Improving accuracy on cheapo tablesaw

[BrianD]

Hi all,
Out of desperation, I have even made a sled for this cheap tablesaw. I have used perpex as my guide rail (I even mounted 2 rails) under a piece of 6mm MDF and mounted a cross piece of wood on top of that.

I still cannot cut two shoulders accurately (meaning that the two shoulders of a tenon joint will be in alignment).

I am being driven nuts! :evil: :evil: :evil: :evil:

Am I really wasting my time.

I unfortunately cannot afford right now to buy a decent cast iron table saw :evil: :evil:

I am trying to make a breadboard table top and need the shoulders to match.

Maybe I can recur the slot - the table top is aluminium with a 3/4 standard slot? This piece of junk is a Machine Mart cheapo.

Is this possible at all?

Any advice please.

Thanks

 

[Paul Chapman]

If you are trying to cut a very accurate joint on a saw that is not capable of that sort of accuracy, then I wonder if you would be better off trying a different approach? I'm not sure what other tools you have available, but a router might be better, provided you can accurately line up a straight edge on both sides of the board, and possibly fit a large sub-base to the router to provide increased stability and a straight base to run along your straight edge. Or how about trimming the joints with a sharp, finely set shoulder plane?

Hope this is of some help :wink:

Paul

 

[engineer one]

ok so how did you build the sled????

the simplest way to ensure it is as accurate as it can be on the saw you have, is to do the following. make sure you have a piece of wood long
wide enough to go over the slots on either side of the blade.

fit a front piece that is square to the blade, and goes all the way across. it needs to be at least 30 mm higher than the highest point of the blade.
next run the sled through the blade. this gives you a cut square to the blade.

to ensure that the tenons match then, you need a stop at the length of the
shoulders that you want to cut.

personally i would make the sled about 600 deep, and build a rear and a front cross piece and a blade guard between the two .

paul :wink:

 

[Philly]

Brian
Are your components properly prepared? If the sides are not parallel when you flip them over to cut the shoulder on the other side they won't meet up.
I had that problem-took a while to click :roll: If you are using a sled and you have built it accurately you should be able to to use your saw to cut shoulders.
Hope this helps
Philly

 

[devonwoody]

The ends must also be square (tenon piece) or stop block will create an inaccurate cutting line.

Blade must also have little run out.

 

[BrianD]

Thank you all for the input.

It is quite frustrating to say the least.

I felt I had wasted my w/end with this.

I used perpex as my guide with a MDF landing. I battened both ends to ensure stability. So I figured it would be OK - but not so.

Perhaps the existing slot and blade are not parallel? Maybe this is it! :idea:

Although I thought I had checked that out but maybe not properly.

Is it possible to cut a new slot in this table top? (3/4 std slot)

Has anybody done this?

Cheers,
B

 

[LyNx]

why can't you bolt on a larger piece of MDF as a new top. You can then groove a channel to suit for your sled.

 

[engineer one]

brian,
you could always make a new low clearance saw plate. just cut one to size for the overall gap, and then run the saw blade upwards through it. but that will not solve the initial problem.

you need to check the runout, and the parallellness of the blade.

if you don't have too much high tech measuring equipment. try the following. make sure the saw is turned off at the mains fix a piece wood to the mitre gauge, and move it up along side the blade. next adjust so that the wood is about 50mm from the blade. now use a cramp and fix the wood to the mitre gauge. set the mitre gauge at 90 on the scale.
now tape a marker pen to the wood so that it is about 12mm off the
table top. and touches the front of the blade. now rotate the blade and see whether you get a complete circle of ink. this will tell you whether the front is correct. now move the pen to the back, and repeat at a slightly different place. then try and draw some diameter lines across to see whether they all touch the blade properly.

as far as the blade and the slot are concerned. cut a couple of thin sticks and again fix them to the mitre gauge, and then check where they touch the blade. if all this is square, then something else is wrong.

maybe the perspex is not strong enough.


hope this helps
paul :wink:

 

[devonwoody]

To BriandD

The above reply by engineer1 also applies to expensive tablesaws.

 

[Anonymous]

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[Niki]

Hi BrianD

I was using one of those cheap bench saws for almost 10 years.

The cast aluminum table will never be flat and I checked it even on Bosch and Dewalt.
The miter slot is also not something to be admired of.

I improved it by screwing an 18mm plywood plate on top of the original.
I aligned the plate to the blade, made a T fence and aligned it to the blade and then, I made the miter slots with the router while the T fence is acting as a guide.

I made the plate longer (120cm) and wider (60cm) so I could clamp the T fence to the plate from both sides (later I made a better locking system with knobs).

Maybe the pictures will give you some ideas.
Now, that I'm older and wiser (well, at least older), I strongly recommend a blade guard.

Sorry about the pictures quality, they are scanned.

niki

 

[devonwoody]

Niki, those were the days when I had a B & D drill with a circular saw attachment etc. and built three boats. Fixing battens were screwed to the garage floor to hold boat frames and there wouldn't have been room for any of the modern fangled machinery stuff.

 

[Anonymous]

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[twobarrows]

>I remember my first 2 speed orange B&D drill - the finest that (my) money could buy.<

I've still got mine !!! The gearbox is a bit dodgy (there's grease oozing out all over the place) but it is only used for mixing plaster these days!

 

[devonwoody]

You could also fit a dough hook and let the wife use for bread making!

 

[twobarrows]

She's funny about machine grease in her bread, fussy moo.