Home made 72" chainsaw mill

[stihlatit]

Here's the requested photos of the mill. Again, this was rigged together from 99% free materials so it ain't pretty. When I get around to building v2.0 I'll be sure to post it up here.

Meanwhile, I need another 48+er to tear into. Any leads? :greenchainsaw:

Thx for sharing Aggie great job.

 

[SmokinDodge]

Yes, very nice work on all of it.

 

[aggiewoodbutchr]

What improvements do you intend to make on the next mill over the current setup?

The current setup mounts directly to the bar similar to an Alaskan. With a bar this long there is a considerable amount of force applied to the bar and mounts. I'm a bit concerned about potential damage to the bar from the weight of the 084 powerhead hanging from it. Also, there is a noticable amount of sag in the bar beween the supports. The next one will mount directly to the powerhead similar to GB's mill but in a manner that will require only a chainsaw wrench to adjust the chain tension. This should allow me to beef up the way the entire rig supports itself with the goal of reducing vibration and improving quality and performance.

One minor change to the oiler will be to swap the ball valve with a gate valve. The ball valve tends to vibrate to full open when in opperation.

The powerhead will be sent to a hotsaw builder when I can afford it but I haven't decided to whom yet. I really don't wish to open that can of worms here.

Meanwhile, help! I'm out of logs!

 

[casey v]

Hey aggiewoodbutchr,

How did you connect the hose of the aux. oil to the bar? Can you post a photo of that? I would like to make one myself and I am curious how you did that.

Thanks Mike

 

[Big Woody]

the things heat up and actually become harder

Not to be impolite but I'm familiar with work hardening

Generally when things heat up they get softer and the flow stress reduces. Work hardening is due to deformation which makes the yield (flow) stress increase. If you repeatedly bend a paperclip back and forth it work hardens and it also heats up due to the internal frictional energy dissipation from the repeated deformation. However the heating does not cause the hardening.

 

[Full Skip]

This was done on a drill press with it set at 300 rpm (lowest speed) and liberal amounts of cutting oil. Not to be impolite but I'm familiar with work hardening.

The alloy GB uses to make their "titanium" bars apparently is as hard or harder than HSS, cobalt and titanium alloy bits available at the borg. I could have ordered a carbide bit but I'm not that patient.

No offense taken.

I thought that I was familiar with it too when I drilled at 250 which was the lowest speed I could go. It was way too fast. You need to drill at 70 or you just fry bits.

 

[aggiewoodbutchr]

Hey aggiewoodbutchr,

How did you connect the hose of the aux. oil to the bar? Can you post a photo of that? I would like to make one myself and I am curious how you did that.

Thanks Mike

I'll get you one when I get home. Basically I have a hole in the top of the nose guard to force fit the oil hose into. The oil floods the end of the bar and flow rate is set to where it stays wet but not pouring over. Most of it is probably slung off but enough makes it into the chain at the edge of the bar and through the factory lube port that the chain stays wet all the way through. I've experimented with several oils and I have found that cheap 5w-20 works best. It flows easily and I put enough on it to not have to worry about how well it sticks. With this and the primary oiler (with regular bar oil) combined I have not had a problem with over heating (except when I'm a bonehead and forget to turn it on).

Expect to use a lot of oil and fuel when making cuts like this. When milling these slabs this rig used a full tank of gas, primary oil and about 1qt of secondary oil per cut. However, it's a small price to pay considering what you're getting.

PS- If anyone has any suggestion how any of this can be improved, please share.

 

[aggiewoodbutchr]

Generally when things heat up they get softer and the flow stress reduces. Work hardening is due to deformation which makes the yield (flow) stress increase. If you repeatedly bend a paperclip back and forth it work hardens and it also heats up due to the internal frictional energy dissipation from the repeated deformation. However the heating does not cause the hardening.

You are correct. Improper use of terminology on my part.

 

[aggiewoodbutchr]

No offense taken.

I thought that I was familiar with it too when I drilled at 250 which was the lowest speed I could go. It was way too fast. You need to drill at 70 or you just fry bits.

The problem I was having was the cutting edges of the bits were breaking off almost immediately. I'm don't doubt bit speed is a big factor in this but I'm curious how hard this bar is compared to a HSS bit. Maybe if a machinist is reading this they can enlighten me.

 

[coveredinsap]

It depends on the alloy. I've got a small forge, and I've encountered some alloys, specifically on a .50 cal musket barrel blank (brand new) that would immediately 'work harden' to an incredible degree just from the heat of trying to cut it by hand with a hack saw. The stuff would cut fine initially, then turn harder than superman's kneecap as the metal heated up from the cutting action of the hacksaw.

It makes sense though that they would maybe use a similar alloy for chainsaw bars...as they both (gun barrel and chainsaw bar) need their maximum hardness when subjected to heat.

I haven't tried to drill a chainsaw bar yet.

 

[sawinredneck]

I am not sure what the hardness is of a chainsaw bar, I am sure it's hard. I would give up on the HSS bits and try cobalt, if you can find them TIN cobalt even. If it work hardened go o the hardware store and by the cheap concrete drill bits. The ones for a rotary drill, not a hammer drill, they have carbide tips and will usually cut through anything if you can provide enough pressure. The next step is a solid carbide drill bit, very expensive and way too brittle to be used in a hand drill. Also try step drilling, star with a 1/16 then a 1/8 then a 3/16... so on, just take a little at a time, less heat to work harden the material.
Hope that helps a little,
Andy

 

[flht01]

Drill Speed

... You need to drill at 70 or you just fry bits.

I just bought the aux oiler for my alaskan mill. The instructions stated 80 rpm max for the drill speed, a lot slower than my press will run. I drilled 2 holes 5/16" dia using an air powered hand held drill and a standard hss bit. (Only took one bit and cutting fluid). I ran the drill just fast enough to turn the bit, results were slow going but better than I expected. The recommended 2 holes to allow flipping the bar Seems they like to see the oil fed in the rail right ahead of the sprocket to make sure the roller nose stays lubed.

 

[coveredinsap]

Seems they like to see the oil fed in the rail right ahead of the sprocket to make sure the roller nose stays lubed

Makes sense. I just saw recently where Husky also recommends greasing the bar nose sprocket (with special grease) before every use. I just stick the tube up to the pinhole in the bar, getting a flat seal...and squeeze while rotating the nose sprocket with my finger.
I wonder how many people grease the nose sprocket every time they use the saw?

You can usually reuse those HSS drill bits after they're trashed too. Just sharpen/reshape the tip on a belt sander and quench it in water to harden it back up.

 

[aggiewoodbutchr]

... I would give up on the HSS bits and try cobalt, if you can find them TIN cobalt even.

I tried all three of various sized with the same results. At this point I don't intend to drill any more large (3/8") holes in the bar but this is good for reference. I may open up the factory holes at the sprocket eventually but, for now, the factory 1/8" holes are working fine.

I seems my definition of slow is still way to fast. I'll hand drill them or find a pulley to slow down my drill press even more next time.

 

[aggiewoodbutchr]

You can usually reuse those HSS drill bits after they're trashed too. Just sharpen/reshape the tip on a belt sander and quench it in water to harden it back up.

I have a Bit Doctor that works pretty good. It doesn't get them back to factory standards but they work.

 

[aggiewoodbutchr]

Update

I was asked in an email if I do anything special to keep these slabs flat. I finally got around to taking a picture.

I used hardwood dunnage and 1/2" threaded rod to make clamps big enough to press the entire stack together. So far, it's working.

 

[stihlatit]

I was asked in an email if I do anything special to keep these slabs flat. I finally got around to taking a picture.

I used hardwood dunnage and 1/2" threaded rod to make clamps big enough to press the entire stack together. So far, it's working.

looks good Aggie.

 

[ShoerFast]

The problem I was having was the cutting edges of the bits were breaking off almost immediately. I'm don't doubt bit speed is a big factor in this but I'm curious how hard this bar is compared to a HSS bit. Maybe if a machinist is reading this they can enlighten me.

AggieWoodButcher

As you should be having a problim drilling the bar, your drilling a finshed proudect, I'm no machinest, but it's very possable the bar is a 5160 or an L-6 steel ( like a truck coil spring or a band saw blade) .60 carbon. To HSS or M-2 steel at .75 carbon , but there is a chance that the heat-treat of the bar has a case-hardened surface thats very hard and irreguler grained,,,,, bit killer.

If your ever at a trade show were they have magic HSS drill-bits, that pop holes in a file just as fast as they pull the handle,,,,, take a close look at the color of the file, it's a dull gray-blue Annealed file!

If you feel lucky, you could wet rags to keep the surounding area cool, and dounut so to speek the area you want to drill, and heat it with a tourch till red and back the tourch slowly away, I would need to feel real lucky that day.

Not doubting that there arnt drills that would cut just about anything, half the fun is the task it self!

Kevin

 

[carvinmark]

I was asked in an email if I do anything special to keep these slabs flat. I finally got around to taking a picture.

I used hardwood dunnage and 1/2" threaded rod to make clamps big enough to press the entire stack together. So far, it's working.

Now that's some serious stacking there....wish I had that much patients,looks real nice!

 

[flht01]

I was asked in an email if I do anything special to keep these slabs flat. I finally got around to taking a picture.

I used hardwood dunnage and 1/2" threaded rod to make clamps big enough to press the entire stack together. So far, it's working.

Thanks for the pictures, let us know how the drying process goes. Oh, and pict's of the projects you'll use these on.

Kevin