Back to Basics - I can't saw straight

[woof]

Pretty embarrassed admitting this, but my last two projects I have been struggling to rip anything straight on the tablesaw.


I am using the auxillary fence on the axminster cast iron tablesaw AW10B2. WHen I line up rip boards for glueing, the middle and most of the length of the boards meet nicely, but the start and end are slightly shorter and need considerable pressure to get the panels together. Guess this means the wood is drifting from the blade at the start and end of the cut.

Is this due to:
1. Wrong technique? Am I pressing unduly against the fence at start and end of cut?
2. The auxillary fence - maybe I should stop using this and remove and just use the full table length fence
3. Incorect set up. I havent checked the alignment of blade/fence recently, but I find it hard to think that this could lead drift at start and end of boards.
4. Wood tension. This is what I though at first as I tend to mostly cut oak. However, last weekend I was cutting some old pine - with same results.

Help!!!!!

Confused from Sussex

 

[OPJ]

How dry is the timber you're using? Has it only been sat in your workshop for a short time? A higher moisture content (particularly when it's trapped in the middle of a wide board) could account for any movement as the stresses are released.

Is the riving knife set correctly behind the blade?

When setting the fence, do you line it up correctly with the last cutting tooth?

Normally, I wouldn't personally go for a finish straight from any saw and would take each edge to my planer thicknesser.

 

[woodbloke]

I assume then that you're trying to glue boards together straight from the table saw blade? :? This in never going to be accurate enough as edges should be shot in with a hand plane so that they're slightly concave rather than convex, which is what I think you have there
edit: or at least as Olly says, passed over the surfacer - Rob

 

[ByronBlack]

One needs a jointer, or a jointing setup on a router-table for edge-joints (or a nice No.7 plane). TS will only give you so far a straight edge.

 

[woof]

I didn't realise you couldn't glue straight up after the saw :shock:
I do have a planer/thicknesser - and even hand planes I bought recently!

Riving knife set up - good point, and I will check.

Does nobody glue up straight after cutting?

 

[newt]

I agree with all thats said, however as long as the edge running on the fence is straight in theory, you should produce a straight cut. I suspect it may be technique with the aux fence. You could try the full length fence, but be very very careful of kick back and check first that the riving knife is centered on the blade and at the correct distance from the blade.

 

[woof]

How dry is the timber you're using? Has it only been sat in your workshop for a short time? A higher moisture content (particularly when it's trapped in the middle of a wide board) could account for any movement as the stresses are released.

One batch of timber from an outside store from the merchants - only dried briefly (week or so) indoors. The other timber from unknown source. But your point is well made, and it isn't the oak I have drying indoors to make all our internal doors. I am making 8 doors with this so want to make sure I don't struggle as I am at the moment. Could be that the problems are exacerbated due to movement.

Is the riving knife set correctly behind the blade?

Actually I didn't check that - thanks I will

When setting the fence, do you line it up correctly with the last cutting tooth?

No - set it up with the front tooth of the blade - the first tooth out of the table. Which is the last cutting tooth - is that tooth at the height of the wood?

Normally, I wouldn't personally go for a finish straight from any saw and would take each edge to my planer thicknesser.

Well this does seem to make sense and is the consensus? Also similar to my experience - the boards I have just cut I bought as rought sawn. Planed one edge, and thicknessed the two flat parts of the board. The final (conver) edge I prepared by ripping. The planed edges fit fine and straight (although a little rippled - ?my blades are blunting now?) but the problems come from the one ripped surface.

Many thanks, Mark

 

[Chems]

Does nobody glue up straight after cutting?

People do glue up straight from the table saw, a lot of saw blades the really good ones now claim a "glue line rip" I've could join straight off my saw but I don't always put them through the planer once before they go together.

 

[woodbloke]

Does nobody glue up straight after cutting?

No. Timber IMO, should always be planed before gluing. Even with a very good saw blade there will still be some marks left from the teeth on the edge which will prevent, or at least hinder the joint going together. As was said earlier on, edges need to be very slightly concave (by the thickness of a fag paper :wink: ) which can't be done straight off the saw and is almost impossible to do on a surfacer. A couple of stop shavings with a No7 will give you the concavity on the edge to ensure that the ends of the boards are always in tension when glued - Rob

 

[Niki]

I would like to add...

As I understand, you are using "Auxiliary fence" or what is also called "Short fence" and sometimes "Half fence" that are the same.

You should extend the fence up to the centre of the blade (the Arbor centre).

In my opinion, is very important to have more of the fence at the Infeed side for good support before the wood enters the blade front teeth and use feather board to hold the workpiece tight to the fence.

Have a look at this post, I got very straight pieces (in one of the pics, you can see them attached side by side.
https://www.ukworkshop.co.uk/forums/view ... highlight=


As for the fence alignment, have a look at this post...I know that it's not the "Normal" way but it works like a charm for me...
https://www.ukworkshop.co.uk/forums/view ... highlight=

niki

 

[OPJ]

You should extend the fence up to the centre of the blade (the Arbor centre).

I'm sorry Niki, but, I disagree with that, although it does have relevance when cutting thicker timber (eg. 3" thick on a 10" blade). The end of the fence should be in line with the last cutting tooth at the front of the blade - once the timber's past the last tooth, it has no reason to contact any part of the spinning blade.

To get this correct, first, place the timber to the side of the blade and lower the guard (and blade) so that it is as close as practically possible without fouling the timber or exposing too much blade. Look for where the circumference of the blade meets with the top face of your timber - this tells you where the last cutting tooth will be and, where your rip fence should finish.

I admit that it takes a bit of practice to get the last 12" of a cut straight and true with a short fence but, ALWAYS use a push stick!

 

[Niki]

Hi Olly

You don't believe that I'm so "knowledgeable" to decide by myself where to put the fence...

A few weeks ago, I've sent an e-mail to Metabo Engineering department about the kickback danger and the use of "Short fence".

Here is the Metabo reply...

---------------------------------------------
Dear customer,

thank you for your email regarding the setting possibilities of the rip fence.

Reactive woods (not dead woods) can move to the side just after cutting. That´s why there might be the risk of a kick back if the rip fence is set in the long position.
In order to minimize this it is recommended to set the end of the rip fence to the saw blade centre (short position).

For sawing dead wood like chipboards it is recomended to set the rip fence in the long position in order to achieve the maximum guiding length.

The riving knife is absolutely necessary and the correct position of the rip fence has to be chosen according to the wood!

If you have further questions please feel free to contact me.
Furthermore enjoy woodworking!

With best regards

-------------------------------------------
Florian Fischer
Produktmanager Holzbearbeitung
Product Manager Woodworking

Phone: +49 (0) 70 22-72-2529
Fax: +49 (0) 70 22-72-2074
Email: [email protected]

metabo
work. don't play.
-------------------------------------------

So far, that's the only official source that I have...I could not find any HSE reference except that they show on there drawings a short fence (on the HSE Woodworking sheet No 16 (rev) but they don't specify the exact location of the rip fence - pic below)

After I've got the reply from metabo, I made a few pics for some American forum trying to convince them about the short fence but......nah, it did not work...they are afraid that the wood will divert and kickback if there is no long support (fence) pass the blade....

Personally, I feel very confident and I did not have any problems to steer the last part...

Best Regards
niki

 

[Digit]

Does nobody glue up straight after cutting?

Yes! Under certain circumstances. Predominately it depends on the length of the timber. Mitres I glue up from the TS, a metre length might be a different matter.
I have fitted my SIP TS with an adjustable short fence that slides along the main one and I have tried ending it at different points and the centre of the blade seems to work for me.
Also the fence is set up to be a few thou closer to the blade at the front than it is at the back, this seems to prevent the equivalent of 'snipe'.

Roy.

 

[Steve Maskery]

I think Sam Maloof does. IIRC he glues up his walnut seat blanks straight off the saw.

Personally I always rip with a short fence, finishing somewhere between the last cutting tooth and the sawblade centre(after all once the wood is cut, it's cut).

Very rarely would I glue up without a pass or two of a No 7.
S

 

[OPJ]

Hi Niki and thanks for posting this information.

Sorry, I didn't mean to question your knowledge or insult your intelligence.

Setting the rip fence isn't as crucial as something like setting your plane knives in the cutter block so, I guess there's a bit of leeway. The most important factor is to ensure the timber cannot become trapped between the fence and rising teeth. If it works for you then, I guess there is no problem.

 

[Niki]

Sorry, I didn't mean to question your knowledge or insult your intelligence.

Oh no Olly, I did not take it that way...as you noticed I said it very clearly that I don't have enough knowledge to "invent" the correct fence position...

Before I got the Metabo's e-mail, I was setting the fence to 1"~2" beyond the front teeth (that's what I read on the internet) and it also worked without any problems but now, I thought to myself "maybe those German guys that made the saw know better"...

Best Regards
niki

 

[Benchwayze]

My only 'table-saw' is the attachment on my Coronet Major Lathe.
That has a short fence, the thinking being that once the timber has passed the back edge of the blade it needs room to move open, as wood often does coming off the saw.

At times, I've had to put wedges in the kerf, but usually the wood bows open as it's cut.

Anyone who knows how small the Coronet Major's table is, would think twice before ripping 12 feet of 12" x 2". However, with someone to take off the board, I used it regularly for such cuts, (before I had a bandsaw.)

I have never had a kick back as such. I have stopped the saw at times, but then with just a 1 hp motor that's easy! I use the bandsaw for 90% of ripping now. True it won't dimension so well, but I have the planer-thicknesser. In my poky garage, I am happy enough to plan for a little more waste.

In short, I don't really like table-saws these days, at least not the ones I could afford to buy!

Regards John

 

[Grinding One]

Niki,over here we have Board buddys,they mount onto the fence keeping the boards pushed down on the table top,they have wheels on them so wood rolls under them keeping the wood moving...Delta also has motorized ones.No need for a short fence.We have a magnate with a bit of metal on an angle to keep the board pushed into the blade as well...so the only way the board can go is thru the blade.I do not have kick back anymore since useing this system.

 

[woof]

Update ... if anyone is interested.

Moving the auxillary fence to different positions (start, mid blade nr arbour, and end of blade) did not seem to cure the slight convex rip.
Removing the entire auxillary fence did lead to a beautiful straight cut using the main solid axminster fence. So it may still be technique related but it could perhaps be the auxillary fence. THe auxilary fence does not have the "meat" of the main fence; also notice that the auxillary fence is held much more proud of the ci table - much more so than the main fence. Perhaps these factors might mean that too much pushing against the auxillary fence gives a different register relative to the blade at the ends and in middle of the board. I hope that makes sense?

One thing I notice is that ripping using the main fence, you do meet much more resitance (although not fighting the blade - but maybe need lubricate the table soon), and certainly I am far more wary of kickback as it seems much more of a likelihood than with the auxillary blade.

Anyway, though I would let you know that I CAN cut straight!!! \/ \/ \/


Now why can't I plane straight!!!! :?: Seriously I can't ... but will look for help again if i don't sort it soon.

Thanks all muchly!

Mark

 

[joiner_sim]

The surface planer in works cuts on a taper.....
This is because the blades are getting blunt, and also the tables aren't levelled up properly.