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Just bought a benchtop planer and I am getting infeed snipe. None on the outfeed. Adjusted the infeed tray and no change. Feeding nuts to butts does nothing.
My machinery designing brain is telling me that the first roller is too weak. I know that snipe is really hard to completely get rid of but
I have no experience with planers so any guidance would be appreciated.
Snipe is just something you have to live with.
I've used the biggest, and best planers around.
They all snipe.
You just have to cut your material long, and clip the ends.
Unless you're in a big mill shop with a profile sander.
Only solution I've found is to have a board literally riding into the planer "pushing" the board in front of it.
It minimizes the snipe on the tail end of the first board, and the start of the second.
Benchtop is pretty broad description. Is it a single head thickness planner with straight blade knives? If that is the case, the most you should be taking off in one pass is 1/16" and you should have a feed rate of 16 marks per inch. That should take care of a lot of snipe if you run it within it's parameters. Assuming knives are set right and feeder tensions are correct. A feeder table helps as well. All things aside, for front end snipe, you should always plan your runs and use a feed board or butt them up like Joey said.
It's a Craftsman 12 1/2W x 6" thick max. I looked at planer reviews and for what I want this one got good reviews for the price. It's a straight dual blade at 8000 rpm. Couldn't tell you the feed rate. The heaviest cut I'm taking is about 1/32. Butting up boards on the feed didn't have any effect. I was planing 3/4" stock. When I tried some 8/4 the snipe was less than a 1/64 so I guess I shouldn't complain. It's about a 2" long snipe and is actually on both ends now that I look closer. I got it for doing cabinet door rails and stiles which it should work fine for. i don't have that many to do and I didn't want spent $500 or so on a DeWalt. This one was $300.
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My old boss is big into wood working . He deals with some pretty expensive pieces of wood that he explained to me you can't just add 3 inches to both sides or every project would cost a fortune. I remember him using double sided tape and some plywood runners that extended the 3 inches longer then the project piece.
I have heard of that method too. Depending on what you are doing, you only have to add waste to each end and then get several pieces out of that one. It's typical of working with hardwood.
Accept it. Add the snipe length for waste and relax.
If you’re cutting tenons on the end then you can take that into account, add a little less and let the snipe come out of the tenon.
Does it have adjustable feed rate? If it does, what I was referring to was the knife marks on the board. Measure an inch of the board and count the knife marks within that inch. Assuming the knives are set at 25 degrees, the sweet spot for speed would be to have 16 to 20 knife marks per inch. If you have 8, 10 or 12 marks per inch you are going way to fast and will have more opportunities for undesirable results such as snipe, chatter, chips and tears.
Feed rate not adjustable. The specs do not give that info either. I checked the DeWalt DW735 and it is a dual speed. 96 and 179 cuts per inch. That does not make sense with your numbers at all.
I found that the industrial size planers were rated in feet per minute, which is only production rate and needs more info to calculate cuts per inch. Cutter rpm and cuts per rev. I have always worked from recommended chip load or feed per tooth or feed per rotation (Lathe) which are all inter related. Cuts per inch also tells you chip load. 96 cpm is a .010 chipload and 179 is .005 chipload.
If i get bored I will put a piece of stock in and manually rotate the cutter. A dial indicator on the end of the stock will tell me what the chipload is.
I don’t see how feed rate can impact snipe. Finish, yes, but snipe is the board lifting higher into the blades before the second feed roller grabs hold.
On those planers, does the cutting drum spin to pull the wood in or push the wood back? IE: climb cut or conventional? I've never used one.
I think it more relates to a conventional cut. The material is forced into the blades which are spinning opposite the board travel.
Conventional. Pushing against the feed.
That's what i am finding out. Feeding boards nuts to butts doesn't solve it either. BTW, my chipload is .015 which calculates to 20 fpm feed rate at the stated rpm of 8000. It's also 66 cuts per inch.
You can mitigate it slightly by kind of raising/supporting the tail end as you feed the board in. But you’ll never stop it entirely. I’ve had three planer/thicknessers (we use combined jointers - as you call them - and thickness planers over here), each rising in cost to my current one, which was pretty expensive They all did it.
Far simpler to just accept it and cut it off afterwards. There’s a lot of waste in prepping timber anyway. Another three inches on the end won’t break the bank.
Cuts per inch and knife marks per inch are 2 different things. Knife marks per inch you can visually see and easily measure. It is a direct result of cutter head RPM and feed rate. Any machine such as a planner or molder spinning knives in a circle while feeding wood through that circle will have knife marks.
Here is a link I found that gives a pretty good explanation of the math equation. https://www.mr-moulding-knives.com/information/moulding-knife-marks
It sounds like you are limited with a set feed rate, so the best you can do is tighten your inner shoe and try to place the board in as level as you can. If your feed rate was adjustable, it probably wouldn't eliminate end snipe but it would reduce it. The reason it happens is because the board is hitting the tooling to fast and the knives are lifting the board before it can be grasped by the second shoe. Proper feed rate would limit it's desire to lift the board.
I don't mean to be argumentative but cuts per inch and knife marks per inch are the same thing. The calculations from the link you provided are the same ones I use.
My machine:
Feed rate = 20 feet per minute = 240 inches per minute.
RPM = 8000 x 2 cutters = 16000 cuts per minute.
16000/240 = 66 cuts or knifemarks per inch.
The machines used in the link only have 1 blade cutting for some reason and also use 6000 rpm's. With a feed rate of 30 feet per minute,
Feed rate = 30 FPM = 360 IPM.
RPM = 6000 x 1 blade = 6000 cuts per minute.
6000/360 = 16 knife marks or cuts per inch. It actually seems course as hell until you work out the geometry.
Assume a 2" dia cutter at those feed rates makes the depth of each knife mark about .00045" spaced .06" apart. Unless it was highlighted some how, I couldn't see it.
Those dimensions can be worked out using trig but that's too hard. I draw it out on CAD and just measure it. Fuck trig.
I remember just out of school one time. My dad wanted a roof built over the pool. It was going to be a clear arc plexiglass roof. He asked me to figure the exact length of the plexiglass panels. I broke out the trig tables and pencil and paper and went to work. I had the distance across and rise he wanted. A while later I came out with an answer. Mean while the contractor (my best friend at the time) had come by. He just started drawing it on the drive way with chalk and measured it out. LOL. I learned a lesson that day! Because you learned something in school, doesn't make you smarter than people that acquired experience by actually doing things.
TM
Pit Row
I don't think I could even do it using straight math now. With cad it took 2 minutes plus I get the visual. I even have to think about calculating feeds and speeds if I haven't done it in a while.
Busted out the old, beat up, worked hard, put up wet, delta planer today.
Making splines for joining/seaming large alder panels.
This poor thing is closing in on 2 decades of abuse.
Constantly keeping sharp knives, keeps it cutting like new.
Even down to 1/4".
I'm not being argumentative either but honestly there is nothing to argue about. They are 2 different things. LOL You did the calculations. Look on a board your planned, grab a tape measure and see if there are 16 knife marks per inch. Go to Lowes or home depot and look at any piece of molding or milled board and you can see the marks. Theirs will be in the 8-10 KMPI range. Call them mill marks if it brings more understanding. (I'm not being sarcastic) That is what they are. But they are called knife marks per inch. Not knife cuts per inch.
The reason why the calculation is for 1 knife is there is always a dominate knife. Even a router or shaper bit has a dominate side. Anything with a spindle and a feed. If you somehow was able to achieve 66 knife marks per inch on your planner you would burn up your knives in minutes.
Looking up the knife marks per inch equation from a knife manufacture kinda made me chuckle because it brought back a memory. I used to be heavy into woodwork and grew up with my family owned cabinet face and molding shop. We manufactured stile, rail and raised panels. We also manufactured furniture and at one time had a sawmill and dry kilns. I mostly ran and maintained Weinig and SCMI 6 head molders. I did most of the knife grinding and setting up the heads and setting up runs. Years later I found myself in Indonesia renting space from (at the time) the second largest molding factory in the world. I manufactured furniture parts there and did consulting work with the factory on the molding, finger jointing and optimization lines. The funny thing about that math equation is that even though what we did was technical it was still hands on. My Dad would always get on to me for making things to complicated (like equations). When I found myself in Indonesia, in the second largest molding factory in the world, I got the biggest chuckle. We had 24 molders in which 4 at a time had to run in unison with one another. They ran in unison with profile sanders and every 45 minutes there was a bottleneck. Times that by 6 lines and it was a huge problem. They were these huge German machines. I was way over my head with these Indonesian engineers walking all around with their calculators doing their figures in metric. We still did decimal on the machines which is the same as here but rates were all metric. They couldn't get a consistent equation they could input into multiple machines with accuracy. Machines differ just a little. Knife profiles differ just a little. I went down a line and checked each machine with my standard ruler and noticed the differences between the knife marks per inch on each machine. They varied something like between 14 and 18 and some of the settings were in the half marks. Meaning they didn't end on the inch. After determining the problem, it took about 10 minutes to adjust them into unison. But it was on the inch and not 2.54 mm. which was funny. The line I adjusted ran overnight with no bottlenecks and was part of the overall solution. As far as I know, I'd bet my ruler is still floating around that place. Physically counting marks was the only way to achieve unison. Just like Dad said. It really did have me tickled. Looking up those equations reminded me of that. Not in a million years would I ever use them.
OK now it becomes a bit clearer. There is absolutely a dominant knife in a planer like this so you are correct that regardless of how many knives are mounted, only 1 will leave a mark. So in my case the KMPI would be 33 and not 66. 8000/240.
Thanks for clearing that up.
BTW, I can hardly see the marks on the piece that I cut and there is no way I can count them. Doesn't really matter I know what it is. I will check the molding at HD next time I go there. It will probably be easier to see at 16 KMPI.
Is having a "Dominate Knife" by design or by lack of quality? So both are cutting but one cuts deeper? And what would happen if both cut equally?
TM
The knives are field replaceable and there is really no way to get the knives exact. Maybe if they were ground in place you could but it's really not necessary. Even at 16 kmpi the peaks left in the stock are minuscule. Mine is running at 33 kmpi which means that you will never see them. Two passes with an RO sander and 150 grit and they are gone. The added blade just reduces the force required to push the stock through. If they were within .005 I would be shocked. I'm not even sure how accurate the inserts are in a 3 or 4 inch face mill. Be interesting to find out.
I have a indexable countersink. If I change the insert, there is a change in the part if I don't change the stop. That could be because the inserts are not the best quality, I don't know.
So what you're all telling me is that if I made a planer that didn't produce snipe, I could make a lot of money. So why isn't anyone making the planer that the drum turns the other direction? Is it a safety issue that the cutter will "pull" the material through unwantedly fast? When cutting metal, a climb cut is always better than a conventional. The tooth actually starts being able to cut better. But the first problem seems to be with a conventional cut , the last bit of cut is in an upward cut lifting the material into the cutter deeper. As soon as you lose support, the end of board lifts creating the deeper cut that you call snipe.
Also, I saw this on the side of the dewalt, 179 cuts per inch and 96 cuts per inch. so if you have a dominate blade that's still 90 marks per inch or 48
I put a helical head on my dewalt, still got snipes on the ends but always planned for it. Haven’t used it in years now. Always use my Powermatic 15” with the helical head, that thing eats!
I thought about the conventional cutting and pulling the stock into the cutter . Keep in mind that I have a 2" diameter cutter that is only cutting .032 depth. It's much more of an issue as the cutting depth, in this case, gets deeper. At .032, the cutter is doing way more pushing than it is lifting. At 1" depth, you would be lifting like a mofo. It's pulling straight up at the end of the cut. At .032 the uplift is minimal. I was thinking that the problem was the infeed roller and pressure. If you take a 3/4 board and a 2' diameter roller and push down, at some point, with enough force, it's going left the unsupported end. Actually bending the board. I threw a piece of 2 x 4 in there on edge thinking there is no way it's going to bend it but the same amount of snipe was still there. The problem is that I need more beer in order to figure this out but like others have said, it's basically a snipe hunt, if you get my drift. Maybe that's why they call it snipe. You're wasting your goddamn time.
If I'm not mistaken, that planer has 3 blades. If that's the case then its actually 32 and 64 kmpi. I really don't know what 64 get's you. A really slow planer probably. It's probably 20 and 10 feet per minute feed rate. Like I said, I''m getting 33 and it feels like glass. Flick it will be along at some point to straighten our asses out. He seems to know his shit.
I looked up the powermatic 15". That's the real deal.The DeWalt is a toy compared to that beast. Do you still get snipe with that one too?
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