Thread: Acute angles on the Table Saw?

The question I would pose is, Why use the table saw? Could you make a jig to hold the material at the correct cant and run it through the thicknesser? I don’t use mdf by the way.

Cheers

Used to do this sort of thing fairly regularly. The trick is to tilt the saw to the complementary angle (90 - the angle you want) and have the "bottom" face against the fence. Stick/clamp a sacrificial piece of MDF to the fence to protect it and to cover the top of the blade.

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That being said, what you need is quite small, so a thicknesser jig might be a better/safer option. Allow plenty extra for snipe at both ends

I'd be adding a small 0.2-0.5mm flat at the 35.75° acute angle so I can use that as a reference edge after the cut has been made. It also overcomes the problems of having a super scary sharp and frail edge.

Its tricky isnt it!

Ive thought of a jig... I think....

Its all the weird angles, plus they are small bits. If it were only for 24 or so Id do them like Yosegi Zaiku bundles, BUT there are hundreds...

Thanks all - any more ideas keep them coming


edit: hehehe. Eureka! If I add a temporary board to my sled at almost any arbitrary angle, say 10° to make the maths easy, then this deducts from the 45° tilted blade. In fact, the tilt of the new board need only be measured, then of the blade can be simply made to be the difference of these two. Just use my digital angle-o-matic. Let me take a picture with a rough-up.

With the table saw . You cut the first one like Elan said . The second cut needs a cradle jig so the piece can be flipped and cut, holding the first cut angle. Otherwise it wants to be falling into the cut and gets messy.
Then you have to remove saw marks cleanly .
How you want to do that ?
Held in jigs and planed then lightly sanded is what I'd probably do.
A shooting board jig made to hold the cut piece with the face needing to be planed facing up . A level rest for the plane on both sides.

Another option may be , If you have a router table . Have a router bit made that cuts the two top angles in one pass. Get some 25mm MDF . Run the shape and cut off after each pass , the saw marks are on the bottom of your sticks . They may still need finishing with sanding in jigs .

The problem there is getting the money back the bit costs for the job size . Carbitool Moorabbin can make the bit.

The perfect job for a spindle moulder, a few heads for choice, and a stock of the right HSS to grind yourself . That's what I would do if the job was large enough .

Originally Posted by auscab

Another option may be , If you have a router table . Have a router bit made that cuts the two top angles in one pass. Get some 25mm MDF . Run the shape and cut off after each pass , the saw marks are on the bottom of your sticks .

I wonder if that might make them too fragile? You'd end up with the MDF version of short grain and I don't think the feather edges would survive.

The perfect job for a spindle moulder, a few heads for choice, and a stock of the right HSS to grind yourself . That's what I would do if the job was large enough .

I wish I took a photo of what MDF did to one of our sets of HSS moulder knives; you could clearly see where the board had run, there was close to 0.5mm worn away.

I think we might be going about this all wrong... Why not just use thicker MDF and have a V-bit made with a 108.5 degree included angle and simply run V grooves on a router table? No cutting, no sticking, just a solid piece ready to be painted.

O' Gnarly Wood Wizards! Ye have helped me!

I love this group for its inputs. Its greeat to get feedback, ideas and nuggets.

In this case, I thought of ElanJacobs' work practice, which I liked, but thought hhhhhhmmmmmmm, how can I make this A Thing (i.e. fart around wasting time building yet-another-jig).

In this case, here are some photos of how it might work. I get to keep all my super-accurate Incras and keep everything at a Very Crisp 90° to control variables.

Tilting the "table" an extra 10° with this mocked up example. Blade is set at 45° (a known known) - therefore the resultant cut will be 35°... more than I need, so I wind/tilt the blade back up the needed 0.75° and.... viola! a cut that is bang-on 35.75°.

Neato. Simple to make, exact too (plus when its trimmed properly I'll have a very neat end for alignment at the blade).

Hope the flow of photos makes sense.....

Any limb-rending near life experiences from this would you think?

p.s. please do excuse my shop cats sleeping on their blankets and domes on the background bench! They love it in here during winter (its pretty bloody brisk tonight!!!)


Showing the current test cuts of 45°...... all good, no burns*, my "riving knife" (i.e. 3mm MDF board) does a fabulous job of ensuring the cutoffs don't touch the blade....

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Setup of the new Sample Sled and getting it to 10° (on the first eyeball guess!.... look at that Wixey!)

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.... and one can see that the cut will be 35°.....

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* except for the one that is, in fact, burnt. That was before I put the "riving knife" on.

Originally Posted by elanjacobs

I wonder if that might make them too fragile? You'd end up with the MDF version of short grain and I don't think the feather edges would survive.

Yeah . May have to leave a little extra for planing off in one of the jigs needed

Originally Posted by elanjacobs

I wish I took a photo of what MDF did to one of our sets of HSS moulder knives; you could clearly see where the board had run, there was close to 0.5mm worn away.

Really . Never seen it . Haven't moulded MDF . Hope I never have to mould MDF. The thought of it has me feeling like something is crawling on my skin around my neck.

Originally Posted by elanjacobs

I think we might be going about this all wrong... Why not just use thicker MDF and have a V-bit made with a 108.5 degree included angle and simply run V grooves on a router table? No cutting, no sticking, just a solid piece ready to be painted.

Sounds good .

Originally Posted by woodPixel

Showing the current test cuts of 45°...... all good, no burns*, my "riving knife" (i.e. 3mm MDF board) does a fabulous job of ensuring the cutoffs don't touch the blade....

Are you out in your shed now P*ssi*g off the cats . Yes its cold .

That looks good . Do they need planing or sanding ?

Something basic like this for holding in vice to plane and sand.

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Auscab, yeah, exactly. That simple jig style is how I get my yosegi zaiku exactly right. I cut with the kataba and finish plane with the kanna. This is how I thought I was going to have to do them..... All....

I think the fake angle table will work. I need to spray in the morning (9degrees all day!), then I'll get to jig making.

Another thought I had is the end is height adjustable One can fine tune the angle

Update in the afternoon.

im staying out of this one, small pieces of timber and table saws are not a good recipe for me............

How is that 3mm MDF 'riving knife' attached wP? I'd love something that moves with the blade tilt instead of the 'feather' in the rear of the zero clearance insert idea.

Fumbler - for sure! Blades and fingers, what could possibly go wrong?

I take a lot of time, far too much, thinking about how to avoid injury. I've bumbled myself twice - once lifting a full sheet of 32mm MDF and another with a lathe accident that put half a heavy bowl into my face.

For the table saw, its as much safety as I can get - mainly from jigs and never putting my hands anywhere near the blade. Everything is held in place remotely via clamps, knobs and hold-downs. Still want a SawStop however ..... too poor


So! Aldav - pictures attached. Its not much, but it works an absolute treat. The original riving knife was a very thick steel affair. It matched none of my blades.

I made up a few of these MDF ones with the template attached. The thickness of each is a hair thinner than the blades. I "tune" the riving knife so if ever-so-gently pushes the offcut to the right of the blade. The tuning is done with four grub screws that wind into the main mount. These can be seen in the second photo. By tweaking these one can adjust the board to the desired angles to deflect the offcut without causing force, torsion or restriction on the cut.

Even the 3mm is quite stiff enough for heavy work. Ive used it for years. It still has the pencil marks on it, so its not "wearing out".

I, personally, believe that it is absolutely superior to the metal riving knife. Its lack of rigidity is its super power. By having the four grub screws wound in such a way to give me the needed deflection, the riving knife acts as a very light spring on the offcut. It just *pops* it to the side. Just a few millimetres, but enough that I've *never* had a catch which has flung a chunk at me.

Also, even if something terrible were to happen and the blade grabs it, then a 3mm chunk of MDF weighing 50 grams is preferential to the steel hand-grenade that the original knife might turn into.... plus my saw blade isn't disintegrating in front of my face

The feather style is still my absolute favourite though. I only use the MDF riving knife for arbitrary non-90-45° cuts.

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These are my feather boards. The rationale for the holes is explained in some other thread here....

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Featherboards?? or TS inserts with a fixed riving knife??