Those trying out the 4/39 Degree blade profile

[octam1]

To Customsawyer and any of you other guy's trying out the 4/39 degree profile for blades, im interested in you feedback as to how well they have been performing for you guy's and have they been holding up well?

I switched over to the 4/34 and Turbo7 profiles and am relatively happy with performance, altho the 4/34 profile is quite a bit slower cutting when we use them vs the T7...

Alot of my sawing is on reclaimed beams for customers here in California and its not unusual for me to use 80 to 100 blades in a 5 day week, most of my customers lately have been ones that turn out to be pretty hard on blades to say the least!

I have lots of 4 degree blades to resharp and just looking for opinions before I pull the trigger on a 4/39 wheel for the sharpener...

Any info and discussion would be much appriciated! Thanks!

[YoungStump]

I used the 4/39 some this winter, I didn't use it enough to say I've tested it extensively, as I've gone back to the 7/39 now that I'm not dealing with frozen logs, but it seemed to perform very well in hickory. There are others who've used it a lot more than I have with good results.

The 4/39 wheel is designed to change the profile of the 7/39 to a 4/39, I don't believe it will work with the standard 4/34 profile, I'm sure Richard from Rixsaw would be able to tell you for sure.

[customsawyer]

I have only used it on about 25 blades. I am very pleased with the way it performs on hardwood. Haven't tried it on soft wood yet. It is a little slower in 20" and wider cuts but you don't have to slow down for knots and get a more accurate cut. If it does well in soft wood I will probably use it for everything.  If you are going through that many blades I would say get one. I like the Turbo 7/39 blades for the cutting speed but when it starts to get a little dull it seems to start waving pretty fast. The 4/39 is a lot more forgiving.

[WH_Conley]

I just finished up 27k of junk Walnut. Some of the logs were 3 years old, very hard. I normally use 10 degree blades and they just wouldn't get it. They 4 degree would cut straight and last much longer. I tried them on Yellow Poplar today. A little slower than the 10, but less worry about dipping at the knots. Haven't tried them on Oak or Hickory yet.

[Cutting Edge]

I don't believe it will work with the standard 4/34 profile

YoungStump is correct.  The Rix-Saws 4/39 CBN wheel should only be used for the 7/39 profile blades.

[octam1]

I noticed the 4/39 is for use on the 7/39 not the 4/32 and im all good with that as well, we currently have hundreds of Turbo7's stockpiled and can convert some of those... Im really happy with the performance of the Turbo7 altho we have noticed in hardwoods we just dont get the same runtime on them, hence the interest in the 4/39 profile... Hoping we can increase our feedrate with the 4/39 like with the Turbo7's and get a little better run time out of them!

Thanks everyone for your input!

[caveman]

I have been reading quite a few old posts lately and came across a couple that were about grinding 7° bands to 4° when sharpening them.  I was using some 7/39, 1 1/4", .045 blades to saw some longleaf after I ran out of sharp 7°, 1.5" blades.  The 7/39's cut pretty well in clear longleaf pine but when I got into some knots, they would wander.  Started out with one today and when it started to deflect when hitting knots, we pulled it off and put on a re-profiled 7/39.  

A week or so ago I took the guy who sharpens our blades several 7/39's.  He suggested sharpening them to 4°, which I was all for.  This morning we tried one.  It was not perfect in knots but it was a good performer.  We were able to cut a 16' lightered cant dead flat.  It was good enough that we quit cutting boards out of it and will try to sell it as a mantle or shelf.  I called Earl, the retiree from a well known sawmill company, and asked him to sharpen the bands I took him Monday exactly the same.  I don't think I have a picture of the lightered cant but the boards on the right of the stack are full of pitch.