Cheap DADO Stack That Works and Is 'realitively' Safe for a Cheap Table Saw

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Introduction: Cheap DADO Stack That Works and Is 'realitively' Safe for a Cheap Table Saw

About: Working on motorcycle since age 11 Instructor at MMI from 2000 until mid 2011. Started in a Honda/Yamaha/(old) Triumph twin dealers, moved to Suzuki/BMW/Vespa dealers in 1980

Christmas 2016 I got a cheap 'contractor' bench saw from HF Tools.

I do very little 'wood butchering of dead tree carcase' (hesitate to call it carpentry) but I kinda enjoy playing with machinery and making 'stuff'

HF saw works more than well enough for the stuff I do but no way would I buy a Dado blade/stack costing more than the saw.

I've seen multiple posts on various sites asking or showing how to make a dado stack. There is a LOT of criticism from 'real' woodworkers (professional and hobbyist) about how unsafe a stack of carbide tipped saw blades are.

The main issues seem to be blade slippage and teeth chipping throwing carbide 'bullets' around.

There is a very simple and cheap way to help prevent this using ordinary cardboard, I used the separators from the cat-food we use but almost any relatively thin (1mm/0.040") non-glossy card can be used. Use only 'solid' card and not corrugated packaging. As always, do this at your own risk

Step 1: Choose Your Blades

First step is to realise this could be dangerous

You will need blades about 2" smaller diameter than the rated size for saw, the torque applied to smaller diameter blade of greater 'width' than stock should balance out motor power somewhat?

I got a five 8-1/4" diameter from eBay for about $4.95 each with free shipping to replace the 10" standard blade, total cost under $25.00 so made 'experimenting' a viable option. A lower tooth count would be better but these were the absolute cheapest I could find at the time, will look into getting a few sub 30 tooth and use 40 on outside edges only

Probably should have taken some measurements of spindle length before ordering as HF saw has a 'short' spindle, looks like 5/8" will be max width with blades straight up and down using all 5 blades?

Step 2: Card Washers -the 'safe' Drive Method

This is important, VERY, VERY IMPORTANT.

You will need a lot of card washers, I cut mine about 3" diameter with a pretty accurate 5/8" centre hole.

Centre hole needs to hold washer in place without being too far off centre and not have any 'tags' that could prevent full contact with saw blade. The fibers of card will compress very little plus the surfaces tend to interlock with each other and the ground face of saw blade. for fine adjustments you can use paper washers (as long as it's not glossy or waxed paper)

This is something I learned when training as precision machinist in mid 1970's, the amount of pressure paper and card can take without damage is pretty extraordinary, several tons more than '2hp' saw motor can provide even with the inertia of 3,000rpm blades

Do not use any type of plastic as it WILL slip.

Rubber is too compressible if your using re-cycled inner-tubes so DON'T

Step 3: Practice Setup and Blade Storage

When blades arrive.................

Simpler to assemble on a 5/8" bolt to make sure things will sit flat than mess around down slot of table saw plus you get a better idea of the width your going to cut

You can also check how much clearance you have between blade teeth for various set-ups and 'step' teeth for cutting clearances. Using a 'full blade' instead of chippers a dado stack comes with gives a much more 'gentle' cut requiring less power and a load less vibration than an angled cutting blade

If you have a long enough saw spindle, you can mount steel washers of varying thickness BETWEEN card washers to extend range/width, the picture is blade, card washer, steel washer, card washer blade sequence using all 5 blades to get about 1-3/8" cut width

I did this step before checking saw so will be making a few 'angled' washers to get wider cuts or a 'tube nut' and grind out blade holes to a larger diameter as I would like to be able to cut at least 1" wide. (no idea on blade centre hardness,being carbide tooth on steel blade it may be possible to drill them?)

3" long 5/8" nut and bolt also makes a simple storage 'device' to keep all the parts together

Step 4: Taking Things Apart

First, unplug machine to make sure it isn't possible for anyone to start it (I once had a boss destroy a bunch of expensive stuff by 'helping' while I was at lunch)

Remove insert/cover, unscrew the nut holding blade and remove original blade and drive washers. There are flats on the shaft which flats on washers align with, 'conventional 'right hand thread' which automatically tightens when running

I forgot to take any pictures, sure it's in 'blade change' instructions that came with saw?

Picture of 10" and 8-1/4" together for comparison

Step 5: Set Up 'stack' and Test Cuts

Add blades then card washers to get width you want,(or as much as you can get with simple set up)

I set up for 1/2" wide cut which surprisingly actually cut 1/2" wide slot.

I did not use the 'inside' washer but did use original pressure/drive washer under nut

Although I wasn't intending to actually make anything I got some short pieces
of old 2x4 pallet from outside garage. Damp and distorted but great for 'experimenting'

Didn't do any real measuring and guessed width/depth but decided to 'refine' things after making first cuts.

I never noticed knot until flipping piece over, 1/2" wide, 5/8" deep, not even a slight problem, almost zero vibration and quieter than a 'real' dado blade plus only took 5~6 mins to cut two 4"wide slots in 4x2's including 'set up' time

Step 6: Conclusions?

Worked way better than expected, very fast even though not as wide as I wanted.

Couldn't use steel washers because spindle is too short

There is a bolt at front bottom of spindle which rubbed on blade very slightly, (see pic of 'witness mark' polishing side of blade)

I'm not sure if it helped stabilise stack?

Fitting a thin washer before first blade will be next experiment, there are enough threads for it not to be a problem

Friction was minimal, I didn't notice until after doing the various cuts

Overall a good result and I will be using this for more accurate work

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8 Comments

I use a similar set up almost every day, I have a woodworking shop with multiple table saws. One is dedicated to making a 3/8 wide 1/4 inch deep dado in some molds I sell online. I bought the cheapest blades Home Depot and have not bothered to put any sort of spacers between blades. This saw is powered by a 3 horse motor and makes a sanded smooth dado cut. PS I own two dado sets I keep sharpened to make raised panels but I think the homemade version does as good a job if not better. I have used these for six or seven years without incident....so go figure.

This is an interesting trick - I don't have a table saw, but I will keep it in mind for the future if I ever get one. Last time I used one was back in high school 25+ years ago (and we had a proper dado blade set, too).

You mentioned that using washers wasn't possible due to thickness. Today I was looking up "shim washers" and managed to find some from "small parts" - but they weren't very large, and probably wouldn't work for this purpose. But they were very thin (0.001" and larger). I was looking into them for bevel gear location purposes (to shim bevel gears properly for meshing).

But maybe you might be able to find larger ones? Or, maybe you could get a sheet metal shop to make some from some thin steel sheet? Though it might be cheaper at that point to buy a dado blade set...lol.

Thanks for the instructable - it was fun to read and informative, too!

This week a lot of synchrony happening. I just did this yesterday to slot 2x4s for glazing on garage OH doors passive solar panels. I did not insert card stock between the blades, only 3/8" slot needed. Instructable on the panels was posted a few days ago. The same day I started my project. Too wired.
Anyway, it worked great. Slots were dead center and done in one pass.
Jim

1 reply

Yep, when an idea's time has come it will happen. It's not the first time I've heard this, about 25~30 yrs ago I 'invented' a 'pulley' to reduce friction on bicycle dérailleur gear change, less than a month later a 'commercial' version was being previewed in cycling magazines. Wasn't as 'good' as mine tough as it was only available in a 90 degree 'bend'
I made various angles as POC but 90 and 120 were the only ones I used. They worked really well (and still do when cleaned and lubed) but as there was already something on the market I never went any further with idea

Cable pulley 1.JPGCable pulley 2.JPGCable pulley 3.JPG
user

Have the SAME HF table saw. I will def try this!

1 reply
user

...also: Nice job!

Hi crazypj,,I also have a cheap ts & have been wondering about using stacked blades like you have here.You have answered all the questions that I was going to ask so thank you for this great instructable.,