Shaper heads and steel knives

[Mark Bolton]

What are you guys who use these systems getting for life out of your knifes between sharpenings? I realize this varies with species, amount of material removed, and so on but a rough estimation?

We are going to be ordering some cutters soon and have been kicking around one of the CMT kits with the M2 knives as well. I have run moulders on the TS but was never very happy with the cutter life.

Thanks for any input,
Mark

[David DeCristoforo]

We are getting very high yield from high speed steel cutters. In truth I am not sharpening my HSS cutters any more often than my carbide cutters. I run mostly walnut and cherry but occasionally exotics. Hard maple beats the cutters the fastest but the HSS cutters can easily be re-sharpened "in house" whereas we have to send the carbide out. For "all day" cutting HSS will be a PITA but it for short runs (a hundred to several hundred feet at a time) will produce cleaner cuts (when sharp) than carbide.

[Peter Quinn]

I'd guess off the top of my head you can expect 5000-10000LF with 5/16" corrugated back HSS cutters before a real sharpening is needed depending on species, honing in house may be required in between. I think carbide will far outlive that, especially on some of the tougher species. For instance the flooring mill I worked in would regularly run several hundred thousand LF on the same carbide cutter stack before changing knives, running 125K LF per week average. The cutters got (2) 30 minute breaks on a ten hour day, as did the staff. You are unlikely to get that kind of performance from HSS. If you do mostly soft stuff like mahogany, walnut or poplar expect to be at the higher end of the range, harder stuff like maple, sapele, jatoba or such will shorten the life of HSS, as will dirty lumber.

In my home shop I have an Amana 40MM head that uses the same knives as the CMT insert set. I have yet to wear out a set of knives as my production is limited, but the knives can be sharpened, though they are so cheap it would probably be more cost effective to treat them as disposable. You can get a few of the more popular stock knives in carbide, and you can get blanks ground to a pattern in either carbide or HSS. With the HSS inserts molding runs in the hundreds of LF don't even put a dent in the sharpness of these knives, but you are limited to a maximum depth of profile of 5/8" which is the chief limitation of these 40MM systems.

[Mark Bolton]

Thanks for the info guys, I had no idea the HSS would run that long. We are doing molding runs in the hundreds of feet at a time. Small quantities. We do have a few runs of Hickory flooring that will have to be T&G. I had carbide in mind for this but perhaps I could get away with HSS and a few sets of knives?

We are new to the shaper but really eager to get at it. What is involved with in-house honing? Do you simply hone the back side of the knife or to you have to work the bevel and the back? I dont mind the idea of looking at the knives as disposable however I am really not a fan of wasting. If I could hone in-house a couple times and then send them out for resharpening at a reasonable cost...

The 5/8" depth wont work for alot we plan to do with the shaper but it may be good for the bulk.

More to think about, thanks again,
Mark

[Steve Clardy]

I hone the back side of my HSS molder and shaper knives with some 150-180 grit paper laying on a flat surface. I'll do that several times, then send them in for sharpening

[David DeCristoforo]

I sharpen mine with stones and slips just like any other edge tools. They need to be reground now and then. But if you are running a lot of hickory you might be better off with carbide. Hickory is tough on cutting edges. I agree about the "throw away" knives even though that seems to be the trend. But HSS cutters will last for many regrindings.

[Rod Sheridan]

I guess I'd run 300 to 1,000 feet of material with no issues using the CMT head.

Depends upon species, and whether you're running a feeder.

Feeders increase cutter life because you can calculate the feed rate, run some test pieces and then the knives run cooler and cut a thick enough slice.

When I worked in a shop we ground the profile, at home I just toss the knife if I can't touch it up easilly with a hone.

Regards, Rod.

[Peter Quinn]

Did you say Hickory? That is one of the hardest domestics species and will put you at the lower end of the cutter life curve for HSS, carbide might be in order anyway if you plane to do a lot of flooring. Make sure to get dedicated flooring cutters or insert knives with the proper geometry (back bevel on one edge, nail slot, eased bottom edge, etc) as standard T&G cutters for joinery make install a problem.

The machinist at work maintains the knives I use, several thousand profiles last count. He hones the flat face on a diamond stone, and occasionally tunes the profile side a bit with a slip stone or round diamond sharpening rod. For more serious sharpening they are sent back to the grinder where they are reground using the original template on a CNC machine. The cutters need to be pretty well balanced and perfectly symmetrical to minimize chatter.

[Mark Bolton]

Thanks again for even more info....

I cant say for sure but I at this point it seems some custom runs of flooring may be fairly common. Hickory will not be so common (I hope) but yes, I did say Hickory.

And for the feeder, yes, we just purchased a new shaper and feeder. Rod, based on your recommendations about slow spindle speeds we ordered a Jet JWS-35x5-1 and a PF-31 1hp feeder. I would love to have gone with an industrial shaper but I couldnt come up with anything used and needed to get one into the shop.

Mark

[Mark Bolton]

http://www.acetoolonline.com/ProductDetails.asp?ProductCode=AMA-SCS-1004&utm_source=googlebase


?

Mark

[Jeff Duncan]

For small runs your probably better off with the steel knives. Talk to whoever you buy your knives from and get their recommendations also. I use CG Schmidt and they recommended M3 steel for me for a current job consisting of rift oak and hard maple.
good luck,
JeffD

[Ron Bontz]

You may want to look at "routerbitworld.com" before you buy the CMT or Amana heads. Also I had a custom set of knives made from M3 steel and they worked well for the small run of cherry I had to do for someone. Good luck.