I need some help machining fir

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Forum topic by TomB19 posted 05-25-2015 07:28 PM 1341 views 0 times favorited 7 replies Add to Favorites Watch
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52 posts in 3300 days

05-25-2015 07:28 PM

I’m sure this has been discussed, ad nauseum, but I haven’t found anything relevant in a brief search. A link or even search term help would be appreciated.

I have some fir lumber, both new and old. The old stuff is really old. Old growth. It’s like hardwood.

It has been drying in my shop for three years. My moisture meter isn’t particularly trustworthy but it shows in the 5% moisture range.

Most of it was recovered from a house I demolished some years back but it has been cleared of nails.

Even in areas where the grain is perfectly straight, it chips out. I’ve tried both the really old stuff and some stuff that has been drying a couple of years old.

I’ve been trying to mill a 1×3 with a bull nose. I don’t have a bull nose bit so I’ve been using a 3/8” roundover. It has been chipping like crazy in areas where the grain is being slightly crossed (just a few degrees). Climb cutting helps in these areas but with the grain not being perfectly straight, I would have to climb cut/straight cut in tiny increments. It would take forever.

I’ve seen plenty of nicely milled fir, so I know it can be done.

I’ve been contemplating using a humidifier to bring the moisture level up closer to 10%.

Thank you in advance for any help! :)

7 replies so far

View exelectrician's profile


2339 posts in 3760 days

#1 posted 05-25-2015 07:46 PM

I have done a lot of fir and what I have found is dull tools will chip and tearout for sure. I keep a set of razor sharp bits reserved for only fir, that way I usually get great results. One more thing, feed slowly and take incremental cuts with the last cut being just a few thousandths for that glass smooth finish, with almost no sanding needed.

-- Love thy neighbour as thyself

View TomB19's profile


52 posts in 3300 days

#2 posted 05-25-2015 08:38 PM

One of the pieces of info I didn’t include is that I am using a Yyonico router bit. They’re not the best, to be honest, but I’ve had reasonable service out of most of them with a hand full of duds that should never have been shipped.

I’ll try implementing your advice with a fresh Whiteside bit and see what happens.

Thank you, former electrician. :)

View Ghidrah's profile


667 posts in 2555 days

#3 posted 05-25-2015 09:28 PM

Fir is brittle, use sharp bits, lite cuts and follow the grain. Even VG Fir will chip, you may even need to employ climb cuts to minimize tear out.

-- I meant to do that!

View Ted's profile


2877 posts in 3543 days

#4 posted 05-25-2015 10:13 PM

If you’re using a hand router, try going in reverse direction—from right to left. Just be sure to go slow and hang on tight so it doesn’t run away from you. I’ve had good success with otherwise chip-prone woods. Taking it in a couple of passes is still probably best.

-- You can collect dust or you can make dust. I choose to make it.

View BurlyBob's profile


9510 posts in 3598 days

#5 posted 05-25-2015 10:14 PM

I think your on the right track with Whiteside bits. Carbide has really good prices for them. I bought several awhile back and have no complaints about the bits or the service there.

View gfadvm's profile


14940 posts in 4022 days

#6 posted 05-26-2015 12:19 AM

I have milled a lot of old growth Doug Fir salvaged from my dad’s 60 year old barn and have had the chip out/ slivering problems. A sharp/quality bit helps but routing with numerous shallow passes is a better option (especially with that 3/8” roundover which removes a lot of wood with a full depth pass.) A little tedious but less so than having to make a new piece after your router shredded the original.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View TomB19's profile


52 posts in 3300 days

#7 posted 06-01-2015 04:45 AM

Thank you gentlemen. The help is much appreciated.

I’m having much better results with a Whiteside bit and shallow passes.

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