Insert Tooling Pros and Cons
Insert tooling is handy for the machine operator, but can cause trouble for the finisher. September 17, 2008
Question
Hi I’m buying a 24" planer for my shop and I’m not sure what’s better, the regular knives or the spiral head with indexable inserts. Which you recommend?
Forum Responses
(Solid Wood Machining Forum)
From contributor J:
In this case I would prefer inserts. Picture this: You are having a good production day, getting a lot done, great finish, etc., then you hit a nail, staple, rock, whatever. If these were standard knives you would have to go through an extensive re-grind process, or replace them all together.
If these were carbide inserts all you have to do is loosen one set screw, spin the insert to a fresh side/or replace if it is broken, and fire the machine back up, you might lose a minute, compared to an hour or more with straight blades.
Hope that helps, I realize initial cost is more to get set up with inserts, but you will make it back quickly avoiding headaches and lost time.
From contributor A:
Contributor J makes a very good point. The other thing you need to consider however is the type of finish you desire. If you need a really nice finish then stick with straight knives. The inserts will leave stripes as wide as the inserts the length of the board. If this is not an issue, by all means go with inserts. It's quieter, lasts longer and I believe uses less horse power.
From contributor E:
It's been almost two years ago that I converted my PM24 to a Byrd Shelix head and I love it. No more time wasted sharpening the old knives. I've run thousands of bd ft of hardwood and except for something that nicked a couple of the inserts which were easily replaced, I've not had to do anything to the inserts. The finish has been fantastic. Run the wood a couple of passes through the wide belt and it is ready for finish. I'd rather fight than switch back to the old blades.
From contributor F:
I've got the inserts on my 20" and they are great. I have had the planer just about a year now and with several thousand bd ft of mostly maple through it, and have yet to change (turn) the inserts). The surface quality is superior to straight knives in respect to tearout in hardwoods like maple, and the slight lines that are left by the carbide are easily sanded out. In my shop everything that comes out of the planer goes through the sander anyway so for me it's a non-issue.
From contributor R:
The down side that I have found is the sheer amount of time it takes rotate to sharp sides as well as the common complaint of snapping off torx bits while resetting them. On the upside, it also tackles great problems like ropy grain mahagony and burly type grains. I haven’t sold a set of planer knives in a while, but the initial investment in the inserts is around $200. To me, it’s well worth the money and time.
