Riving Knife Alignment

[Mark A]

Hi

I've almost finished setting up my Axminster TS 200 table saw now but inevitably the last thing I've got to do is proving to be difficult. The riving knife is way out of alignment (skewed 3/16" front to back) and is also a bit bent. I haven't used the saw yet because I wanted to get everything set up right first so I don't know if I should phone Axminster and ask for a replacement riving knife, or are there ways I can fix it myself? I can shim it square to the blade but I don't want to attempt bending it back into shape if I can get a replacement.

It's a nice little saw but it's a right turnip to set up! I didn't know that bolts could be made from plasticine :lol:

Thanks

 

[Steve Maskery]

Hi Mark
That sounds rather serious. A RK should be flat. If it is not, then the chances are that you will snag it as the timber goes past the blade and encounters it. The last thing yo want is to be manipulating the workpiece to negotiate the RK. It should be seamless.
What is the RK made of? If it is just mild steel then, once it is bent, there is no chance of getting it properly flat again. Tool steel (flat ground stock) is a much better material. It's well worth an hour with a hacksaw and some files.
Sounds like you know just what it should be like, and that's half the battle.
S

 

[Mark A]

Thanks for that Steve

Actually, I don't have much of a clue about it! I've never used or set up a table saw before so this is new to me. I've been reading a lot of posts about it though and watching videos on youtube (including your's - kudos for that!)

It's only a £200 saw so it'll probably be mild steel. I'll phone Axminster tomorrow and see what they can do. They've already sent me a replacement part (blade washer) so I think it was assembled with a TGI Friday feeling!

 

[Furtree]

Hi Mark,

Assuming it's made of m/steel, I was just going to suggest taking it off and straightening it out on an 'impromptu anvil' (an old piece of RSJ girder, or off-cut / block of other nice, flat steel, using a lump hammer or some such?) ... But then Steve M. got in before me, and said what he did about m/steel... Maybe he's a better engineer than me (-quite likely, as my ol' dad was more a woodworker than a metalworker!)

Maybe work this both ways? eg: Phone Axminster, and tell 'em you need a new one, if they agree (quite likely!) then you can (literally!) 'have a bash' and see if you can sort it yourself, whilst you wait for the new one to turn up.
= If it works, you end up with a spare!

If not, well, -- you just learnt a bit more about engineering ! :?

Nb: Back in the day, when I wuz a lad, (about 10 or 11yrs) onwards, I used to run my dad's little homemade circ saw bench without any guard, let alone an RK, (and totally unsupervised too!) --- but best not tell the H&S folks about that, they'd go ballistic!
(And yes, I have still got all 10 fingers fully attached!)

Having said that, I never tried cutting any parana pine on that saw bench, which is certainly one occasion when an RK is *very* handy! --> for those who aren't intimate with P.-pine, it has this trick of going like a pair of crossed fingers as you rip it down.
By the time you've got halfway down a 3M length, the two parts you've just sawn through are likely to have crossed themselves over completely!
_______________

Tech note: "parana pine" is NO relation to those little fishes which wanted to eat James Bond(?) alive, way back when. ~ They're called Piranhas , and though they float, they aren't made of wood!

--tee hee!

 

[Mark A]

Thanks for that

Unfortunately I don't think I've got any big flat lumps of metal anywhere. I usually use the side of a sledgehammer head as an improvised anvil but it's a bit too covered in cement for peening my riving knife!

I'll phone Axminster tomorrow and see what they can do. Hopefully they can replace it because I'm having a nice little break from engineering (read Health and Safety) at the moment as I've just finished my BTEC national diploma in engineering.

Using homemade tools unsupervised? When I was a kid I set myself on fire trying to make a potato gun from some 63mm pvc pipe and lighter fuel #-oWorked ok actually. Then I made napalm... I think HSWA, COSHH, RIDDOR and DSEAR regulations where breached (to name a few!), and I didn't carry out a risk assessment before hand. How I love H&S!

Mark

 

[Lord Kitchener]

In my experience riving knives, if they need it, are easier to bend than to bash. What you need is a way of holding the bottom end while you bend the top as required. Also, many RKs have a narrower leading edge, if your's doesn't try grinding one on so that it self aligns as long as it's not too far out (1/2mm or so)

 

[Mark A]

I phoned Axminster this morning and they're going to send me a new one. I'll try fixing it but when I put it down flat on my workbench the top edge is nearly 1/4" off the table, and quite twisted as well. It might not be beyond repair, but I think it is beyond my ability!

Mark

 

[Digit]

It might not be beyond repair,

Unless less you are long dead jewish carpenter it is!

Roy.

 

[Steve Maskery]

It might not be beyond repair,

Unless less you are long dead jewish carpenter it is!

Roy.

LOL I rather agree. You'll never get that properly flat, don't wast your time. Buy a piece of FGS and spend a satisfying hour in your workshop. I say "satisfying', I mean, "hard sweaty work that I don't want to repeat in a hurry." But the end result is satisfying. And if you can wait a month or two, I have the video footage to prove it. Finding a new address is, sadly, more of a priority at the moment.

S

 

[Mark A]

Hi Steve

I should receive the replacement riving knife either today or tomorrow so I'll make do with that for now. I'm looking forward to seeing your video though

Thanks
Mark

 

[Mark A]

Replacement arrived this morning... and it's bent as well. Only somewhere between an 1/8" to 1/16" so I guess this is fixable? If it is, then should I clamp it down and bend it or hit it with hammers until flat?

Also I found out today that the cast iron top of the table saw is not perfectly flat. How much light visible under a straight-edge is acceptable? It's only about 1/32" (sorry I think in old money) but it's around the opening for the blade where it dips the most.

Thanks,
Mark

 

[Steve Maskery]

I refer the honourable gentleman to my previous answer!

As for the flatness, I wouldn't expect much better on a saw in that price bracket, to be honest. If it's any consolation, we all buy a cheap one to start with and upgrade when we realise the significance of its shortcomings. Well, I did, anyway.
S

 

[Mark A]

Thanks Steve

I refer the honourable gentleman to my previous answer!

Of corse! Sorry, I forgot to look back at what was said #-o I'll have a go today.

To be honest I wasn't expecting much for 200 quid. It's just my lack of space which forced me to get this, because my 8x10 shed is shared with the lawnmower, an outboard, 2 bikes and some sapele I'm going to sell.

Mark