economics of planer knife changes

[Tyler Davis]

I am faced with replacing straight knives on my 15" Grizzly planer for the first time.

I was looking at the Dispoz-a-blade system which is a $250 initial outlay, then $45 for two-sided replacement blades. This is what came in my jointer and I really like it, but the previous owner paid for the system (initial cost).

The standard blades are $50 for a single-sided replacement set (assuming I don't resharpen them)

doing the math, the Dispoz-a-blade system starts saving me money after about 9 knife changes

how often do you all replace/resharpen your blades? About how many board feet do you run before you start to notice poor cut quality?
Assume I will be working a mix of oak, mahogany, maple, and other standard hardwoods.

[Thomas S Stockton]

My question is why would you not get your regular blades resharpened, that is what they are designed for. Of course if you stick with this set up you should get a second set that you would use while the other is being sharpened.
Never used a disposa blade system but people I know who have like it and the cost of the blades is about the same cost as 2 sharpenings so the initial outlay should pay for itself after a few blades changes from the amount of time you have saved. The other thing I would look at is if they offer the blades in different types of steel, I use m 42 steel and really like it, seems to last longer than HSS and isn't as costly as carbide.
I have a tersa head on my jointer and I really like it, the blades cost about $100 for a two sided set and it takes about 2 minutes to change them out.
Tom

[Steve Schoene]

I don't quite understand your math. You have the regular blades sharpened. That costs about $0.50 per inch, or $22.50 to have the knives sharpened for a three bladed planer. That part compares to 22.50 per edge on the disposable. So the running costs would be the same, between the two. But, the regular blades need replacing from time to time, adding $50 to the cost of using regular blades. Depending on how many sharpenings are possible before the blade must be replaced will determine the pay back period for the initial set up for the disposable blades. Since money is valuable, a payback period over say 5 years max, isn't economically feasible on that basis alone. BUT...

And, it is a big BUT... If your time has any value the disposable blades are changed in very much less time than regular, since the regular blades must be carefully aligned to each other to achieve a good finish.

I wonder about $45 for a set of the disposables. I paid less than that--about $35 for a three bladed double edge set that are standard for my Hammer 16" J/P combo last year.

[Tyler Davis]

thanks guys

I was avoiding sharpening because I was under the impression it cost almost as much as new blades once you figured in the shipping cost. What company should I be looking to for sharpening?

I will also look into the M42 blades for longevity - who sells them?

I was planning on using the factory knife-setting jig to ensure the knives are parallel to the table and all at the same height. I was under the impression that setting knives in a planer was easier than a jointer because the planer is less sensitive to height variations (simply reset the depth indicator to the new knife height).

[Rod Sheridan]

I was under the impression that setting knives in a planer was easier than a jointer because the planer is less sensitive to height variations (simply reset the depth indicator to the new knife height).

Hi Tyler, planers are very sensitive to knife height changes since the pressure bar and chip breaker heights are referenced from the knife height.

If you change your knife height, you have to reset your pressure bar and chip breaker.

Regards, Rod.

[Jim Barrett]

thanks guys



I was planning on using the factory knife-setting jig to ensure the knives are parallel to the table and all at the same height.

Tyler,
The knife setting jig will help you to establish the knives are parallell to the cutter head...not the table. Now if the cutter head is parallel to the table....then eureka...you got it!
So you need to make sure the cutter head is parallel to the table first...for a 15" planer I would say .003 would be acceptable.

Jim

[Steve Griffin]

Every tool in my shop has two sets of blades.

My two sets of planer blades in the 20" planer have lasted 9 years in a shop with 1-3 guys working. A set gets sharpened about every 2-3 months. If you don't run over a nail or something, they last a very long time and can be sharpened many times.

The idea of disposable blades sort of bothers me, and I'm not sure it is worth any savings, if there is any.

I did find a local hardware store that sends blades out for customers. This is a welcome relief from packaging and mailing out stuff yourself, so you may want to search for a similar service.

-Steve

[Bruce Wrenn]

Check with Global Tooling for a set of knives. About $40, plus shipping. With freight both ways, they are competitive with sharpening.

[Curt Harms]

thanks guys

I was avoiding sharpening because I was under the impression it cost almost as much as new blades once you figured in the shipping cost. What company should I be looking to for sharpening?

No first hand experience but Scott Whiting gets good reviews and he's an SMC member
Scott's Sharpening Service

5214 W Luke Ave Ste 7
Glendale, AZ 85301
Phone: (623) 931-0633

[Danny Burns]

You seem to running a lot of hardwoods, so blade wear will be high.

IF you are running large volumes of hardwood, then the real savings come from not having to spend too much time changing blades.

Hit a knot, nail, or other debree, well before dulling the blade, and you will be glad you have a quick change system.

Downtime is probably at a minimum with the Tersa system, and so I look into the cost of using it, as there are more than one type a knife available for the cutter-head.

[Barry Richardson]

I'm not familiar with Tuscon, but here in west Phoenix, I can think of at least three saw shops that sharpen locally. I'm sure there is one in Tuscon. Google is your friend.:)

[Tyler Davis]

the Tersa system requires that you buy a complete new head, right? I'd like to avoid that cost

I will buy a set of straight blades from Global Tooling and see how long it takes me to change the first time. If it's a huge pain, I will invest in the Dispoz-a-Blade due to its auto height-setting

thanks for the advice, all