I've got a Stihl MS 271 with a 20 inch bar and I love using it to mill up logs into pieces I can use. I often run into larger stock that would really be easier with a longer bar. That said, the spec says my saw supports up to a 20 inch. I don't use it often so its not like I'm going to be running a 30 inch bar day after day on hardwood. Think a few hours a month max.

Is it safe for the saw if I put a longer bar on it?

  • I have a 36 in diameter oak that I would like to mill. I'm looking at a saw with 24 in bar.... But from the sound of this, I would need to look at a significantly larger saw. Would I be looking at a professional series?
    – Yue Chu
    Commented May 5, 2019 at 14:49
  • @Yue Chu Welcome to WSE. This is a question and answer forum and you have asked a question within another one. The proper way to ask a question is to start a new question in which you can make reference to any related question by including its URL. I have converted your question to a comment within the original question. Feel free to post your own question.
    – Ashlar
    Commented May 5, 2019 at 22:51

2 Answers 2


Generally I wouldn't recommend using a larger bar than is recommended. I think the biggest issue is you will burn out your saw.

However, there is one thing to think on that might make it more 'ok'. When milling with a chainsaw there are special chains (ripping chains) and bars you can use to reduce the strain on the saw. Like other blade, most chain saw chains are designed to cut across the grain, and when you use those to cut along the grain it takes more work for you and the saw.

My recommendation would be to talk with a stihl dealer and find out if you can go longer if you use the bar and chains for milling.

Found the following information about the mills you are asking about

The general rule is, the more power your saw engine has, the faster the cutting speed. Almost any engine that runs will cut, it just depends on how much time you want to spend milling your lumber.

General Guide for Chainsaw Power

Log Size - Engine Size

  1. up to 18" 55cc to 67cc
  2. 18" to 36" 68cc to 85cc
  3. 36" & larger 86cc to 120cc
  • Good call on the ripping chain. I was already going to buy one. My set up is with an Alaskan Chainsaw Mill so the extra length is as much to connect to the mill as it is to mill wider stock. I wonder if the bar length restriction is under the assumption that you're sawing stock that is as wide as your bar. If you're not, does the strain still apply?
    – Brad
    Commented Jan 19, 2016 at 2:29
  • @Brad Actually I think most of those set ups actually allow for longer bars. I'm sure that's what I've seen, but a good stihl rep should be able to help you better. But with a ripping chain I think you can get away with longer bars.
    – bowlturner
    Commented Jan 19, 2016 at 2:32
  • 2
    In addition to burning out the saw, I'd worry about catastropical failure. Often, power tools are speed tools in addition to power tools. Which means they have, and need, considerable power and speed after spinning up. Plugging too-big a chain (... blade, router bit, drill bit, etc.) may quite possibly cause the tool to tear wood to pieces rather than cut through it, or worse, stop apruptly with either the too-weak motor taking damage, or sending the machine tumbling around, or metal pieces flying all over the place as the powerful-enough motor brutally pulls the blocked piece through.
    – Damon
    Commented Jan 19, 2016 at 16:12
  • One should never underestimate the kick that a running power tool which suddenly locks can produce. It sure can easily pull the machine out of your hands, and having a running chainsaw fly through the room is a no-fun experience. But I wouldn't bet my life that it's 100% safe even if it's fixed in a table or other stationary structure.
    – Damon
    Commented Jan 19, 2016 at 16:16

Using the right chain (cross/rip)and a bar a little longer (next size up)with the chainsaw mill (or just regular cutting) wouldn't be a problem if you just remember to let the chain do the cutting and don't force/push to hard/fast... most break downs are from impatience and abusing the machine - it will let you know by requiring constant blade sharpening (dust vs chips) !

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.