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Thread: Pitting when planing purpleheart

  1. #1

    Pitting when planing purpleheart

    I ran some Purpleheart through my planner with brand new cutters and it created terrible pits. I tried really light passes, I was careful with grain direction, Iím really not sure what to do differently. Any advice?

  2. #2
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    Some material is tearout prone despite our best efforts. Certainly the cost (and waste / reassignment factor) of my more expensive material is what drove me to insert heads and I never looked back. Prior to moving to helical heads I had read and tried almost every cure; spritzing with water, super light cuts, running material through on a slant (to make your knives perform a shearing cut) and so forth. I was able to get through some things by switching to a hand plane with a steep (50 degree or so) angle. This was fine for small parts but, larger pieces tuckered me out .

    A change to or replacement of a machine has to be a qualified expense for me. I made the switch nearly 20 years ago and so have easily recouped my layout many times. The idea of doing this needs to be looked at mathematically. If it makes sense long term I would consider it. If exotics or highly figured material is a now and then thing, I would just grab a hand plane and work through it.
    Last edited by glenn bradley; 10-17-2020 at 7:17 PM.
    "The Danish government believes that if we train 5,000 designers, and produce
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  3. #3
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    Jason, Glenn’s advice is good. This is the value of hand planes. They are capable of working tearout-prone timber best of all. However, this is not a technique for one not versed in these tools. An alternative is a scraper for finishing or removing small sections of tearout. Otherwise you are left with a wide drum sander.

    Regards from Perth

    Derek
    Last edited by Derek Cohen; 10-18-2020 at 6:41 AM.

  4. #4
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    I would clean up the planer wipe up any dust resharpen knives and throw the purple wood in the scrap bin.
    Hate that stuff.
    Aj

  5. #5
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    Wipe down the wood with a wet cloth before planing, and angle it across the bed as much as possible to make more of a shear cut. Planing purple heart is like planing a rock. Never buy a board with rowed grain, just flat sawn. I did a small jewelry box for my daughter when she was young in the early 80s. I still have half a board. Swore I'd never run that stuff through a planer again.

  6. #6
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    Maybe just a bad part of the tree, I run Purpleheart through my A3-31 all the time and it comes out very nice.

  7. #7
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    Wood like that is one of the reasons why I got a drum sander. Even with my helical head planner on occasion I still get problem wood. It's a slow process but a course grit on the drum sander will remove it with enough passes. But once I pick a wood I want for a project I tend to be stubborn and not give up on it. I'm sure if you figure in the extra time and costs it would most likely make more sense to just move on.

  8. #8
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    Some species like this can tend to be brittle and splintery. (and those splinters are not fun when they are inside your flesh, too) I have not worked with a huge amount of purpleheart but while most of it milled out cleanly, I do remember "that one board" that just wouldn't cooperate. Sometimes the grain in a particular board is just whacky and chunks out accordingly. Hand planes and a drum sander can help to get a decent surface on "those" boards as has been noted.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  9. #9
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    Difficult wood

    Quote Originally Posted by Jason Carlin View Post
    I ran some Purpleheart through my planner with brand new cutters and it created terrible pits. I tried really light passes, I was careful with grain direction, Iím really not sure what to do differently. Any advice?
    As most of "exotic" hard wood it is a very difficult wood to work. It is one of hardwood species from Brazil as well other similar woods (like ipe, peroba rosa, angelin and massaranduba) it is not an easy wood to work. I recently made a great English workbench from massaranduba and one particular piece is with terrible pits also.

    There is a reason most those hard woods are locally used for constructions instead of fine furniture...

    My experience is most of the times it is not easy but sometimes I get a piece that respond reasonably to milling either by machine or manually.

    Sometimes I envy the wood species from temperate regions - they look way more workable, in general.

    My wishes you find a workable piece.
    All the best.

    Osvaldo.

  10. #10
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    I'd be curious if anyone has ever came across a wood species more likely to inflict splinters than purpleheart? I have not, and I think that grain characteristic is why it's hard to plane. It does sand pretty well.

  11. #11
    I used Purple Heart to trim out the panels on the shop doors. It looked pretty, but it didnít cut so much as shatter. I had to cut deeply to get it out of my middle finger. Ironic. I stick to the domestics I know now.

  12. #12
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    For about the same money as it would have cost to retrofit my straight knife J/P with a helical head I bought a used dual drum sander. It has no trouble dealing with tearout and is the best tool around for sanding shop sawn veneer dead flat and smooth. As the OP has shown, helical heads don't necessarily eliminate tearout. The good news is there are alternatives that do.

    John

  13. #13
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    Quote Originally Posted by Steve Rozmiarek View Post
    I'd be curious if anyone has ever came across a wood species more likely to inflict splinters than purpleheart? I have not, and I think that grain characteristic is why it's hard to plane. It does sand pretty well.
    Wenge comes to mind.... but any species that can be "brittle" is a bigger risk for this, IMHO.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  14. #14
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    Douglas fir is has a particular way that makes splinters fester at least for me. Itís so hard to see them because they are the same color of the my flesh. After a couple days the infection helps to get them out.
    Aj

  15. #15
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    Purpleheart is one of my favorite woods. Yes it gives me splinters if I am not careful but I have not had trouble working it. It may be that my source provides only good stock, or I have been lucky. If you want to dispose of some, send it my way.

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