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zz
 
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Default Machining question

hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz
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This is called snipe. On most machines the cutter head is above the wood
and supporting the end that is out away from the machine and even lifting up
slightly on it will help. What you are seeing is for the first 3-4 inches
the board is only being held down to the planer's surface by the roller in
front of the cutter head. Until the board travels through the machine far
enough to contact the back roller the board can tilt or lift up into the
cutter head causing more wood to be removed from the leading edge. The same
thing can happen at the trailing edge if the board is not supported when it
comes out of the machine.

Eric

"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz



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Leon
 
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"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??


It could be both. However almost all planers do this. You can help prevent
this by lifting the trailing edge as the leading edge first goes into the
planer. Additionally you can help prebent the trailing end from doing this
by lifting the leading end as the trailing end goes through the planer.


also is it beter to do the edges with a jointing machine or a bench
router and fence??


The jointer was specifically built to to this operation but only to
straighten or flatten one edge or surface of the board. Use a table saw to
make the opposite edge parallel to the edge straightened by the jointer.


  #4   Report Post  
George
 
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If you know the length of the area with the "snipe" then allow for it by
using a longer board and cutting off the "snipe".

"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz



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Edwin Pawlowski
 
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"zz" wrote in message

through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches

is it normal??
or is it a badly set up or low quality machine??


Yes, maybe, maybe.

Even the best of machines can give a little snipe at the front and rear
edges if it is no perfectly flat when going through the rollers. Be sure th
e machine is set up perfectly, feed the board and keep it supported, and
when it exits, keep it supported also.

While my planer is generally snipe free, I do not cut the final length utill
it is thicknessed as one little bungle on my part can cause the snipe. I
leave room to trim it off if needed.




I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it




also is it beter to do the edges with a jointing machine or a bench
router and fence??


Yes, you joint one edge, then run it through the table saw with the jointed
edge against the fence. If you don't have a jointer, you can make a sled
and do both edges on the table saw. Depending on what equipment is
availalbe, choose accordingly.








  #6   Report Post  
CW
 
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Some claim it's normal. Mine doesn't do it nor would I stand for it if it
did.

"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz



  #7   Report Post  
bridger
 
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I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it


here's a way to work around snipe when working with a particularly nice
or valuable piece of wood:
run through with it a second piece of wood, the same thickness as your
nice one, but a foot or so longer and made of something cheaper. if
your mahogany is wide, your second one might be two narrow ones, one on
either side, or it might be two short wide ones, one running through
immediately before the mahogany and one immediately after. and I mean
immediately- you'll be pushing one board through with the other.
what this does is move the snipe from your valuable board to a lesser,
sacrifical board.

  #8   Report Post  
John
 
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CW wrote:
Some claim it's normal. Mine doesn't do it nor would I stand for it if it
did.


Bingo. CW knows how to set up a machine.

Depending on the make of planer, you've got chipbreaker, infeed roller,
pressure bar, outfeed roller - all holding the board down. If you are
getting snipe on the leading end of a board, it's the infeed area
that's at fault. The only time you should get any snipe is if the
board is too heavy for the machine - then it's a simple matter of
supporting the end of the board until it's past the outfeed roller.

John Martin

  #9   Report Post  
zz
 
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On 6 Aug 2005 10:41:26 -0700, "bridger" wrote:



I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it


here's a way to work around snipe when working with a particularly nice
or valuable piece of wood:
run through with it a second piece of wood, the same thickness as your
nice one, but a foot or so longer and made of something cheaper. if
your mahogany is wide, your second one might be two narrow ones, one on
either side, or it might be two short wide ones, one running through
immediately before the mahogany and one immediately after. and I mean
immediately- you'll be pushing one board through with the other.
what this does is move the snipe from your valuable board to a lesser,
sacrifical board.

thanks
i especially like the idea of the sacrificial board
zz
  #10   Report Post  
 
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On planers with adjustable rollers You can lower the bottom outfeed rollers
and let the stock run on the bed. You will have to keep wax on the bed so
the stock will slide easy.
"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz





  #11   Report Post  
BillyBob
 
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"zz" wrote in message
news:42f4a532.31505923@news-server...

also is it beter to do the edges with a jointing machine or a bench
router and fence??


A jointer is a much more reliable method for the edges than a router. The
jointer will inherently be more accurate because you are referncing a longer
cast iron surface, compared to the very short (and possibly wood) router
fence.


Bob


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CW
 
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"BillyBob" wrote in message
k.net...

A jointer is a much more reliable method for the edges than a router.


No.


  #13   Report Post  
John
 
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bridger wrote:
I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it


here's a way to work around snipe when working with a particularly nice
or valuable piece of wood:
run through with it a second piece of wood, the same thickness as your
nice one, but a foot or so longer and made of something cheaper. if
your mahogany is wide, your second one might be two narrow ones, one on
either side, or it might be two short wide ones, one running through
immediately before the mahogany and one immediately after. and I mean
immediately- you'll be pushing one board through with the other.
what this does is move the snipe from your valuable board to a lesser,
sacrifical board.


Really don't see how this will have any effect at all on snipe. Unless
the boards are glued end to end.

I'll sometimes run boards end to end on my 12" Parks, or overlapping
side by side. The reason I do that, though, is that when taking
heavier cuts the boards will sometimes stop when they hit the front
edge of the chipbreaker. There's a handle on the front of the
chipbreaker to allow you to lift it slightly when that happens, but
it's easier to feed side by side to keep wood under the chipbreaker at
all times. Also makes use of the full width of the cutters and table.

Snipe at the start of a board, though, is caused by the chipbreaker or
infeed roller being set too high, or by the springs on those not being
heavy enough to keep the front of a heavy board from lifting. Running
boards end to end will have no effect on that.

John Martin

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Edwin Pawlowski
 
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"John" wrote in message

Really don't see how this will have any effect at all on snipe. Unless
the boards are glued end to end.


I don't know, but I was taught to do that and I've never had a bit of snipe
when I did. Could be a religious issue or something.


  #15   Report Post  
CW
 
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It's a force issue and, yes, it works.

"Edwin Pawlowski" wrote in message
...

"John" wrote in message

Really don't see how this will have any effect at all on snipe. Unless
the boards are glued end to end.


I don't know, but I was taught to do that and I've never had a bit of

snipe
when I did. Could be a religious issue or something.






  #16   Report Post  
 
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CW wrote:
It's a force issue and, yes, it works.

"Edwin Pawlowski" wrote in message
...

"John" wrote in message

Really don't see how this will have any effect at all on snipe. Unless
the boards are glued end to end.


I don't know, but I was taught to do that and I've never had a bit of

snipe
when I did. Could be a religious issue or something.




a major cause of snipe is the load on the board as it is fed into the
planer. You can minimise this by setting up an infeed and outfeed
roller stand to support the board.

Some of the small benchtop planers benefit from an additional table
such as an 8' piece of particle board shelving.

You can also reduce it somewhat by using a very fine initial cut.

the sacrificial board ia also an excellent option, it can be a small
piece of 1 x 2 nailed to the edge of your board.

  #18   Report Post  
Upscale
 
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"John" wrote in message

Right on all points, except that he was talking about a sacrificial
board not attached to the workpiece. Why that would work I can't
imagine.


I don't own a planer, but I'm guessing that a sacrificial board end to end
with the working piece would negate the sudden introduction of the to the
blades, eliminating most if not all of the snipe.


  #19   Report Post  
hylourgos
 
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BillyBob wrote:
"zz" wrote in message
news:42f4a532.31505923@news-server...

also is it beter to do the edges with a jointing machine or a bench
router and fence??


A jointer is a much more reliable method for the edges than a router. The
jointer will inherently be more accurate because you are referncing a longer
cast iron surface, compared to the very short (and possibly wood) router
fence.


Bob


Unless, of course, your router "fence" is a straightedge on top of the
workpiece rather than a true fence on the edge of the workpiece (for
example, see
http://www.rd.com/americanwoodworker...ble/page3.html).
In that case, your cut line will be as straight as your straightedge,
which is easy to make as long and accurate as any jointer bed.

In fact, one company even makes a fancy version:
http://www.thewoodshop.20m.com/jointabillit.htm

Since a router bit will cut the wood at *much* higher revolutions per
inch, the cut will be, correspondingly, much smoother.

Limitations a 1) set-up not as easy as a jointer that's ready to go,
2) careful prep to make sure your router is making an exact 90 deg. cut
(flat surface, calibrated straightedge, good machine, good bit, and
good control), and 3) you're limited to about a 2-3" cut. Even a 3" bit
on a router is stretching it, and it had better be a good quality bit.

If you can live with those limitations, then a router can theoretically
make a better cut, and it's infinitely more portable. Moreover, if
you're trying to joint a few items that are significantly longer than
your jointer's bed, then the router set-up is much easier than trying
to make longer infeed/outfeed beds for your jointer.

Been doing this on-site for years with good results,
H

....if you have a router table, it's even easier
(http://www.woodshopdemos.com/rtrplnr.htm)

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John
 
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Upscale wrote:
"John" wrote in message

Right on all points, except that he was talking about a sacrificial
board not attached to the workpiece. Why that would work I can't
imagine.


I don't own a planer, but I'm guessing that a sacrificial board end to end
with the working piece would negate the sudden introduction of the to the
blades, eliminating most if not all of the snipe.



Now I understand why I never get any snipe.

You see, I always leave my boards next to the planer for at least a
week before I mill them. With really difficult species, I'll sometimes
move them halfway across the shop first. I'll monitor things for a few
days and, as long as I don't hear any fighting or arguing, I'll move
them a bit closer. Then I'll say, in a quiet voice, "Mr. Planer, I'd
like you to meet Dalbergia nigra. He's visiting us from down south -
from Brazil, actually. Nigra, this is Mr. Parks." I wouldn't think of
introducing them suddenly.

Sudden introduction has nothing to to with it. A good planer that is
correctly set up and properly used will not give you any snipe.
Period.

John Martin



  #21   Report Post  
Tyke
 
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This is called "snipe" and is common to most planers. Good planers will
have a head locking device which can minimize the snipe, it just adds time
between passes to lock, unlock, adjust, lock again.

The new DeWalt planer claims "auto-lock".

My Delta 580 does a decent job at minimizing snipe when I lock the heads.

It can also help to lift the board slightly on entrance and exit.

If all else fails, ensure the boards are long enough so you can cut off the
snipe.

Dave Paine.


"zz" wrote in message
news:42f4a532.31505923@news-server...
hi
when putting a piece of 6x2 hrough a planing machine [thicknesser they
call it] i notice that at the start of the board after it pulled
through that there is a depression at the front of the board like the
knves really dug in for the first couple of inches then the rest is
pretty flat all the way along. They guy who was showing me how to use
it said thats normal [community access wood workshop].

is it normal??
or is it a badly set up or low quality machine??

I have some very high quality mahogany i want to machine and dont
really want to waste that leading edge if i can help it

also is it beter to do the edges with a jointing machine or a bench
router and fence??

as you can see i know very little so thanks for answering my very
basic question
zz



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