Feather roller - version II, prototype.

[Niki]

Good day

Very soon I shall have to cut long Oak boards.

Today, I was working on prototype of feather roller with 2 rollers.
Please remember the roller tilt down as in the first post.

I wood like to here your opinion and if you have any suggestions for improvement.
Just have in mind please, that I like it simple and with in-hand resources.

I did not try it yet except dry run that looks and feels very good.

Please go this post

https://www.ukworkshop.co.uk/threads/wow-im-in-love.120811/
Thanks
niki

 

[Scrit]

Hi Nikki

What you've arrived at is quite similar to the Aigner side pressure units sold by Felder and others. They work quite well on straight edge stuff, but aren't really much use on waney stock. A couple of comments: with such long boards you should really make sure that you fully support the stock on a roller support or two at the infeed end of the saw, and at the outfeed end you really do need a run-off table to suport the timber. Without support long pieces can bow in cut and it can become quite dangerous very quickly. For ripping I'd alos suggest using an auxilliary fence on that long through rip fence to give you in effect a short rip fence. With the set-up you show in your photos you're running the risk of any stress in the stock causing the wood to jam between the fence and the blade - a common source of kickback.

Happy sawing

Scrit

 

[newt]

Looks good Niki, I think I will give it a try. I notice that you have a PK200, I have had mine a couple of years. I have a few issues with the set up but I had a significant problem with the riving knife. I could not get it to be exactly in the centre of the saw kerf. It was always on the right of centre as you look at the machine. I tried a number of things but in the end I had to be quite radical. As you know the riving knife (RK) is attached to an adjustable metal block with 2 screws, the adjustable block allows you to alter the gap between the RK and the saw blade. What I had to do was to add some shims between the metal block and the support carriage for the motor. Sound easy but removing the metal block is quite difficult. You have to tip the saw upside down and undo the 2 screws that hold the electrical connector to the motor you can then unscrew the block from the normal adjustment position turning clockwise to loosen, when the block is free you can carefully remove it and you will see there is already a shim behind the block. I made a replica from half mil shim and re attached the block which is a bit of a fiddle. I also had a problem getting the plastic cover for the electrical connector back in place. I should make it clear that you have to remove the the electrical connector so the the metal block adjustment screw can be fully undone from the front if you try and fully unscrew with out doing this the head of the screw will be pushed into the back of the electrical connector causing damage.

With the RK dead centre on the Kerf it really did make a difference to the finish on the cut edge and it has improved the accuracy. There are a number of other tweaks I could mention if you wish.

 

[Niki]

Hi Scrit

Thank you so much for the comments.

Felder, I only know the name (and the price) but I've never seen it.

I have an infeed and outfeed tables, each 1 meter long so its ok.

As you advised, I will use the short rip fence that was supplied with the saw (EB PK255)

Hi Newt

The saw is PK255, I've never had problem with the RK, anyway, the saw is still on guaranty (3 years) so if ill have a problem its just a phon call, they have superb service here.
Thanks for the info.

Thanks
niki

 

[devonwoody]

Looks as if you have put a lot of thought into that bit of equipment, I assume a blade guard will hold down the board to the table, would it also be useful if your guide also had a vertical pressure point between the wheels?

Stress and Tension on wide boards I found in the past on tablesaws can be enormous and soon knocks your equipment into unsatisfactory condition.

 

[Niki]

Thank you Deonwoody

You gave me something to think about, the vertical pressure.

Usually, the Oak boards that I'm using are 250~300 mm in width.
I already cut 1 cubic meter of them and did not noticed any difficulties but, as they say, "there is always the first time"...

niki

 

[Scrit]

I assume a blade guard will hold down the board to the table

Try that on many table saws and you may find the guard gets pulled straight off. Even worse try it on saws with SUVA-style overhead crown guards (such as a panel saws) and you'll soon discover that they can't give any downwards pressure at all. Crown guards are just that, guards, and you really shouldn't assume that they will also act as pressure pads. Fortunately stress being relieved in cutting normally manifests itself as the timber bowing away from either side of the riving knife, or trying to wrap itself round the back of the riving knife rather than bowing upwards off the saw table. If stock is so badly out of whack that you have to consider using a down pressure pad to resaw it on a table saw then it's either firewood, or you need to square it first on either a band rack or a planer. And if it needs holding down part way through the cut because it's lifting away from the table then you need to stop the saw, reverse out of the cut then figure out another way to complete the cut as it is becoming dangerous to continue.

Scrit

 

[Niki]

Thank you Scrit

I learnt something today.

Just a few minutes ago I saw this post in other forum.

I copy/past it as it is, just to show how correct you are.

"Finished with cut, reach to turn off saw to the left and the finish size piece of plywood launches just East of my crotch. It hurts like ****, but I would say I was lucky.
-The guard is shattered on one side and the right pawl is broken off and on the floor."

niki

 

[devonwoody]

Niki, I hope you are not upset at the following hijacking of your thread but Scrit who obviously knows and has experience of woodworking machinery makes a comment above which to me has some contradition.

If timber lifts up when being sawn on the tablesaw the guard surely must also have some purpose in stopping the lift proceeding higher and then over the top of a blade?

On the Triton system there is a pressure trigger under the blade guard that gives slight downward tension. The guard on a Triton is attached to a splitter not the riving knive.

Scrit are your thoughts reacting to a riving knife?

 

[Niki]

Not at all, Devonwoody

Actually it's interesting for me too, but if you read the above post the guy said:

"The guard is shattered on one side and the right pawl is broken off and on the floor."
Not a word about the splitter that was strong enough to resist the impact.

I think that you have to put it on test (but don't) how much the guard (and the anti-kickback pawls) will stop this "rocket" and protect you.

Scrit
Do you think that induction motor is better than universal motor in case of kickback?, I noticed that sometimes when the wood is not flat, the saw blade just stalls and stops without any kickback.

Cheers
niki

 

[Scrit]

If timber lifts up when being sawn on the tablesaw the guard surely must also have some purpose in stopping the lift proceeding higher and then over the top of a blade?

Not really DW. Many crown guards are held on top of the riving knife by a single bolt, sometimes in a slot rather than a hole. To illustrate the point here is the standard riving knife from a Felder K975:

Which I believe is pretty similar to that used on other Felders and some of the Hammer range. The SUVA-style safety guard commonly used on panel saws is incapable of providing any down pressure at all:

If you are cutting reaction timber it does tend to react in a single plane - either parting away from the riving knife, or pressing inwards on it and it's the possibility that work can jam between the blade and the tip fence which predicates the use of a short rip fence. This reaction isn't just confined to solid timber either - I've had it happen on MFC and plywood as well and I'm not immune from forgetting myself and getting the odd kickback from time to time which reminds me to pull the sliding fence section to the back!

Do you think that induction motor is better than universal motor in case of kickback?, I noticed that sometimes when the wood is not flat, the saw blade just stalls and stops without any kickback.

I'm not at all sure. I know that having moved "upwards" from 1 HP saw benches to a 7.5HP at present the more power I have the less kickbacks I seem to get - probably because the saw is less likely to bog down in the cut.

Scrit

 

[devonwoody]

Scrit, I was continually getting lift UP last year on a tablesaw, extra short fence was fitted.

 

[Scrit]

I wasn't saying it doesn't happen. But if you are getting a 1-1/2in vertical warp in a 1in thick piece of timber how on earth will you ever plane and thickness that timber to dimension? You are also back to running the risk of a kickback as well. As I may well have said earlier if you see a lot of reaction in the cut that is a good indicator that you need to stop and rethink your sawing strategy - possibly consider cross-cutting into smaller lengths before ripping. I would not continue running this way and expect the crown guard to act as a Shaw pressure guard - most of them are too flimsy for that in any case.

Your timber has already been ripped vertically from the bole at the saw mill and any tension will generally show itself as warping or cupping in the timber in its length as it dries. When I pull out a warped plank I routinely crosscut it into smaller lengths before it goes anywhere near the rip saw - that way I get a lot less problems making rip cuts. Many trade shops have a crosscut or radial arm saw in their timber stores to do just this sort of cut.

Another source of problems is the lack of a run-off table behind the saw to support sawn timber as it leaves the saw. Many of the trade joinery shops you go into have a home made 1.5 or 2 metre run off table at the back of the rip saw to give the extra support needed (and these days it's another legislated thing we have to contend with). Rollers don't really give adequate run-off support IMO. Do you have adequate run-off support on your saw?

At the end of the day there are always going to be pieces of timber which are going to be a problem and are only fit for firewood (or turning :wink: ) because they are so badly stressed that every time you machine them, or every time the weather changes, they are going to move. I have a whole collection of beautifully grained hardwood firewood just like that which one day I'll turn (or if it's cold enough throw into the fire)

Scrit

 

[Losos]

Hi Scrit
It's very interesting to read your comments which are obviuosly made from a proffessional perspective. For myself I'm making notes 'cos I feel rather attached to my digits & not only that, but the nearest hospital is a very long way away

I have noticed a bit of 'lift' especially with thin stock, I put it down to the rear of the blade just picking up the side of the cut made at the blade front.

How to stop it :?: I only have the push stick that came with the saw (Hammer) should I make some with longer 'arms' :?:

Should I have a selection of different types, :?: I was considering making one like Niki showed earlier.

 

[devonwoody]

Scrit, thank you for the time and your past experiences on this subject.

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