Table Saw Flatness Tolerance

[Jona]

Hi all,

I recently bought a new Itech 01332 table saw, having read good things about this and the SIP & Axminster variants. Obviously I picked the Itech as it was the cheapest .

The top comes preassembled to the upper part of the cabinet and face-down on the pallet, so the thing was pretty much fully assembled before I turned it over and took off the protective plastic. Putting a 24" straight edge on the top I found it rocked noticeably in a couple of places, and showed light in a couple more- not encouraging. So I got the feeler gauges out and found a maximum deviation of between .25mm and .3mm- ie. the .3mm gauge just about interferes at the lowest point.

I found some posts on US forums and the general consensus is that a tolerance of .01"=.254mm over the entire surface is normal. I'm getting that just over my 24" straight edge, so the total deviation is almost certainly greater than this. Now I've added the extension tables, both of which are much flatter than the main table, and the left one particularly really shows up the distortion; however I set it there is a very noticeable step between the two at one point or other which is pretty annoying.

Now I'm a realist, I know it's a sub-£1000 Chinese saw and not a granite reference slab. I also know I'm working wood, which moves day to day, but I do find this all quite irritating from a brand new machine. The options as I see it are:

- Just live with it
- Try to send it back
- Sell it and buy something better
- Try to level the table myself by hand

Do any of you have this issue with your Sip/Axi/Itech saws? What would you do? Sorry for the long post.

Jona

 

[flh801978]

Depending on where it is I would live with 10 thou out
However a step between the tables I would have to sort out

Ian

 

[Wizard9999]

I fear from your post that now you know it is there it is going to bug you forever. Have you spoken to the folk where you bought it to see if they think it is reasonable / acceptable / normal?

Terry.

 

[MattRoberts]

I've never really checked if I'm honest. The question you need to ask is whether any discrepancies in the flatness of the top will impact the accuracy of your work.

I'd argue that a third of a millimeter is not going to cause inaccuracies that you're ever going to notice

 

[Jona]

I have not yet contacted Scott & Sargeant, I wanted to gauge opinion here before getting shirty. Based on other forum discussions I fear that they would argue that it is within tolerance, and with some justification. It does occur to me that had I opted for the slightly more expensive Axminster version, their customer service reputation is such that I'd have a much better chance at arguing the toss.

I agree that it's unlikely that ~.3mm will cause me major problems in accuracy or safety, but it is still disappointing. It's the step between the two tables which is most annoying as it's very easy to see and feel. As the table edge describes a gentle 'S' curve, it can only be level in two places; elsewhere it is either high or low.

Thank you for the input.

 

[dzj]

I agree with what MattRoberts says.
Make a few test cuts, check the angles, check for consistancy, quality...if all is well, who cares about slight deviations.

 

[Lons]

I doubt it will make any difference, the wood can move that much when you relieve the stresses cutting it. The step is another matter, my Sip was similar though hardly noticeable and I lived ith it for a few years before taking a sanding block and going though the grades to get rid of it. i only did that because some silly person ( 0 put a coffee cup on the table and a rust stain appeared requiring steel wool and wax treatment.

Bob

 

[Steve Maskery]

I'd say that that was within acceptable tolerance. As you say, it's not a surface plate. As long as it is reasonably flat in the area around the throat plate, then I think the rest is academic.
There are far bigger concerns about alignment than this. For example, it is much more important that you can get the blade, rip fence and mitre slot all in alignment. I wouldn't live with 0.3mm there. But on overall flatness, I would say that it was acceptable.

Sorry, I guess that is not what you wanted to hear.

S

 

[RobinBHM]

The problem with cast iron is that it can warp. I think some manufacturers used to allow allow castings to season, but I cant imagine that happens with a Chinese machine.

Also it is possible that the warp could have been caused when it was bolt to the body.

If the saw blade area is a high spot, then in some ways that can be a bonus to a dead flat top.

I certainly wouldnt be disappointed yet, get it set and see how it works in practice.

Even much more expensive machines may not have dead flat tables.

 

[Jona]

These comments broadly confirm my thoughts. Most likely I'll set it up as well as I can as-is and get some proper use out of it to see if any genuine problems emerge, or indeed if the step continues to bother me. If so I'll have a go at sanding the whole top with a good flat plate.

Cheers

 

[Lons]

These comments broadly confirm my thoughts. Most likely I'll set it up as well as I can as-is and get some proper use out of it to see if any genuine problems emerge, or indeed if the step continues to bother me. If so I'll have a go at sanding the whole top with a good flat plate.

Cheers

Before you start down the abrasive route you should be aware that it's bloody hard slow work

 

[MattRoberts]

Indeed, but given your dealing with 0.3mm, even taking 0.1mm off will help

 

[Jona]

These comments broadly confirm my thoughts. Most likely I'll set it up as well as I can as-is and get some proper use out of it to see if any genuine problems emerge, or indeed if the step continues to bother me. If so I'll have a go at sanding the whole top with a good flat plate.

Cheers

Before you start down the abrasive route you should be aware that it's bloody hard slow work

I bet it is! And of course, once I've ground down the high spots with coarse abrasive, I'd need to refinish the whole top to a consistent grade. I'd expect a hard day's work, with plenty of swearing thrown in. On the plus side, I could get rid of all the machining marks and end up with a lovely flat, polished surface.

Out of interest, does anyone know what the going rate is for having this done professionally? I'm guessing they use a massive wide belt sander.

 

[MikeJhn]

Not a belt sander, think warped cylinder heads.

Mike

 

[Jona]

Something like this?

https://www.youtube.com/watch?v=qBmMWHJZc50

 

[lurker]

This might be talking bullocks, but I think I'd slacken all the bolts afixing the table, leave it a while, say over 24 hours. Then nick up (but not mega tight) the nuts in a sequence like you would when putting a cylinder head back.

 

[Jona]

I can see what you're getting at; could definitely be worth a shot letting it do its thing without restraint. Certainly won't do any harm anyway, before getting drastic with the sandpaper. Also handy that it's Friday so I can leave it all weekend...

 

[MusicMan]

You will find it a very hard job with sandpaper, not only physically but in getting enough accuracy. I'd allow about two weeks rather than a long day.

The way to level cast iron machines is by hand scraping. Thousands of internet threads/videos on this. Still slow and hard but maybe a couple of days. You need a straight edge and preferably a surface reference plate.

Commercially it would be done by a big surface grinder. Birmingham Machine Tools is an example of a company that does this, with a grinder that can handle about 3 metres wide! I had an old lathe reground on 5 surfaces by them, very well indeed. It might cost you more than the saw did. And as has been said, if the iron has not been properly stress-relieved it could easily warp again.

I think I have that much dip in my old a superb Wadkin. Doesn't affect anything, and I am fussy about accuracy and calibration. (In my day job I once designed and built a machine, for NPL, to measure small displacements to 10 picometres).

Keith

 

[bugbear]

...to measure small displacements to 10 picometres.

https://en.wikipedia.org/wiki/Picometre

:shock: :shock: :shock:
:shock: :shock: :shock:
:shock: :shock: :shock:

BugBear

 

[Jona]

I've taken off the fence rails and extension tables, and loosened the table mounting bolts, now it will sit in my workshop until Monday morning when I'll check if it has moved at all. I'm not expecting much to happen but it's relatively little effort; and who knows how long it's been sat fully locked to the chassis since it came off the line?

Thanks again for all advice.