Sedgwick CP planer query

[goldfinchbrookes]

Hi all, new to the forum and have learnt a lot, thank you.
After lots of lots of research I lucked out this year and got a 2022 model Sedgwick CP with spiral block for a very good price.
It's the first planer I have used and certainly fits with my philosophy of buy once cry once.
Anyway I'm having an issue when trying to edge joint my boards where I get snipe on the final bit of timber. Anywhere from 10mm long to about 50mm long.
I didn't know if it was a technique issue but it was suggested to me the outfeed table could be too low?
I believe the outfeed table has some adjustment.on this newer model. I haven't messed with it at all since purchase and im certainly not an engineer.
The manual says there is adjustment but not instructions at all as t how to do it.
Any suggestions welcomed.
I've attached photos.

 

[Fitzroy]

Low outfeed table and technique can both result in snipe. What is happening is that there is a gap, often imperceivable, between the board and the outfeed table as the board leaves the infeed table it drops this fraction resulting in snipe. I like to set up my outfeed table so that the knives 'drag' a steel rule by 3-4mm. Stand a steel rule on edge with most of it on the outfeed table, rotate the block by hand (unplug first) until one of the knives lifts the ruler and moves it towards the infeed table, as the block continues to rotate it will put the ruler back down, if it moves it more than 5mm the outfeed is too low.

If your movement is less than 3-4mm then I'd be thinking about technique. I have found that surface planning a board with a bow can result in snipe if the balance of the board changes as the board comes of the infeed table.

Looking at your machine to raise/lower the table you would need to loosen the two vertical bolts holding the outfeed table, then adjust the horizontal bolt such that you advance the lower wedge, thus raising the table, then retighten the table down.

If you have some shims/feeler gauges you can rest the ruler on these and perform the movement test to understand how much you need to raise the table by. Also I would test on both the left and right side of the outfeed table to see if they are level and need the same adjustment.

 

[goldfinchbrookes]

Low outfeed table and technique can both result in snipe. What is happening is that there is a gap, often imperceivable, between the board and the outfeed table as the board leaves the infeed table it drops this fraction resulting in snipe. I like to set up my outfeed table so that the knives 'drag' a steel rule by 3-4mm. Stand a steel rule on edge with most of it on the outfeed table, rotate the block by hand (unplug first) until one of the knives lifts the ruler and moves it towards the infeed table, as the block continues to rotate it will put the ruler back down, if it moves it more than 5mm the outfeed is too low.

If your movement is less than 3-4mm then I'd be thinking about technique. I have found that surface planning a board with a bow can result in snipe if the balance of the board changes as the board comes of the infeed table.

Looking at your machine to raise/lower the table you would need to loosen the two vertical bolts holding the outfeed table, then adjust the horizontal bolt such that you advance the lower wedge, thus raising the table, then retighten the table down.

If you have some shims/feeler gauges you can rest the ruler on these and perform the movement test to understand how much you need to raise the table by. Also I would test on both the left and right side of the outfeed table to see if they are level and need the same adjustment.

Thank you very much for this. Just before I go ahead, does this drag rule apply just the same for the spiral head blades?

 

[goldfinchbrookes]

Ok so I've given it a go with very mixed results. It's super stiff to move the spindle so that maybe explains the differences. It ranges from about 3mm drag to 8mm. Unsure what to do now haha

 

[Fitzroy]

I've no experience with spiral heads, but I can't think why the drag method would not work. It looks like you have slightly more drag on the side nearest the fence, is the snipe worse when surfacing a board on that side?

Personally I think I'd try to raise the side nearest the fence by a hair, like a 1/4 turn on the adjustment wedge, so see what effect it has on the snipe and the drag measurement.

 

[goldfinchbrookes]

Yeah that makes sense. I'll do some tests and report back. Thank yu

 

[deema]

First off, all PT will produce a small amount of snipe when they are set up correctly. The cutter must take a small amount of wood off otherwise you end up planning a wedge. So, the question is how much smile is acceptable? Well, the test / specification of Sedgwick for the drag test creates a smearing that when achieved highlights what to expect. Yoi can see it and you will be able to feel it. The dilution is typically to either make abiut 100mm or 4” allowance that will be cut off, or post PT plane or sand to eliminate.

To carry out the drag test you need new cutters / cutter face. As the cutters are used the sharp edge wears away making the amount protruding less resulting in a reduced drag. So, you should only ever adjust the outfeed with new face / cutters installed.

You can with some simple maths work out how much the cutters should project about the outfeed table. You can then use an engineers clock to set the height of the outfeed table. This is for me the best way of setting the machine up. You really also need a straight edge to setup the outfeed table that long. A straight edge is not the same as say a level, or a piece of ‘straight’ wood. You are looking to adjust the outfeed to a few thousands of an inch or about 0.1mm over the length of both tables, that putting it mildly is six tenths of nothing!

 

[deema]

Have a read through the following thread, we go through how to setup PT tables. It’s basically the same for your PT.

https://www.ukworkshop.co.uk/threads/sedgwick-mb-planer-thicknesser-full-refurbishment.136008/

 

[goldfinchbrookes]

Thank you Deema. If I understand what youre saying 100mm of snipe is to be expected? This is a real surprise to me and seems very wasteful? I'll have a read of your thread, thank you. Really trying to sort this asap as getting behind on my jobs now.

 

[Cabinetman]

I’m sure Deema didn’t mean that lol.
Also when using the machine put a lot of downforce onto the wood where it emerges from under the bridge guard as the end of the board is passing the cutters, or in other words towards the end of the cut press down even harder on the outfeed table. This will reduce the snipe, to nil on a well set up mc.
Ian

 

[Fitzroy]

On my surface planer (Wadkin BFT9) the workpiece comes off the planer with no snipe that is of consequence. If I hold the workpiece up to a raking light then I can normally discern the snipe but it is less than will be sanded off during final finishing. My machine does however have easy (hand wheel) out-table adjustment and I will occasionally tweak this if I see any snipe occurring.

When you say you are getting snipe, how much is it. Can you take a photo of what you are getting.

 

[deema]

The cutter makes a series of scollops, in a perfect setup the successive scallops will start and finish exactly together. This will result in zero snipe. However, this is impossible to achieve / sustain, so, if you set the cutters lower than this ideal, as you plane the cut depth will become reduced due to the part in between each scallop start and finish not being cut. This is what causes a wedge shaped cut from one end to the other of the stuff you’re planning. This is highly undesirable and produces a poor finish too. So, the cutters are usually set a little bit too high, which takes into account the cutters becoming dull and ensures you don’t cut a wedge. By setting the cutters slightly too high you will have snipe, how apparent it is, depends on how high you’ve set them.
If your knives are set slightly too low creating a wedge putting a lot of weight on the stuff as it passes over the out feed table causes the intersections between the scollops to flatten and reduces the wedge effect.

 

[goldfinchbrookes]

Thanks for your replies everyone.
The snipe is too shallow to photograph im afraid. It's only just possible to feel it with your finger.
However when jointing the gap is clearly visible with light shining through.
I tried the method of pressing down hard at the end of the cut and this did actually make a good bit of difference.
Previously I have been focussing more on keeping it square to the fence than pressing down, but after following your advice i managed to get a good enough (invisible) joint between the boards.
I'll play around more tomorrow and may have a go at raising the outfeed the tiniest bit.
Thanks all for your help.

 

[Jake]

The cutter makes a series of scollops, in a perfect setup the successive scallops will start and finish exactly together. This will result in zero snipe. However, this is impossible to achieve / sustain, so, if you set the cutters lower than this ideal, as you plane the cut depth will become reduced due to the part in between each scallop start and finish not being cut. This is what causes a wedge shaped cut from one end to the other of the stuff you’re planning. This is highly undesirable and produces a poor finish too. So, the cutters are usually set a little bit too high, which takes into account the cutters becoming dull and ensures you don’t cut a wedge. By setting the cutters slightly too high you will have snipe, how apparent it is, depends on how high you’ve set them.
If your knives are set slightly too low creating a wedge putting a lot of weight on the stuff as it passes over the out feed table causes the intersections between the scollops to flatten and reduces the wedge effect.

What rpm is your planer?

 

[Jake]

Mine's circa 7000rpm, or 115 per second, but two blades so say 230 scallops per second. If each scallop is say 5mm (guess, haven't measured) you'd need a feed speed of over 1m/s to get any land between scallops and that's just not happening IRL. In reality I can see tiny 'scallops' when pushing timber through too fast, but those are where scallops have overlapped but not enough times.

 

[Cabinetman]

Not sure about anyone else but I have always put a smoothing plane over the edges to be joined after the planer anyway, and I have a large pro SCM machine. Just seems the right thing to do.