Any pointers for drilling (milling) holes in bars for modified alaskan mills?

gunnarfan · Jun 20, 2011

I've seen it mentioned that to get to your chain easier (for swapping out etc.) that its a good practice to do away with the alaskan clamps and put holes in your bar to bolt it direct to the alaskan. Any wisdom on this process (things to watch out for etc.)? Links to where this is discussed (or has been discussed) are always welcome.

mtngun · Jun 20, 2011

gunnarfan said:
I've seen it mentioned that to get to your chain easier (for swapping out etc.) that its a good practice to do away with the alaskan clamps and put holes in your bar to bolt it direct to the alaskan. Any wisdom on this process (things to watch out for etc.)? Links to where this is discussed (or has been discussed) are always welcome.

There's been several threads on the subject, but good luck finding them until the search function is fixed.

You'll need a carbide bit. I use a center cutting carbide end mill, but there are other types of carbide bits that will work, too. A standard steel drill bit will just make a mess attempting to drill through the nose bearing.

A steel bit may or may not work to drill the other end of the bar. Some bars, like Oregon and Windsor, are not particularly hard, while other bars, like Carlton, are darned hard.

gunnarfan · Jun 20, 2011

Thanks for the heads up.

I was wondering why the searches weren't terribly fruitful. I've actually had to use google with the term and arboristsite in the search to get any real success (was looking up references to james mitchell's short log and timber building book...)

I have three bar sizes that I'm looking to work on. Will check the make on all.... i'm thinking all oregon.

john taliaferro · Jun 20, 2011

Oil lots of it ,their made of work harden tool steel , so if hesitate at all its over . Drilling and bolting made a big difference in mill its sweet now three min chain change .

srcarr52 · Jun 20, 2011

Carbide ball mills make short work of it. In a pinch I've made the pilot hole with a carbide ball bur in a dremel and then enlarged the hole with drill bits or a carbide bur.

gunnarfan · Jun 20, 2011

i'll see if my table top vari speed delta can handle it. i might have a spare junk bar to practice on. might visit a buddy with a real machine shop if i have to.

smokinj · Jun 20, 2011

gunnarfan said:
i'll see if my table top vari speed delta can handle it. i might have a spare junk bar to practice on. might visit a buddy with a real machine shop if i have to.

Try a little cold lard on a hot bit.

redoakneck · Jun 20, 2011

If you like to hunt mice with an elephant gun, or know someone who has one, WATER JET

hbohnet · Jun 20, 2011

I have also been trying to find info on drilling bars, I thought it was me not searching properly. One question, what size hole should you drill through the center of the sprocket bearing and are there any tips on not harming the bearing? thanks.

jimdad07 · Jun 20, 2011

I did mine (30" Carlton) with a masonry bit using my Delta bench top drill press. That worked out pretty good. I did 1/4" holes for 1/4" bolts, may seem small but so far so good.

srcarr52 · Jun 20, 2011

5/16" (1/2" head) so you can use a scrench to tighten them.

Here.... this will make drilling that bar very easy. Just a little cutting oil and a bit of pressure. Make sure to clamp the bar to the table because movement will shatter a carbide. It's also best to put a piece of scrap steel on the other side and drill into it such that the bit never breaks through the backside because that is when they often snag and break. Note the ball mill will want to walk less then a regular end mill.

Amazon.com: Niagara Cutter CB230 Carbide End Mill, General Purpose, Uncoated (Bright), 2 Flutes, Ball End, 13/16" Cutting Length, 5/16" Cutting Diameter: Industrial & Scientific

acco1840 · Jun 22, 2011

I used 3/8 fine thread bolts in the contruction of my home made version of an Alaskan mill. I run a 25 inch solid nose Oregon bar on a Stihl 090. I used the factory hole at the bar tip and drilled another one at the powerhead end. I used a drill press on the slowest speed I can get, LOTS of constant pressure and a standard 3/8 High Speed Steel bit. I Used bar and chain Oil as a cutting lube, and the bit chewed through the bar in about 10 seconds. I have also drilled Stihl bars this way and havent had a problem. As for drilling through the sprocket tip, i have never tried it, but at the risk of destroying a $68 tip, I think I will stick with solid nose bars for milling. I cut Tasmanian hardwoods, and the solid nose bars havent given me any trouble.

BobL · Jun 22, 2011

acco1840 said:
As for drilling through the sprocket tip, i have never tried it, but at the risk of destroying a $68 tip, I think I will stick with solid nose bars for milling.

Oregon and GB solid nose bars are like butter compared to the middle of sprocket nose bars. But I have drilled about a half dozen sprocket nose bars (2 x 25" , 30" and 60" Stihls, and 42" and 60" GB) and not damaged one. In fact I have never heard of anyone damaging a sprocket bar nose by drilling it.

redoakneck · Jun 22, 2011

I have destroyed a spocket nose by putting too much pressure on it and smashing the bearings. $15 from baileys.

I bought 3 extra tips and a friend with a water jet drilled all 3 in the center of the bearing. Now I can just add a tip to any sprocket nose bar and Have that end ready for the mill.

60 bucks for a tip????

srcarr52 · Jun 22, 2011

redoakneck said:
I bought 3 extra tips and a friend with a water jet drilled all 3 in the center of the bearing. Now I can just add a tip to any sprocket nose bar and Have that end ready for the mill.

60 bucks for a tip????

Not everyone has a friend with a water jet. If I did, I would have plenty of stuff for him to do.

Probably $60 for a Stihl tip from the dealer.

acco1840 · Jun 25, 2011

Yep. $68 for a .404 sprocket tip from Stihl for a 25 inch 660 bar. And as I said, I havent drilled any sprocket tipped bars, so i wouldnt know.

sachsmo · Jun 25, 2011

This is coming from a guy that has screwed up a few times.

Get a carbide, center cutting end mill (or ball nose) Once you work harden a piece, even carbide will struggle to get through.

25 bucks for a good quality one, should last you a lifetime. (agree with the 5/16-18) Just go slow and careful on breakthrough, carbide will shatter like glass if abused.

aggiewoodbutchr · Jun 27, 2011

As others have said, a carbide end mill works best. However, I have been able to get the job done with a sharpened carbide tipped hammer drill bit in a drill press. Low rpms and lots of oil and pressure.

Any pointers for drilling (milling) holes in bars for modified alaskan mills?

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