Working interlocking grain

[Jelly]

I'm having a bit of a struggle planing the legs for my current project, it's proving impossible to take thick shavings without big fragmented chips forming* and taking thin shavings with the jack and then the coffin smoother held at a 40-60 degree angle to the direction of planing is giving lovely, glass smooth results on 90+% of the surface but some of the grain seems intent on tearing out no matter what.

Frankly, I know I could just sand it smooth, but it's a horrific rigmarole i'd rather avoid.

It's in purpleheart, which is a bit of a sod anyway... so I'm having to keep the irons absolutely razor sharp, for all the good it does.

Any suggestions greatfully recieved (I have a spare bailey-type No. 4 plane available if it's worth trying a different blade angle).

*t's not forming nice shavings, at anything less than the finest cut it forms curls formed of small straight sections of fractured fibres joined up... almost resembling type 2 chip formation, every so often flakes of wood will come away attached to a shaving, I've noticed slight internal fractures elsewhere in the material, so perhaps that's inevitable.

 

[Argus]

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Scrapers?

They can be very hard work if you have a lot of wood to cover, so if planes-only is your tool-of-choice and if it’s tear-out grain, then it may be down to the attack angle of your blade.

I sometimes encounter interlocking and tearing grain in European Oak, which I use a lot.

Sometimes you can spot the way the grain lays and attack from the other direction so that you are always planing down the grain, though if it rises and falls along the board this doesn’t work too well.

Stanley planes are bedded somewhere around 45 degrees, what is called Common Pitch - fine for softwood and compliant grain but they tend to be challenged by harder woods.

There are those who favour bevel up variations, though I have found that planes with blades bedded at Half Pitch – 60 degrees - coupled with a very, very sharp blade and a tight mouth are most effective. With bevel-ups at a bed of 20 degrees you are sharpening at 35 degrees or more to achieve an effective cutting angle. Additionally they are expensive to buy.

You may consider finding a seller of Chinese wooden “Hong Kong” style planes that are bedded at half pitch - Mujingfang are the makers. Don’t let the origin put you off – although they are relatively inexpensive, in my opinion they are superb for ornery grains of all types once they are fettled and may deal with your problem. With your wood it would certainly be the first plane I would reach for....

A more drastic approach would be to put a 15 degree back bevel on the iron and move the frog as far forward as it will go....... or to wedge the back of the frog to get the blade angle up to about 60 degrees....

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[Jelly]

Putting a backbevel on the iron sounds ok... I basically never use that plane these days, so if i set it up as a high angle "awkward woods" plane it's a net gain, edge might be a bit weak though...

 

[Jelly]

Bam! Worked a treat, there's some grain that's just too awkward to be sorted with a plane, but a very fine sandpaper and some thick shellac should see an more than acceptable finish.

I have no idea what back bevel I put on the iron, based on where my hands were, its around 15-20 degrees; anyway, it works well, which is all that matters; still don't like metal planes though and not just because the standard totes are too small for my hands.

 

[Argus]

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Well, there you go.

If it's use is infrequent, why not get a spare No 4 blade on eBay and keep one just for dodgy grain.....

If you really prefer wooden planes, lash out on one of the Hong-Kong jobs - I swear by 'em.

All best
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[Derek Cohen (Perth Oz)]

A slicing action tends to make it easier for the plane to cut. However this could also have led to the tear out experienced here.

On surfaces that are inclined to tear out high cutting angles aid in taming tear out (hence the success with the scraper). On such timber surfaces one should avoid holding the plane at an angle to the grain. Instead plane directly with the grain. When you skew the plane you lower the angle of attack. You really want to preserve the highest angle you can. Keeping the plane straight preserves the cutting angle.

Regards from Perth

Derek

 

[mickthetree]

I do believe Matthew over at workshop heaven has started selling the Mujingfang Planes