getting cut. (I suspect the lawyers had some say in this)

IF you file into the tooth you get a sharper chain because you are not rolling a burr off of the cutting edge. I wear gloves. It is also a little harder this way.
 
John,

My local tool guy, whom I trust, had this to say (over on the Canadian Woodworking Forum) when asked about re-sharpening the disposable blades on a DeWalt dw735:

"Who told you they could be sharpened? They cannot. If you sharpen them, it throws off the relationship between the knives/head and infeed/outfeed rollers. Might work once, if you just honed a hair off, but that is about it. "


Im not really familiar with the small planers but on most larger planers theres a pressure bar that needs to be set within a thousandth of the bottom of the arc of the cutterhead that keeps pressure on the board. On larger planers this bar can be adjusted when you replace or sharpen the blades but on cheap portable planers there is no pressure bar and the feed rollers keep the pressure on the board before and after the cut, on most of these planers these rollers cannot be adjusted and by honing the blades you could cause the rollers to be under more pressure and if you reduce the cutter head diameter enough the board just wouldnt go through

Paul, most planers are set for a maximun cut and made so if you set it for a certain measurement you cant fit a board thicker than that measurement + the maximun cut into the machine

and for the angle of the knives in the cutterhead,I would NOT shim the knives but you could grind them at a different angle as long as the bevel didnt interfer with the rotation of the knives during a cut, but you really cant do this with a portable planer cause it cant be adjusted
 
I'm just going to make a comment and then duck. John D. found a nice way to extend the life of his blades, and it works well for him. He then shares that technique in the hopes of helping others. Then we have a discussion over whether or not his technique works.....So my comment: never argue with success. And to John D. - thanks.

[I bought a DeWalt 733 because I wanted resharpenable blades.]
 
I'm just going to make a comment and then duck. John D. found a nice way to extend the life of his blades, and it works well for him. He then shares that technique in the hopes of helping others. Then we have a discussion over whether or not his technique works.....So my comment: never argue with success. And to John D. - thanks.

[I bought a DeWalt 733 because I wanted resharpenable blades.]

well ken you make a good point, but lets say for the sake of safety,, that it worked for mr X and then others that might be more knowledgeable in the workings of different tooling methods see something that a regular joe didnt and didnt have happen this time.. we havnt got in anyones face like happens in some forums as of yet, just a few people doing some more research on a possible safety or best use of the tool in question.. if i were to try something and it worked for me lets say i was back cutting on a router table and it worked not problems so i wrote that this is really neat way to stop trouble and yet yu or another knew it was unsafe but for some experienced users in a very few circumstances... i would want to know i was walking on thin ice ken. and i think what was mentioned at the beginning is not a harmful thing but the angles and settings like the tool and die guys are mentioning can enter in and this is something that whom ever trys this needs to watch for.

thanks to all who have offered advice and research into this and thanks for not being like the other forums that would get down right nasty on something like this,, my way or the highway attitude...:D:thumb::thumb:
 
I think I would have the tendency to hone only the Flat side, which should make it better, and forget about the angled edge.

I would lightly hone as to not remove a whole lot of metal... just a "scoach" as Chas.Neil would say...

I would watch it very closely to see when the machine was not cutting at the proper depths per the gauges... and have a New set ready to go when that point came along.

Then, I'd save the old blades for making other Shop made tools... Many articles are showing up about Shop Made tools... using old planer & BS blades.

I don't think the intention was to "take the place of new blades" but to buy time in order to get new blades. (I have found that eBay is really good for these... but does take a little time)... Honing them a tad would make'em last for a little longer...

To me, I'd try it... If it didn't work satisfactorily to my standards, I would replace them & be done with it.
 
Well Eric, I suppose your comment is in regards for safety and that's fine. I do have a lot of experience with tooling both in use and design. I have designed cutters in fact and have found that many things are done because "that's the way everyone else does it" or "that is the way we have been doing it for years". This is where innovation or specialized knowledge can make gains sometimes. Case in point is the insert tool planer cutter heads that use more shear in the way they cut wood. Sometimes just by changing the relief angle or rake angle of a grind on a cutter can make a big improvement on how it performs cutting a specific material. My comment wasn't made off hand with no knowledge of the subject. Nor would I shim a cutter in a haphazard fashion. I do appreciate your concern and I wouldn't recommend that the average Joe try something like this.

My experience is more with machining metals. In some ways this seems more simple to me compared with the plethora of woods and their different physical properties. So my question goes to the idea that industry designs a cutter that will cut most commonly used woods satisfactorily. I collect and use woods from all over the world, especially figured woods. Their physical properties seem to be "all over the map" in regards to hardness and machineability. Their complexity is really fascinating. Even some common woods like oak can be either easy to machine or really a pain to machine depending on where they grow. (Some oak trees have so much silicates in the wood that they are pretty much commercially worthless because they dull cutting tools real quick.)

In the end John found a way to save a few bucks and I appreciate his post. i expect I will hone or sharpen my disposable planner blades a few times before throwing them away. Thanks, John D.
 
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