Can't use a Woodmaxx WM-8H below freezing ??

[TmbrWlkr]

I have been getting close to pulling the trigger on a PTO powered chipper for my Kubota L3400.

I called the Woodmaxx factory today to talk about there "scratch and dent" sale.  During the conversation I was informed by the rep that you can't run these machines below freezing because the A8 steel in the knives will break/chip etc.  Has anybody with with one of these Woodmax chippers experienced this.  Is there a workaround?  That severely bummed me out because it eliminates about 3 months out of the year of use for me. :'(  They don't offer any other knives .......

Would love to hear from you chipping guys

[moosehunter]

I have a Farmi. Have chipped well below freezing with no problem. Don't know what kind of blades are in it, would assume OEM but don't know 100%.
mh

[richhiway]

I use mine in the winter. Probably not much colder then 32 during the day though. Never had a problem.

Woodmaxx 8 inch mechanical feed chipper. - YouTube

[TmbrWlkr]

Thanks - I kind of geeked out when they told me about "below freezing" and did a deep dive into A2 steel properties ( the tool steel they use for the knives) I.E. -  DBTT ( ductile brittle transition temperature ) and MDMT (minimum design metal temp).  Then called Woodland Mills to see what they had to say, then called WoodMaxx back and asked for their blade mnftcrs' # and told them I was now Seriously considering their competitor ........ Then got an answer back that I could use it below freezing, But, I risked breaking knives ...........whew .......!!!!!

All that as I realized I would probably be only using it in the mid 20's F  and not very often at that.

So now I am waiting for them to have one available.

[mike_belben]

If its only one or two knives and youre that concerned, just warm them up a bit with a bottle torch before you feed in a batch of wood.

[Old Greenhorn]

Your first post says "A8", your second post says "A2" which is it? I would think A8 although I would have picked A6. A2 in generally used on the very precision cutting dies and not very impact resistant (possibly why there is a temperature issue).
 Actually I am pretty surprised to hear they have picked a steel that won't function safely below 32, but impressed that they are upfront about it. Obviously the manufacturer is keen on how their machines work, but you would think after running for a few seconds those hammers would be 'warmed up'.

[TmbrWlkr]

MY Bad!!! - good catch - it is A8.  Picked for it's combination of "toughness" and durability ( and resharpen ability) I couldn't actually find a DBTT curve online - but if it follows other A carbon tool steels there is not really an issue till below 0.

Thanks again for the input. 

[Old Greenhorn]

Reflecting further in the light of day (and the absence of adult beverages) I believe the A8 is somewhat tougher than the A6 which is quite tough. A2 would be unsuitable, I think, because it tends to be a bit more brittle. The "A" by the way signifies Air Hardening methods are used (as opposed to quenching in water or oil). I am now wondering how thick the blades are on that machine, because I could see where if they are on the thin side (under 1") they might be brittle at cold temps. The only blade like that I have worked on was doing resharp work on tire grinder blades, but they were honkers, about 3" think and around 18" diameter with a 5" bore or so. Those puppies were hard and tough and getting them up on the grinder was not a lot of fun. ;D
 Good luck with the machine.

[John Mc]

I wonder if the concern about operation below freezing is more about the wood than the steel used. Chipping fully frozen green wood could be like throwing a handful of rocks into your chipper.

I also would not be surprised if the manufacturer's customer service or sales reps actually have no idea WHY operation below freezing is a problem. They are not metallurgists. They know what someone passed along to them: chipped teeth. They may have no clue whether this is due to the type of steel used, or the fact that chippin hard-frozen wood is like chipping rocks.

[TmbrWlkr]

When I was at Forestry School - the dark ages - I remember we were outside  in a lab with our required axes, and my roommate chopped into a frozen hemlock knot.  Took a 1/2 a quarter shaped chunk out of the axe blade. Granted it was colder than a witches teat - probably single digits or less. The instructor's comment was "what brand is that, a Plumb?  Yeah, they'll do that".
So, I am aware of the affect of temp on steel "ductile-ness" and frozen wood. Think I am comfortable running the machine in the 20s. Warming the blades is a good suggestion though, thanks.