Planing timber

[wide74]

Hello all.

Right then, I'm having an issue planing timber this week. I'm making a door frame and door out of oak so the sections I'm working with are fairly hefty such as 75x300x2400 sawn for the casing. I've got a sedgwick MB4 planer/thicknesser which can cope just fine but what I'm finding is that sometimes I'm starting to get a bow in the timber even though I'm starting with the bow face down if that makes sense? Obviously that just means I end up planing more off the bits that I don't need to and washing timber. I was under the impression that pressure needed to be kept on the outfeed side of the block which I'm trying my best to do but I still can't get it boards flat. Is a power feed the solution do you think? If not how would you guys flatten boards of this size without a 4 sider etc. as I'm stuck with single phase where I am and have a somewhat limited budget. Smaller stuff for Windows are fine it's just big stuff.

Cheers.

[nickw]

Yes, keep the pressure on the outfeed table side, but not on any section of the timber that the blades have not yet touched. I.E. only on bits of the timber that have been made flat already.

[ja2_k]

I use a lot of oak and its a very temperamental timber. I find if your planer knives are slightly dull then you're oak will tend to ride over the blades causing bowing. I see your lengths are 2.4 m long I'm not sure if you're using roller stands on your outfeed,that will certainly help.
After straightening then going on to thicknesing yor oak can still bow if you take to much off,as the stresses are released from the timber.

[wide74]

Do you know what? I was thinking maybe the blades were dull as some of the timber is a bit 'mucky' but the finish seemed ok so I carried on. I'll swap the blades out and report back. Thanks guys.

[thatsnotafestool]

I've also got the MB. For those lengths of timber you definitely need some support on the outfeed and also ideally on the infeed. I don't like roller stands as they never properly support the timber evenly.

I copied the excellent idea that Jason (jfc) had and basically it's two pieces of timber hinged together. One bit (vertical) supports the end of the other bit which is horizontally mounted to the end of the outfeed table. A simple aluminium bracket with two slots in it slot over a couple of small bolts tapped into the end of the outfeed table.

Are you saying that you have some bow in your timber to start with? If that is the case then one trick that sometimes works is to plane a little off the top of the bow (imagine the timber is like a very flat arch - you plane the top of the arch a bit flat) then leave it overnight. Sometimes this releases the tension. I also plane with the bow uppermost (ie the timber is concave as it goes over the tables). I'll swap ends each time otherwise you can end up with the timber tapered.

[wide74]

Cheers,

After the earlier advice I removed the blades, gave them a hone and reset them to the outfeed. I have to say it is a lot better but without new blades I won't know if it's working to its full potential. I also think that jfc's idea with the tables sounds like a good one and I'll try that over my current set up of various balanced bits of wood on the tables either side. The timber I have is good stuff and is generally more cupped than bowed as it can be 2 foot wide plus. I do however always try to plane it concave side down but thatsnotafestool's method of turning after each pass I will try as I've noticed it can get a bit wedge shaped if it's a particularly bad piece. While I think on where does everyone get their blades from as my spare set from my old axminster planer don't fit? Also if anyone knows a saw doctor in the North Yorkshire area please let me know.

Thanks for your replies so far as well it's appreciated.

[thatsnotafestool]

You might like to take a look at the Barke Turnblade http://www.barke.de/web-content/eng/sysbarkeEN.html I've fitted them to my MB and they're brilliant. You can get them from Doug at Cutting Solutions.

The main advantage is that once you've set up the carrier to the right height, you need never waste anymore time setting planer blades.

[wide74]

Oh for God's sake! I was just after some new blades and now there is a shiny thing on offer and I love shiny things. Cheers thatsnotafestool!

[thatsnotafestool]

You'll thank me after you've got them

[Jonathan]

Have you checked that the infeed and outfeed are co plane?

Jonathan

[wide74]

Yeah they are bang on unlike the Chinese offerings from axminster I had before

[Tomyjoiner]

Ive also got s MB an anything over 4' i use my extension table on the outfeed. Bit of a fire door with legs on 1 end with m10 bolts on bottom of legs to alter height if beed be.clamped to the outfeed. you can knock somethin up in 15 mins an it'll change your world!!

[siafins]

Sharp blades are a good start but the tension in that oak is probably a lot to do with it. Most of my work is in oak, we machine oak boards for ledge and braced doors in European Oak, packs of nice flat boards, as soon as they go over the surfacer they bow, they all seem to straighten out if you thickness evenly both sides.

We have two surfacer's and outcome is the same on both most of the time.