Acceptable table saw blade runout?

[gidon]

This is something that has confused me for a while. When lining up saw blade with mitre slots or sliding table - it's usually recommended to use one tooth on the blade as a reference. This I've been told is because the blade doesn't run true until spinning at high speed.

But I was trying to get my sliding table cuts more accurate (a job on the to-do list for nearly a year!) on my Scheppach TS2000 and this advice was puzzling me! As was the advice from Scheppach to set the sliding table against a straight edge pushed against the inside (left-hand) side of the blade. Which will give slightly different setup results again.

I decided to measure the runout (if this is the correct word) of the blade at hand rotation speed - to see if it varied with blade. Result: not much variation across blade - all blades were out by about 0.2-0.3mm. Also measure the arbor runout and that was undetectable ((<0.05mm) so that was reassuring.

So after all this rambling - I was after some pearls of wisdom on the subject. How much time do you spend setting up your tools? When are they good enough? I did some crosscut tests with diifferent blades. With a couple hours of set-up a cross-cut (with sliding table) from a 64T Freud industrial blade was close to perfect. But a straight edge across the cut and held up to the light did still reveal some very slight light coming through. Am I being too fussy? Do you think this is the blade or the set-up. Is the some play in the sliding table I haven't noticed?

If you're not completely bored now I would appreciate your comments!

Cheers

Gidon

 

[Philly]

Hi Gidon,
Yes, it really is frustrating setting up the sliding table. I have a Record RSTS12 which has had me pulling out my hair :? I dont know how it goes with your saw but on the Record, there are 4 roller bearing which the table rides on. These also adjust the table height, relative to the main table. I would set the table parallel to the blade, lock it off, test, be happy and then notice the sliding table wasn't level with the table. Adjust the height then find it out of true with the blade again. GRRRRR :twisted:
I have tried various means of getting the table parallel with the blade, most you have probably tried. I still got the same result as you-not a perfectly true cut. Always a tiny bit of light showing thru past the straight edge. After much investigation I have found this-the motor/trunnion is mounted into a steel box/frame. This "gives" a slight amount under force, and I am sure this is to blame for the slight inaccuracies. My saw is not a Pro saw-it's a diy/hobbist tool. I think you have to be happy with the results you get from this kind of tool to do a bit of hand work to get to perfection, or as Kevin Ley said in his recent articles on choosing equipment, "get 80% of the result for 20% of the outlay".
Personally, I am saving up to buy an Excaliber Unisaw clone. That should give me the performance I am looking for.
Hope my ramblings have been of some help,
Regards,
Philly

 

[Chris Knight]

Gidon,

I think it is well worthwhile taking time to set up a saw to cut square - the frustration that follows if cuts are not square, discovered maybe only when putting a structure together, is just too horrible!

When I had my TS2000, I was always having the sliding table (and the beam along which it runs) off and on in order to free up room in my workshop for some operation or another. I found that I usually managed to disturb my careful setup in this way and so developed a habit of making a test cut on a piece of hardboard about 18 inches square (taking a sliver about 1/4 inch wide of one side) and checking it for square. I then used the adjustable mitre gauge to compensate for any out of squareness. I found that with practice, I could do this very quickly ( I had learnt how much the mitre gauge needed adusting so that I could make a single adjustment and be spot on). It was not an ideal arrangement but after a while it became second nature and ceased to bother me.

 

[Anonymous]

Gidon

Time well spent. I set my tablesaw fence etc. against two teeth, one at front of table and one at rear without spinning the blade. I also ensure that the DTI is on the cutting tip of the tool.
Acceptable run out? None!

I spoke with a guy recently who sharpens blades and he says that lots of 'off the shelf' blades (Freud, Trend etc.) cannot be retentioned properly and thus you will always get runout when rotating.

I do not think that you are being too fussy, I spent 1/2 a day setting my tablesaw and sliding carriage up and now I trust it for every cut and steup

Cheers

Tony

 

[johnjin]

Hi Gidon
It sounds to me like you are being a bit over fussy. I agree that it is essential that the saw cuts straight and square, but to what degree are we talking about.

But a straight edge across the cut and held up to the light did still reveal some very slight light coming through.
You would be able to see .001" under those circumstances and I can assure you that you will never better that on any wood cutting saw. So what I am trying to say here is that maybe you are being a little fussy and worrying for nothing. If the work that you are doing is coming out to your satisfaction thats good enough. If you want to know just how much it is out, put a feeler gauge under the straight edge and then you will have a proper measurement.

All the best

John

 

[johnjin]

Whoops
Sorry about that I forgot to end the Quote.

John

 

[johnelliott]

I run an Electra Bekum PKF255 so I also have issues with sliding tables. The sliding table on mine has a traverse of about 1.4 metres, and I often use it to straighten pieces of stock, hardwood or sheet material. I know that all the equipment is this sort of semi-pro orice range tends to be somewhat less than perfectly rigid, so things such as how hard one pushes, and the steadiness of the traverse speed all have an effect on the results obtained.
When setting up one can get to a point where all the adjustments possible are made, one tightens up and something goes out!
The more you have to undo things to change blades etc, the more often you are reminded of this. It's absolutely necessary to have some kiind of personal standard to adopt, or you would never get any woodwork done. I find that as long as the blade cuts vertically, and that the crosscut fence is square then a very slight run out along the length of the cut probably won't matter too much, it just depends on what you're doing.
In the end, it all comes down to the quality of the tools one is using, and if you, like I, can't afford an Altendorf (yet) then we just have to do the best we can, and strike a balance between time setting machines and time using them.
John

 

[Philly]

Hey All,
A extra little thought- I bought a Jet cast iron surface planer last year. The thing impressed the hell out of me-the surfaces are solid and immovable, the fence vast and solid. It is happy with small pieces of stock or great big slabs. Because it is built to a high (relatively) spec it does it's job impecably. It still performs to the same standard regardless of how hard you push on it. This is why I have a growing love/hate relationship with the ally/pressed steel things on the market in the U.K. Cast iron tools used to be the norm (no pun intended ) before the days of ally extrusions. We should be able to expect the performance we require from the tools we buy. After all, how much are the table saws we are talking about here? a £1000? Thats a fair old wedge of cash. In my opinion, the machines in the semi-pro market at the moment are sold on the amount of features that they offer-not the precision. (although thats not what the marketing bumph will say.....)
regards, (rantingly)
Philly

 

[gidon]

Thanks for the helpful replies.

Philly - setting up tools is a time consuming task I agree. I must have spent a good day on my planer thicknesser - but it was worth it. I don't think everything has to be cast iron. I would have trouble get cast iron stuff into my work shop for a start! But I agree some of these alu extrusions are a little dodgy. The steel on the planer thicknesser is fine though - no complaints there. Thanks for the tips.

Chris - it's not so much the square that I'm having trouble with - it's the straightness of cut. But the test cut idea is probably a good way to tackle it - thanks.

Tony - when you say aceptable run out is none - are we referring to the same thing? Ie - measure most extreme tooth, spin blade until gap between measuring device and tooth is furthest. Do you really get no runout at all on your machine? Or are you referring to when the blade spins at full speed - I've heard it balances itself? Interesting about the off the shelf blades. Does this mean we have to get our blades custom made :lol:.

Johnjn - you could be right! But as Philly said here we're not talking about cheap kit so I would like to get it as good as I can.

John E - agree entirely - trouble is I change my personal standards to fit the current project (and weather conditions) :lol:.

Thanks everyone - some more playing tonight!

Cheers

Gidon

 

[Anonymous]

Thanks for the helpful replies.


Tony - when you say aceptable run out is none - are we referring to the same thing? Ie - measure most extreme tooth, spin blade until gap between measuring device and tooth is furthest. Do you really get no runout at all on your machine? Or are you referring to when the blade spins at full speed - I've heard it balances itself? Interesting about the off the shelf blades. Does this mean we have to get our blades custom made :lol:.

Gidon

Gidon

I have been a design engineer for over 20 years and abhor shoddy work/engineering/design.
I mean that machines should be made accurately and we as consumers should not accept shoddy design nor workmanship in recognised manufacturers products.

I have used two approaches for set-up, one using the same tooth fore and aft (marked with a felt pen), the other to keep blade stationary. I usually accept about 0.1-0.2mm difference on fence alignment across the blade - but none is fine by me

Interesting comment you made about custom made blades. I bought a 60 tooth triple cut blade form the company mentioned above - an engineering company, not a retailer/reseller. This blade can be resharpened AND retensioned and so is a fine investment at £38. Also it cuts veneered boards without breakout.

Cheers

Tony

 

[Chris Knight]

Gidon,

Don't forget blade vibration as a source of non-straighteness. If the blade vibrates it cuts a wider kerf at that moment than if it is not vibrating. This can be seen at its extreme if you use a lousy blade on thinnish ply which resonates in sync with the blade or by stopping and restarting the saw in mid cut.

You can minimise this by a) using a good blade and b) by maintaining a constant feed rate. A practice cut will usually reveal at which feed rate the blade vibrates the most, so just stay away from this rate and feed faster or slower.

When resharpening the blade, try and use a saw sharpener who can retension the blade.

 

[Alf]

I mean that machines should be made accurately and we as consumers should not accept shoddy design nor workmanship in recognised manufacturers products.

'Scuse me while I laugh in a hollow manner. :roll: Where is this small village of yours, Tony? In the Midlands of the planet Zarg? :lol:

Cheers, Alf

Who once thought like that, but the forge of bitter experience has tempered her expectations more than somewhat.

 

[Midnight]

Who once thought like that, but the forge of bitter experience has tempered her expectations more than somewhat.

call me a cantankerous auld fart......but I don't accept shoddy work from myself either professionally or with woodworking... damned if I can figure why I should accept it from others AND pay for the privilage..

 

[Adam]

So after all this rambling - I was after some pearls of wisdom on the subject. How much time do you spend setting up your tools?

None. I've never adjusted my Woodrat, nor my Scheppach TS2500, nor any planes. I use everything exactly as it arrives. I haven't got time to be 'tuning' stuff, I want to get on making stuff. In the time you spend fiddling around with a table saw - squaring horizontally and vertically, worrying about it, building jigs to hold dial-guages square to check things checking the arbour, the blade........ you could have started and finished a proper project, including a few extra strokes of the plane to remove the nats-cock's worth of error off the saw. Honestly, I can't be doing with all this preparing your tools stuff. I like woodworking not fettling. I have never noticed my tools causing my projects to be below standard, it's always me thats the cause of the problem. .So... why worry. Just get on with a few TUITs.

Adam

 

[johnelliott]

call me a cantankerous auld fart......but I don't accept shoddy work from myself either professionally or with woodworking... damned if I can figure why I should accept it from others AND pay for the privilage..

The real question here has got to be...how much is one paying? Perfection costs a lot more than OK, and the prices are mostly set for OK. Living with OK is what most of us, certainly Alf, me too, have to do
John

 

[Anonymous]

Alf, not Zarg but cloud cuckoo land where the companies and engineers care about their products

I stand by my belief that poor workmanship/design is not acceptable see here for an example of what can be done if we all take this view

https://www.ukworkshop.co.uk/forums/view ... ght=#11429

Which surprisingly had no replies (well, I thought it was a good post anyway!)

The Ryobi turned out to be fantastic and the Freud perfect. Could have put up with poorly manufactured kit but chose not to.

My advice is to buy locally when you can - it is always useful to be able to complain to someones face rather than down the phone whe nyou realise you've bought a piece of junk :twisted:



Cheers

Tony

 

[Signal]

Tony,

while I agree with you to an extent you cant always blame the engineers.

I used to be in the electronics industry, used to design telephones/faxes stuff like that.

I would go through the torture of getting the products through BABT approval and once the green spot was issued the product which actually left the factory hardly resembled the product I'd designed. T

The manufacturers where very skilled at removing all those little "Unnecessary" components in a bid to increase profit.

Upshot was a shoddy product which very rarely worked well and would certainly not pass BABT approval.

Gave it all up in the end as I got sick of seeing my designs butchered for the sake of saving a few cents here or there.

Signal

 

[johnelliott]

It does seem as if some of the contributors to this thread don't have a very good grasp of economic realities.
Yes, it would be great if manufacturers were to produce only top quality tools, and if we were all able to afford the prices that would then be necessary. Until that day comes, the rest of us will have to use tools that are less than perfect, purchased from budgets that are less than limitless.

John

 

[Philly]

John,
I hear what your saying BUT-if you spend £59 on a table saw you know just what you are getting. rubbish. If you spend £1000 on a table saw you would expect that to be vastly superior. Is it too much to ask that tools do what they are supposed to do?
I appreciate that most peoples budgets are tight (I know mine is) but it is not too much to expect products to perform they way they are marketed.
regards,
Philly

 

[Anonymous]

It does seem as if some of the contributors to this thread don't have a very good grasp of economic realities.
.

John

Really? I see your point for cheap chinese imports. However I worked as a design engineer and then senior engineer for 20 years before giving it up to teach and thus am fully aware of the realities of economics BUT this is not an excuse for shoddy workmanship, lack of quality control or poor design/materials.
I have seen mitre slots with in excess of 0.5mm gap between slot and bar!! :evil:

Do these companies not know of Lean Manufacture, Six Sigma, Agile Production and Business Process Re-Engineering?
All are well known quality systems that ensure good quality products leave the door at competitive prices.

Well designed and manufactured products do not have to cost the earth and companies can, and do make a decent profit whilst charging a realistic price.
I am clearly NOT talking about these chinese etc. imports as they don't give a toss about the consumer.

I repeat that we the consumer do not have to put up with this rubbish. Use your wallet to demonstrate that poor quality is just not good enough. Take any unsatisfactory kit back - don't be fobbed off with sloppy goods.

Tony