Tear-out in Oak boards

[John15]

I'm currently making a 1500 x 900mm oak dining table for my own use. I have completed the legs and rails satisfactorily but have run into trouble with the four no. boards for the top. The boards were bought sawn 27mm thick with the intention to plane to around 20mm. I first reduced the thickness to 22mm on my p/t but there was a lot of tear-out despite only taking off around 0.5mm with each pass. To attempt final finishing I have used a smoother and a block plane, and a scraper but have been unable to illuminate the tear-out. My question is should I adopt a different method or is it extremely difficult to produce a good finish to certain cuts of oak. The wood is not quarter sawn as I dislike maddulery (wrong spelling?) rays - I think they look messy. I'm tempted to bite the bullet and buy in replacement material but what cut should I be looking for?

John

 

[Paul Chapman]

For an oak table top, I would use a scraper plane. I successfully used one on this oak table top



Cheers :wink:

Paul

 

[undergroundhunter]

Super sharp plane with a close set cap iron on a light cut or a No 80 scraper (sharpened up) works for me, for localized tear out use a card scraper. Also make sure you are planing on the correct direction. A photo of the tear out may help. Shouldn't make a difference weather its quarter swan or not depends on the look you are going for. I wouldn't scrap it, I would guess its not the wood its either a tool or a technique issue.

HTH
Matt

 

[blackrodd]

Sorry to hear you're problem.
Does any workshops near you have a drum or sanding thicknesser, or is the breakout too deep?
Regards Rodders

 

[John15]

Thanks for the comments guys. The depth of the tear-out is about 1mm. What's making things more difficult is using a scraper in localized areas is reducing the thickness, then having to plane the rest of the board to the reduced thickness resulting in more tear-out. I'm chasing my tail and the boards are getting thinner and thinner.

Maybe I'm just unlucky with the table top boards. The finish on the rails and legs is perfect. Could it be the difference between kiln and air dried timber? It was all bought from the same supplier.

John

 

[custard]

It's not the wood John, that's a fact, the problem's elsewhere.

Firstly, when you encounter tear out, from a hand plane or a machine, then stop what you're doing and figure it out. Sounds like you're now in the last chance saloon but I guarantee there's an explanation and a solution, where as if you just buy replacement timber you'll have the problem all over again.

You said the legs and apron worked out well. Was this from the thicknesser, the hand plane, or both? And why were those components okay when the top, from the same source, isn't? First place I'd look is the sharpness of your tools. As a rule of thumb I'd be expecting to sharpen a hand plane after 15 minutes of constant planing. And a machine planer with normal HSS blades will be past its best after an hour of constant use. If I'm working with furniture quality timbers then I change my machine planer blades every time I empty the dust extractor bag.

Next point, never use a scraper locally. You think you've fixed the problem but as soon as the finish hits the surface those localised scraped depressions will become horribly obvious.

It's time to start experimenting on scrap as you can't remove any more wood until you're sure you've got a solution.

If your blades are sharp, you're planing downhill, and you're still getting tear out then think about hand planing at 45 degrees to the grain and finishing with an all over application of the scraper.

Good luck!

 

[Random Orbital Bob]

took the words right out my mouth. On the P/T I would also ensure that your blades are freshly sharpened. Last time I used sawn oak for a cabinet and some doors I ended up going to down to no more than about 1/10th mm in each pass. Also "planing down hill" as Custard puts it is crucial on really hard timber like Oak. Ensure the grain orientation is correct before you feed it. I mark mine with a tonking great pencil arrow.

But for me, the scraping and any hand planing should be a finessing process after you're true and thick (nicest possible way). That's down to the P/T steps and from my own experience that's where the problems lie. Sharp blades, thinner passes, correct grain direction.

 

[John15]

Thanks Custard and Bob. Some sound analysis of my problem. I have plenty of oak scraps so will try out your suggestions.

John

 

[PAC1]

I also think it is down to the sharpness of the blades on your P/T. I have a terse block so would use a new set for a task like this. If the tearout is local I sometimes get a water spray bottle and just damp the surface in the effected area it softens the fibres just a little and makes them less brittle. Reduce the thickness in small steps 0.25mm or less.if you can do 0.1mm at a time so much the better.

 

[John15]

Thanks for your helpful suggestions PAC. You are spot on and as others have said - planer and hand plane blades were a bit dull I'm embarrassed to say and I'm afraid that with all my attempts to get the finish right the boards are now only 19mm in places so too thin for my table top - but not wasted, they'll come in use for a future project . So, today I've bought some new stuff from a local sawmill (Eynsham Timber near Witney). The owner had to dig around for what I wanted so fingers crossed. I've just planed one piece and it's good. There are one or two old knots which I like for effect and start a new post for the best way to treat them.

John

 

[AndyT]

In my opinion 19 mm oak is plenty thick enough for a table top, but it's down to your own taste and judgement of course.
There is a compromise often found on old tables where you make a frame of similar timber and fix it under the top so that the edges are twice as thick as the rest of the top, which you cannot see.
This has the extra advantage of being economical with materials and making a table which is not too heavy to move. I think it was called 'bodying up'.

 

[John15]

Many thanks Andy for your comments but 19mm or maybe slightly less is thinner than I wanted and as I'll be sitting at it every day it would niggle me.

As I've mentioned above this new batch I've bought today looks good. I've planed a second board this afternoon and I'm pleased with it. They have an interesting grain with some very attractive knots with short cracks radiating from them. I was wondering how best to treat the knots. For a finish to the boards I intend to apply two coats of Liberon Finishing Oil followed by Black Bison Wax. Would this stabilize the knots or do I need to treat them differently?

John

 

[Racers]

I filled the knots in my pippy oak boards with epoxy mixed with ground instant coffee to colour it.

Pete

 

[John15]

That sounds a good solution Pete - were you able to get a good finish on the epoxy? It will hold and seal the fragile part of the knots. In a way part of me is glad I had to get replacement timber - it has a more interesting grain and with my now sharp planer blades I'm full of excitement and optimism again!!

John

 

[Racers]

Yep, it consolidated things a treat and finished very well if you leave it to fully harden, overnight is best. You night need a couple of goes it the cracks are deep it settles in.
I used the Wilco's cheap epoxy Araldite went off as I was mixing it.

Pete

 

[John15]

Thanks Pete

John

 

[John15]

I've had better luck with the replacement table-top boards. The sharpened planer blades produced a good finish with no tear-out. Also taking thinner cuts helped. Thanks again for the good advice.

The glue-up has gone well - doing one board at a time helped. I'll post another pic when the finishing is complete.

John

 

[James C]

Looks like a very organised shop! Having zoomed in on your photo the wood looks like it could be quite interesting.

Looking forward to see how this turns out.