Thickness Planer Questions - slight digs at beginning and end of wood

[workingwood]

I have had a thickness planer for years it is a Delata 12" planer. My problem I have been trying to figure out how to fix is when I put the wood in it cuts down a little more on the entry and exit parts of the wood which causes me to take a cabinet scraper to the wood to smooth that transition out. Has anyone had this problem before and how can I fix this.

As a note I have made sure the beds that came with it are level all the way through the planer, I have replaced the heads, tried to take even lighter cuts, used in-feed and out-feed tables with no different result. the only thing that has seemed to produce the results I want has been to proceed the piece of wood I want to plan with another piece of wood and then push it through with another that seems to take care of the problem. I am just tired of doing that and I am hoping there is a fix somewhere.

 

[ScottM]

It is called snipe. You can google solution but basically you need to adjust the input and output feed tables as well as insuring your wood is proper supported.

http://www.highlandwoodworking.com/understandingsnipe.aspx

 

[workingwood]

Scott thanks for the correction on what it is called I could not remember the name of that to save my life. I thought of snipe but I hunt those fast flying things so I thought I might be getting a hunting term and a wood working term confused. thank you for the link I will have to see what other adjustments I can make to correct this.

 

[Jeremy Scuteri]

...the only thing that has seemed to produce the results I want has been to proceed the piece of wood I want to plan with another piece of wood and then push it through with another that seems to take care of the problem.

The fact that this remedies the problem indicates that infeed/outfeed support is not the main cause of the snipe. If the board is long and unsupported it can push up into the cutterhead (through leverage) and the same thing can happen if your infeed/outfeed tables are slanted downward (this would automatically angle the board upward until the 2nd feed roller pushed the board down to the planer bed). If either of these were the cause, then feeding one board right after another wouldn't change anything. Another test to eliminate unsupported boards is to see if you get snipe on shorter boards that are well supported. You can eliminate the infeed/outfeed tables as the main cause by purposely setting them slightly angled upward and see if you still get snipe. I had a dewalt 12.5" planer that came with the infeed/outfeed supports angled slightly upward from the factory and I didn't have any noticeable snipe on it.

Contrary to what the highland woodworking article states, another cause of snipe is that the cutterhead does move/deflect a very small amount when there is a force exerted on the infeed/outfeed rollers (from the board). As the board enters the planer, it first hits the infeed roller which will raise the cutterhead assembly a tiny amount, then it hits the cutterhead which starts cutting at a given thickness. Then the board hits the outfeed roller and raises the cutterhead a little more and the entire "middle section" of the board is planed at a nice consistent thickness (slightly greater than the first few inches of the board) until the trailing end of the board is no longer pressing against the infeed roller which causes the planer to fall slightly causing it to cut a tiny bit deeper just as it did on the leading edge.

Although there are sources saying that the cutterhead does not move, this is the only mechanism for snipe that explains why feeding one board right after another eliminates snipe on all boards except for the very 1st board and very last board. All the "middle boards" had both feed rollers engaged and therefore kept the cutterhead at the same height.

Another piece of evidence that supports that the cutterhead does in fact move slightly when a force is exerted on the feed rollers is that many people are able to reduce snipe by REDUCING the spring tension on the feed rollers. If the cutterhead truly didn't move, and all snipe was caused by the board lifting, then snipe should be improved by INCREASING the feed roller spring tension not reducing it. A higher spring tension should hold the board down more firmly to the planer table. Reducing the feed roller spring tension reduces the upward force exerted when a board runs through the planer, less upward force leads to less deflection of the cutterhead. I have improved snipe on my grizzly 15" 4 post planer by reducing the spring tension (a recommendation from some users on this forum).

http://woodgears.ca/jointer/planer_snipe.html

Do you have a locking mechanism on your planer? Do you use it?

Sorry for the long rant. I have spent too many hours thinking about and reading about snipe when I needed to adjust my brand new Grizzly 15" planer which had pretty bad snipe when I first got it. It was an upgrade from my Dewalt 12.5" planer that didn't have any snipe issues...

Jeremy

 

[merrill77]

After making all the usual adjustments (adjusting lower table rollers and the infeed/outfeed tables), I was finally able to remove virtually all snipe from my planer by raising the infeed and outfeed rollers so that they are just low enough to keep the boards moving through. I'm not sure if this is what Jeremy refers to - as I'm not actually changing the spring tension (at least not directly).

The downside of this approach is that the rollers are not down far enough to feed rough stock...so I have to reverse the adjustment when I'm planing rough stock and then re-adjust again when all the stock has been surfaced.

 

[Jeremy Scuteri]

After making all the usual adjustments (adjusting lower table rollers and the infeed/outfeed tables), I was finally able to remove virtually all snipe from my planer by raising the infeed and outfeed rollers so that they are just low enough to keep the boards moving through. I'm not sure if this is what Jeremy refers to - as I'm not actually changing the spring tension (at least not directly).

The downside of this approach is that the rollers are not down far enough to feed rough stock...so I have to reverse the adjustment when I'm planing rough stock and then re-adjust again when all the stock has been surfaced.

As you pointed out, you aren't changing the spring tension, but you are reducing the amount of upward force exerted on the feed roller when feeding a board through which will have the same effect as far as "cutterhead deflection" snipe is concerned. I wonder if you would be able to find a setting that gave good results on rough stock and surfaced stock if you were to adjust the spring tension (reduce the spring tension and lower the rollers). This may allow the rollers to maintain contact with rough stock without deflecting the cutterhead excessively.

Jeremy

 

[ehpoole]

After making all the usual adjustments (adjusting lower table rollers and the infeed/outfeed tables), I was finally able to remove virtually all snipe from my planer by raising the infeed and outfeed rollers so that they are just low enough to keep the boards moving through. I'm not sure if this is what Jeremy refers to - as I'm not actually changing the spring tension (at least not directly).

The downside of this approach is that the rollers are not down far enough to feed rough stock...so I have to reverse the adjustment when I'm planing rough stock and then re-adjust again when all the stock has been surfaced.

Just be careful with this setup. With so little feed roller pressure/contact there is an elevated risk of a kickback event launching a board backwards out of the infeed side. Although one should always stand to the side when feeding a board into the infeed side, rather than behind, it becomes more critical to follow this safety advice with this sort of modification.

Otherwise, I wish you all the best.

 

[ehpoole]

It is called snipe. You can google solution but basically you need to adjust the input and output feed tables as well as insuring your wood is proper supported.

http://www.highlandwoodworking.com/understandingsnipe.aspx

The most common solutions for reducing snipe are 1) Lift up on each end of the board as it first makes contact with the cutterhead AND as it loses contact with the cutterhead OR 2) Adjust the infeed and outfeed tables so that the outside (leeding or trailing) edge is a bit higher than the planer's bed, which as a similar effect to lifting the board ends. The third solution practiced by some is to always cut your boards a few inches over length, thickness plane them, then cut them to final length -- this works because the length of the snipe will always be equal to the distance between the center points of your cutterhead knives and the infeed/outfeed roller, so the distances never change.

Most thickness planers have at least some snipe and the amount varies greatly amongst both different models and different types of wood. For example, my DW735 occasionally has about 0.001" of snipe on some boards and none with others -- and I don't even have the optional infeed/outfeed tables installed. But then this model was designed specifically to reduce the typical causes of snipe (and you pay a premium for it).

With models that have very little snipe (such as the 0.001" of my DW735) it is often not worth worrying about because a few passes with 120grit during sanding (or a quick session with a scraper) and all evidence of such is gone. It is more problematic for models with much deeper snipe. It is also worth remembering that, in general, the thickness planer is not meant to be a finish-perfect surface, so some limited sanding or scraping is generally considered normal procedure any how.

 

[red]

I have always just planed my lumber a little longer than needed and then cut it to length.

Red

 

[Charles Lent]

I had this problem for years with an early Delta "lunchbox" planer (don't remember the model #). I could minimize the snipe, but could never eliminate it. I adjusted, and re-adjusted, used scrap wood ahead of and behind my work, raised the infeed and outfeed tables, and even tried replacing the feed tables with a length of melamine covered shelving running completely through the planer. There was a design flaw in the planer. The head could move as the roller pressure changed, causing the knives to cut differently as the feed rollers contacted and dropped off of the ends of the boards. Nothing that I tried completely solved the snipe problem.

Then I did something that solved my snipe problem forever. I gave the Delta planer away and bought a DeWalt 735. With the DeWalt there is still snipe, but it's almost non-existant. If you look close at the board surface you can see a faint narrow line. A couple of swipes with a block sander and 150 grit paper eliminates the line. The 735 has four lead screw posts to hold the head parallel to the base. The old Delta only had 2 lead screw posts.

Charley

 

[merrill77]

Just be careful with this setup. With so little feed roller pressure/contact there is an elevated risk of a kickback event launching a board backwards out of the infeed side.

My planer is the typical 15" planer design, which includes anti-kickback fingers (pawls?). I can assure you that they work as intended. I have tried on several occasions (with the planer off) to pull wood back out and it doesn't budge....and then I remembered the anti-kickback fingers.

But your advice should be noted by those who do not have such safety devices on their planers. Do most benchtop planers have these?

 

[Pop Golden]

This is my observation: I had a Powermatic 15 inch plane with straight knives. Sold it and bought a Powermatic 15 inch with Byrd-Shelix knives. The snipe is far less with the staggered knives of the Byrd type head. Also considering the mass and weight of this plane I find it very hard to believe the cutter head assembly is moving anywhere. I may be wrong but I see my input & output table as the cause of what little snipe I have. I've just been too lazy to fix it.

A couple of things about the DeWalt DW735 thickness plane. Back when this plane was in the development stage a protype was brought to my woodworking club. The question was, give us your opinion and ideas. A few months later DeWalt came back. This time they had a stack of around a dozen boards with snipe. The question was, what is an acceptable amount of snipe. After a debate the club concluded that if we could see a snipe, but not feel it it was acceptable. That meaning a few strokes of sandpaper would make it go away. This is why that plane has bed locks.

Bill "Pop" Golden

 

[Jeremy Scuteri]

This is my observation: I had a Powermatic 15 inch plane with straight knives. Sold it and bought a Powermatic 15 inch with Byrd-Shelix knives. The snipe is far less with the staggered knives of the Byrd type head. Also considering the mass and weight of this plane I find it very hard to believe the cutter head assembly is moving anywhere. I may be wrong but I see my input & output table as the cause of what little snipe I have. I've just been too lazy to fix it.

A couple of things about the DeWalt DW735 thickness plane. Back when this plane was in the development stage a protype was brought to my woodworking club. The question was, give us your opinion and ideas. A few months later DeWalt came back. This time they had a stack of around a dozen boards with snipe. The question was, what is an acceptable amount of snipe. After a debate the club concluded that if we could see a snipe, but not feel it it was acceptable. That meaning a few strokes of sandpaper would make it go away. This is why that plane has bed locks.

Bill "Pop" Golden

I have a Grizzly 15" 4-post planer with a spiral cutterhead (very similar to the powermatic 15" planer) and I have experienced snipe that seems to indicate the cutterhead was moving [pulling up on boards as they enter/exit the planer did not help, adjusting the infeed/outfeed dead level or angled slightly upward at the outer edges didn't help]. The only things that did help were running one board right after another which helped on all boards except the 1st and last and finally reducing the spring tension on the infeed/outfeed rollers really helped a lot. I would agree with your skepticism about the cutterhead moving if I hadn't gone through this very frustrating experience. If pulling up on the boards as they enter/exit the planer doesn't help, then you can adjust the infeed/outfeed tables as much as you want and it won't help either since it will apply the same failing remedy (of course, there are times when the board tipping is causing snipe and adjusting the tables can help in those cases). When you have time, you should see if pulling up on the boards reduces the snipe and if it doesn't try adjusting the spring tension (it is easy to do with 4 easily accessible bolts on top of the planer)

Since snipe varies quite a bit from planer to planer, it is hard to say if the real cause in reduction of snipe is the new planer or the spiral cutterhead. I don't see any physical reason that a spiral head would have less snipe than straight knives. My guess is that it was something in the new planer (infeed/outfeed tables aligned better, less cutterhead deflection, less spring tension, etc)

Jeremy

 

[Jeff]

I have always just planed my lumber a little longer than needed and then cut it to length.

Red

+1. If your setup is good to go why make life complicated by playing with it in a frustrating effort to eliminate planer snipe? Simply add about 3" to each end to account for the snipe and then cut it to length below the snipe.

For example: You buy a 4/4 board 8.5' x 8" x 1 = 5.66 bf. You pay $6/bf so it's $33.96. Then you run it through your planer snipe and all and trim 3" off of each end so you end up with one board that's 8' x 8" x 1 = 5.33 bf. Your net loss is $1.98 with no headaches and playing around with the setup!

 

[zapdafish]

I solved my snipe problems by waxing the tables. The feed rollers were having to really work hard to move the wood through and I had track marks along the top surface as well from the lead roller.

 

[Jeremy Scuteri]

+1. If your setup is good to go why make life complicated by playing with it in a frustrating effort to eliminate planer snipe? Simply add about 3" to each end to account for the snipe and then cut it to length below the snipe.

For example: You buy a 4/4 board 8.5' x 8" x 1 = 5.66 bf. You pay $6/bf so it's $33.96. Then you run it through your planer snipe and all and trim 3" off of each end so you end up with one board that's 8' x 8" x 1 = 5.33 bf. Your net loss is $1.98 with no headaches and playing around with the setup!

The issue with simply eliminating 3" from each end is that it must be done to every board. In your example where 6" is lost on a 8.5' long board, it isn't very significant. I don't know about everyone else, but I try and cut my pieces to rough length before running them over the jointer then the planer. This allows me to get the maximum thickness from rough cut lumber. I would not want to face joint an 8.5' long board (boards should face jointed before going through the planer) if I didn't have to. So, if you like to rough cut to length before making everything square on 4 sides (which makes the process much easier and results in thicker boards) then this 3" on the beginning and end of every board suddenly becomes much more significant. Assume you have several 15" long boards that are needed, if you have to cut each one to 21" to allow for 6" to be cut off that is roughly 30% being wasted. In this case, I find it worth the effort to reduce the amount of snipe from my planer to a tolerable level. Even in your case you are adding $2 to the cost of every 8.5' long board that you process over the lifetime of the planer. If you do a lot of projects, that will add up over time.

 

[Pop Golden]

[QUOTE=RonJr Since snipe varies quite a bit from planer to planer, it is hard to say if the real cause in reduction of snipe is the new planer or the spiral cutterhead. I don't see any physical reason that a spiral head would have less snipe than straight knives. My guess is that it was something in the new planer (infeed/outfeed tables aligned better, less cutterhead deflection, less spring tension, etc)

Ron you're not thinking the cutter head difference through. With straight blades you have 3 or 4 knives striking the wood at one at a time. With the staggered cutters on a Byrd type head you have 100 or so cutters to engaged with the wood one at a time. This means you have almost continuous contact by the insert cutters. This is why the Byrd head is much quieter and has a somewhat smoother finish. The single blades bounce on impact. Remember, a snipe is a single line. This is why we pay that extra money for that type of cutter head.

Bill "Pop" Golden

 

[Jeremy Scuteri]

Since snipe varies quite a bit from planer to planer, it is hard to say if the real cause in reduction of snipe is the new planer or the spiral cutterhead. I don't see any physical reason that a spiral head would have less snipe than straight knives. My guess is that it was something in the new planer (infeed/outfeed tables aligned better, less cutterhead deflection, less spring tension, etc)

Ron you're not thinking the cutter head difference through. With straight blades you have 3 or 4 knives striking the wood at one at a time. With the staggered cutters on a Byrd type head you have 100 or so cutters to engaged with the wood one at a time. This means you have almost continuous contact by the insert cutters. This is why the Byrd head is much quieter and has a somewhat smoother finish. The single blades bounce on impact. Remember, a snipe is a single line. This is why we pay that extra money for that type of cutter head.

Bill "Pop" Golden

With straight blades, you only have 3 or 4 blades total in the cutterhead and only 1 of them is striking the wood at any given time, the other ones would be on the sides and top of the cutterhead and are only hitting air until they rotate around and hit the wood. Granted when the blade hits the wood, it is touching the wood across it's entire width. The spiral cutterhead doesn't cut across the entire width with a single blade which helps with noise and maybe tearout. The "single line" that you are referring to just marks where the snipe starts/ends. You will see this "single line" about 3" or so from the end of the board. The thickness of this 3" section is less than the rest of the board, so I would argue that this entire 3" section is snipe, not just the line that marks the boundary. If the straight blades were bouncing when they hit the wood and this was in fact the difference/cause of the snipe, why is it only occurring at the last 3" of the board since this bouncing effect should be occuring over the entire length of the board? What is different there than the rest of the board? As another user stated earlier, this ~3" distance is exactly the same distance that exists between the center of the feed rollers and the center of the cutterhead. I didn't have any noticeable snipe on my 12.5" dewalt planer with straight knives, but I had really bad snipe on my 15" grizzly planer with a spiral cutterhead until I made adjustments. When I had snipe with the spiral cutterhead, there was still a "straight line" about 3" from the end of the board that marked where the snipe started/ended.

The nice thing is that you don't seem to have a snipe issues on your new planer. Regardless of the actual cause that is something to be happy about!