Drilling a Chainsaw Bar

[Coon]

I got a couple of questions for some of the guru's here. 

I am in the process of building a chainsaw mill and will possibly need to drill a hole in the bar.  What precautions do I need to make in doing this?  Is the material that the bar made of really hard?  Will heat be an issue while drilling? I can keep it cool with cutting oil or something if need be.

 I need this mill within the next couple of days to remove a couple of yard trees for a friend.  The yard is completely fenced in and he does not want to remove any fence sections to get the logs out so..... next best thing-- chainsaw mill.  He is not worried about the sawdust on the lawn.  I need some 12 foot long 3x6's and various other dimensioned lumber so..... here's my chance... 

Brad.

[VT-Woodchuck]

Use oil and a sharp bit and you should be okay. I've done several with good results.

[bandmiller2]

Turn the drill as slowly as you can.Best setup would be a drill press or milling machine set at very low speed,cutting oil good pressure on the bit.High speed drill motors tend to harden the steel under the bit it just glazes over.Frank C.

[Toolman]

I would recommend a cobalt bit. Start with a smaller hole then work your way up to the desired diameter. This will greatly reduce the amount of heat. Low RPM and cutting oil also.

[coastlogger]

I read in a book years ago that the secret is to lie bar on top of another old bar while drilling, that way the heat dissipates to the other bar which is somehow better, otherwise it may harden just as you are breaking thru, due to high heat and air cooling(or something). This method does work, not sure if its really necessary or not.

[Coon]

Thanks for the replies guys.  I am still not sure if I will need to drill the bar but may figure it out olater in the day.  As for now I have to go move thounsands of bushels of grain around to keep it from heating.   

Brad.

[ely]

i can remember two things in my past that were very toough to drill a hole in. one was a chainsaw bar, the other was the piece of flat metal that keeps the door from swinging too far open on a 1961 gmc pickup truck.

finally got them both done but not without a lesson or two from dad on which tools were ok for me to use and which were not.

[Gary_C]

There is a lot of difference between manufacturers as to the hardness of chain saw bars. For example on harvester bars, the GB bars are much stiffer and harder to bend than the Oregon bars. However you can straighten an Oregon bar easily, but you can't say the same about a GB bar.

So the same can be true about drilling. Some may be easier to drill than others. You just have to try and see what bit will cut them.

[olyman]

know the cement bits that look like a reg drill bit??? have the carbide pieces brazed to the tip of the bit??? they will drill that bar. not sure how small they come. also, when you drill, use water.oil is a LUBE,hence,the bit will "float" a bit on top of said oil. water will keep it cool,and the bit will be right against the steel. done it,works.sounds strange,but aint.

[nomad]

     In a pinch, water will work better than nothing.  If you have to use water, use enough to keep it flooded.  A better bet would be to use a metal cutting lube. "Tap Magic," or something like it.  With that, you don't need a lot; just enough to keep the surface wet.

     Olyman is right; don't use a regular lube oil.  You'd be better off cutting dry.

[Magicman]

Diesel/kerosene works well.

[Coon]

I never had a chance to get the hole drilled today due to grain heating in the bin.....  had to rotate it to cool it down. 

I have a small bottle of cutting oil that I will use if I don't try the water thing.      I even have an old bar I can try on first too.  Same brand and everything.

Brad.

[sawdust]

Coon, I have drilled lots of holes in bars for my jigs. I use a cobalt bit and salt water. 1/4 inch first and only hole. How big do you need? I only use salt water because that is what saline bags have in them.
David

[TwinCut]

With 23 years of machining experience I know what you are up against. Here is a simple trick. Resharpen a regular drill bit with a "Flatter angle". A brand new bit will have a 118 deg included angle. Regrind the drill to about a 90 deg or slightly less angle, and spin it at about half of what you normally would, and you will be amazed at what you can drill. There is an art to sharping a drill, but with practice it will work like a charm.

[jdunmyer]

I once drilled a bar with a carbide burr, as I didn't have a carbide drill. A regular bit just skidded on the bar surface. The concrete drill bit that's carbide tipped will also work.

[Coon]

I am not to sure yet as to the size of hole that I am going to need.  Plan is to put an auxillary oiler on the mill.  As many of you know... I like to build things like this for myself and to suit my own needs. 

Brad.

[Tom]

I wonder if you could punch one through there with a 30/06? 

[TJB]

I took my bar to a local machine shop and gave him 5 bucks to drill a couple of holes through it

[sawdust]

Coon, if you are approached by Direct energy to consolodate your gas and electric bills. Chase them off. The thieving buggers hve small print that will cost you dearly. pm me if you want details. Anyway to get this to the rest of the Canuckistanis on here?

david

 

[Gary_C]

Drilling that bar may not be as difficult as you think.

It will be best if you use a drill press, start with a pilot hole, and then drill to the size you need. Make sure you have a sharp bit, run at the lowest speed you can, and use cutting fluid. The cutting fluid, what ever kind you use, is mainly to prevent the piece from getting hot.

For this job, heat is your enemy. Once you get that piece hot, it gets very hard to machine.

If you don't have access to a drill press, you must keep that bit perpendicular to the bar you are drilling. If you move just slightly off perpendicular, that bit will grab and most likely break the outside corners off the cutting edge and then you are in trouble. At that point, it is best to get another sharp bit as you will have a long way to grind to remove those outside broken edges.

So just go ahead and have at it. 

[Coon]

Tom, I don't own a 30.06.  ......  But I do have a variety of other gunpowder propelled drill bits.....  The .300 UltaMag will do the trick or I could just bring out the "Iron Mule" which is a 45/70.  I would just have to figure out a way to prevent tear out. 

Gary,  I have my choice of drill presses to use.  I will see which one turns the slowest first.  Work is getting in the way currently but I am pretty sure I can find the time before the weekend. 

Just talked to my friend.  He now says there's not too much of a big hurry to get the trees cut.  He would just like to see the trees gone before it gets too cold out or we get too much snow.  Hoping to get them done this weekend.

Anyone here make their own auxillary oiler? How did you make it? Just need to get a few idears into this thick brain pan. 

Brad.

[Brucer]

I read in a book years ago that the secret is to lie bar on top of another old bar while drilling, that way the heat dissipates to the other bar which is somehow better, otherwise it may harden just as you are breaking thru, due to high heat and air cooling(or something). This method does work, not sure if its really necessary or not.

The steel in chainsaw bars is air-hardening, meaning if you get it too hot, it will get very hard just from the cooling action in the air. Most types of steel need to be quenched in liquid to harden them.

The secret is to keep the bar very cool. It's when you break through that the remaining metal gets very hot and then hardens. Lying it on top of another bar (or any piece of thick, flat metal) will draw the heat out of the one you're drilling before the temperature gets to the hardening point.

Any of the suggested methods for cooling with liquid will help -- just be especially careful when the bit is breaking through the metal.

Drilling a pilot hole is OK, but a small hole will harden just as easily as a big one, unless you keep it cool.

Using really hard bits (e.g. carbide) doesn't prevent the bar from getting too hot and hardening. The bits may cut the hardened metal without dulling, but why not save yourself the extra effort -- just keep the metal cool through the whole process.

[Magicman]

I wonder if you could punch one through there with a 30/06? 

If'n you kilt it with an '06.......how would you cook it

[PC-Urban-Sawyer]

I wonder if you could punch one through there with a 30/06? 

If'n you kilt it with an '06.......how would you cook it

If you use too high a speed to do the drilling it will cook (heat) the bar for you, course it will be a bit tuff... 

Herb

[Coon]

I think I woud BBQ it....  still tryin to figure out how long it'll take and what flavour of wood to use...   

Brad.

[nas]

I think I woud BBQ it....  still tryin to figure out how long it'll take and what flavour of wood to use...   

Brad.

Ironwood?

[woodsrunner]

I've done this very thing for my CSM. I had some folks on another forum tell me all these tricks to drill the bar. Everyone kept telling me you had to drill the hole thru the center of the bar sprocket. DON"T DO IT THAT WAY. I have yet to understand why everyone thinks that is the way to do it. This forces you to try to drill a hole thru the center of the sprocket bearing. Bearings are very hard. Why fight with it? Drill the hole behind the sprocket thru the bar only. Much easier.
You may lose a couple of inches of bar length for your csm, but, so what? Work smarter, not harder.
Scott

[btmsx]

I wonder if you could punch one through there with a 30/06? 

I know a toungstun core AP .50 BMG round will do it. Shot 3 in an old 24" husky bar at 50yrds.

[jpgreen]

These will drill through the bar like butter:

http://www.use-enco.com/CGI/INPDFF?PMPAGE=48&PMCTLG=00

Very slow RPM with cutting oil.

[woodsrunner]

Thanks for the link!

Scott

[shinnlinger]

I drilled my bar a few years ago and didn't have the benefit of all this insight.  I turned the drill press to 4700 and burnt thru 5 bits or so making a oblong hole.  At the time, I thought that was just how it is as everyone says it is tough, but feel like an idiot now.

[jpgreen]

Nothing that we all have had to learn at some point.

Drilling steel- always slowest RPM possible, with the most pressure possible until near the bottom of the hole, then lighten up as you break through so your bit doesn't get stuck.

Use cutting oil and a sharp bit. The goal is to get a nice continous chip feed on both sides of the bit.

Your bits will last for years this way.

[jpgreen]

Really you should not have to use a carbide bit on a bar. A sharp HSS bit will work fine.

Another tip on drilling steel for a deep hole, or blind hole is to not let chips build up. Clear the chips by bringing up the bit as soon as the flutes load up, or start to load up.

Chips- will make your bit "walk", and throw your hole off even a few thousands. Criticle for precision machining, but not for general stuff.

Center punch your spot first.