Planer knives

[Chuck Hancock]

Help me out here. I'm in the market for a planer of my own. I've been using a DW733 for about six years at work. It's been an acceptably reliable tool over that period of time. One of it's better features is a set of knives (two) that can be resharpened. I keep three sets in rotation and send one out for resharpening every eight to ten weeks, at ten bucks a pop. My research in current planers has revealed a dominant trait in what's being called "disposable" knives. The deal seems to be a set of (commonly) three knives that are each sharpened on two sides and are non adjustable on the cutterhead. When each side has been dulled, toss 'em and buy more. SERIOUSLY? So.. I've had my eye on a Delta 22-590, but this also appears to possibly be a throw away model, though no one mentions this. It's all about "quick change" and "ease of use".. etc. Does anyone know if the 22-590's knives can be resharpened? And if they can't, can you share a bench top planer model that does have resharpenable knives? I'm obviously speaking of traditional knives here, not indexable carbide insersts. Thanks in advance.

[Chuck Hancock]

Bump. Anyone?

[Kirk Poore]

I've heard of people sharpening disposable knives once, then they're too narrow after that. I've never done it, though.

It sounds like you're getting a good deal on sharpening, at about 42 cents per inch (costs me 50 cent/in where I go). How many sharpenings does a knife get? Let's say you get 5 sharpenings per knife and your knives cost $40 per set, that comes out to $90 for six uses, or about $15 per use.

My old DW 734 cost like $50 per set (3 knives), and had two edges, so that came out to $25 per use. (Note--I had a two knife Delta before the 734, and the Dewalt knives didn't really last much longer it seemed so I'm not incuding that in the equation.)

A significant savings, not counting the time required to drop the knives off and pick them up from sharpening. But for somebody changing knives twice a year, maybe $20 in savings isn't enough to overcome the inconvenience.

Kirk

[Van Huskey]

Not directly on point, but it will give you a bump.

With that amount of usage I suggest you consider a carbide insert spiral head, it should save you money and a lot of time in the long run.

[Chuck Hancock]

Thanks fellows. Kirk, I'd guess I'm on the 5th or 6th sharpening on the oldest set. Maybe 4th on the newest. The holes/slots for mounting the knives are generously slotted and I don't thing I'm near the point where I'm going to worry about the integrity of the mounting interface. I should get at least a couple more sharpenings on each set before I start scratching my head. If I get eight sharpenings @ $10 per plus $40/set to purchase, my cost is $13.33 per set. I think, Van, that the spiral cutter w/ indexable inserts is the only cost effective alternative. I find the relentlessly increasing disposable predilection of our society kind of a bummer. Thanks for the input.

[glenn bradley]

What Van said. If you can dull a set of knives in a few weeks, you would pay for a spiral head in short order. And at $10 a shot . . . even if that is per pair, the two sided throw-aways (6 edges) aren't much more and you don't have to drop off and pick up. I'd go carbide insert and just never look back.

[Peter Quinn]

Thanks fellows. Kirk, I'd guess I'm on the 5th or 6th sharpening on the oldest set. Maybe 4th on the newest. The holes/slots for mounting the knives are generously slotted and I don't thing I'm near the point where I'm going to worry about the integrity of the mounting interface. I should get at least a couple more sharpenings on each set before I start scratching my head. If I get eight sharpenings @ $10 per plus $40/set to purchase, my cost is $13.33 per set. I think, Van, that the spiral cutter w/ indexable inserts is the only cost effective alternative. I find the relentlessly increasing disposable predilection of our society kind of a bummer. Thanks for the input.

I just ordered a byrd shelix head for my 8" jointer. Maybe the planer is next. When I figured out what my 3Z jointer head was costing me per instance for sharpening, and added in how much I love setting knives on a 1-10 scale (that would be a negative number), I decided I had changed my last set of straight knives. Done with it. I've probably bought the byrd head twice by now in grinding charges.

Way off point, but we have a bunch of quick change machines at work, terminus heads mostly, and those darn knives are expensive. You get one or two sharpenings per set, so its not as bad as some. But in the commercial environment, where you can run a huge dollar value of lumber thorough a machine in a short period, and you have a variety of different employee's maintaining machines (read "monkeys beating the tools") it only makes sense to use a system that is quick, simple, and fool proof. Lost time equals lost money. I could imagine that for a hobby shop, at some point if time is scarce, the quick change system begins to get real attractive. Do you want to spend your scarce time working wood or setting up planer knives?

From a "metal used" stand point I'd bet the disposable knives and traditional knives run pretty close over the life time of use. You wind up recycling a good bit of the steel on traditional knives, and they are a good bit thicker. I guess I find the disposable society pretty disheartening generally but this is one case where I find a real logic to using a disposable item. I'm told our old knives go to a junk collector that collects and sells metal for scrap, so it stimulates the local economy in some small way too!

[Rod Sheridan]

After decades of adjusting jointer and planer knives, I bought a Euro combo with double sided indexed knives.

The cobalt knives last longer than my old knives did, and the cost is about the same for replacement versus grinding.

Also I can change the knives in 3 or 4 minutes, no adjustment required.

I haven't felt the need for a carbide insert head yet..........Regards, Rod.

[Ted Wong]

Most lunch box planers use disposable knives. On a makita 12" planer a set of two knives (4 edges) costs about $40.00. Compared to the initial costs of a reusable blade and subsequent sharpening and the time it takes to reset them I'd say the disposables are a bargain.
Yes the throw away aspect is wasteful but I look at it this way, sharpening a reusable set turns metal into unusable dust leaving about 60 - 65% of the original blade height. When I pitch a disposable knife into the scrap bin most of the original metal is still there.

[Chuck Hancock]

Hmm, so it's looking like there just ain't no resharpenable knives on the market any more. Expensive carbide insert head or throwaways... Thank you all for your input.

[Steve Schoene]

If your time is worth anything, the dramatically reduced time to change blades is a big plus for the disposables. Change in a few minutes, no jig needed. The mounting still does allow you to shift a blade enough to eliminate a premature nick in the blades.

[michael case]

I've, been cheating. I have been sharpening my disposable dewalt knives on my tormek. There is no adjustment when setting these knives. Because of this you have to make your passes over the stone perfect, so that the new edge is parallel to the original. You also have to take just the same amount off each knife. Also you can't take much off. Needless to say, you can't send them out for this kind of sharpening. You have to do it yourself and can only get away with it on a slow and very accurate wet grinder like the Tormek. I get two sharpenings to a side for a total of four. This would equate to $40.00 of sharpening so the $50.00 cost of the new ones is not as bad as it first appears. Also installing is a breeze because they are indexed and there is no adjusting - just drop them in place on their indexing pins and tighten them up.