Startrite TS - bad rip cut (now with lots of piccies ;D)

[CroppyBoy1798]

Hi,

Ok so I more or less have my Startrite TA275 sorted. Recieved a set of new belts last week to replace the badly worn and misshapen old ones (the belts were the wrong size to start with and the pulleys were badly out of allingment), so, she's singing sweetly and has lost the bad shudders it used to have.

Next problem, I'm noticing when doing rip cuts that I'm not getting a nice perfectly straight edge, at least not that I'm happy with! The resulting cut is almost 'wavy' ie ups and downs (its not in your face noticable, but when placed again a straight edge and held to the light its pretty clear to see). The results have been the same on both mdf and pine lam board. I'm using a good 10" Freud blade and have used a 12" DeWalt blade also, with the same outcome.

Any idea of what might be causing this and how to rectify it because its really bugging me, I want it cutting straight as a die, as it is its just not up to scratch!! :|

 

[Benchwayze]

Hi Croppy,

I am no machine expert, but I have had similar problems on my old Coronet attachment saw.

So, Have you checked that when the blade is at 90 deg to the table, it is truly parallel to the rip fence and the rip fence is truly parallel with the mitre guide slot. (The last point is important when cross cutting only.)

My saw has cupped washers that clamp the saw tight.I had a problem with those once. If you have these and they are warped, it could cause wobble. You should be able to detect wobble by looking at the revolving saw, edge on. Especially as it slows after being switched off.

Just check also that the blade isn't slightly warped. All these things can have an effect on a saw. If the saw has been 'shuddering', is the arbor still true?
I hope so. Not to scare you but that could be an expensive repair.

HTH

John

 

[newt]

Assuming you are using the rip fence, what is the rough measurement between the peaks of the wavy edge ?

 

[CroppyBoy1798]

Cheers for the help guys!

Benchwayze there is a slight wobble in the blade, this is noticable when the blade is turned by hand, but no more wobble than was in my Makita saw that cut fine. I put a dial guage on a 12" blade and I was only reading a wobble of .04mm at its worst, I believe I read somewhere that up to .012" is acceptable and no table saw will be perfectly wobble free? Obviously the wobble was less aparent on a 10" blade and I was only reading .02/3mm.

The arbour/shaft wasnt reading any significant reading, if any at all with the dial guage and is good and solid when the belts are slackened off.

Newt, bear with me now, I took some measurements :mrgreen:

Ok, so a piece of 18mm plain mdf, 42" long.

One end reads 104.29mm, the other 104.25mm (nothing wrong with that! :wink: )
Some of the 'lows' along the cut measure 103.97, 103.88, 103.77.

A lenght of pine lam-board 5ft long

One end reads 82.59mm the other 82.52mm (again, not going to fault that!!)
The lowest dips measure 82.08mm and 82.06mm.

Ok, it looks as if I'm being pedantic worrying about what would appear to be minute meausurements, but theyre enough to not give a good true cut and allow chinks of light through and thus have to have a plane ran over them to true them up (ok, I expect to have to run a plane over edges at times to remove saw marks, but not to remove peaks and troughs).

Am I expecting too much of my saw, is a true, perfect cut off a table saw a reality?

 

[Hudson Carpentry]

Perfect no. But perfect to the eye yes. Im not familar with the saw you have but I do know I get perfect to the eye (no light coming through peaks and valleys etc) with my own TS and others.

 

[Benchwayze]

Well I suppose most rip-sawn edges get worked on by planes afterwards anyhow... :wink: When I rip, I always allow enough for dimensioning on the planer, and the most accuracy I want next is in cross-cutting. For 'rough' work, I can use the pieces direct from the saw, for jointing.

I don't use a shooting board, (except for drawer and small box making maybe). Dovetailing from the saw is perfectly feasible, as long as I know my saw cuts clean and true. Which it does, because I have a good blade and I set-it up every six weeks or so!

Regards
John
(hammer)

 

[newt]

Cheers for the help guys!

Benchwayze there is a slight wobble in the blade, this is noticable when the blade is turned by hand, but no more wobble than was in my Makita saw that cut fine. I put a dial guage on a 12" blade and I was only reading a wobble of .04mm at its worst, I believe I read somewhere that up to .012" is acceptable and no table saw will be perfectly wobble free? Obviously the wobble was less aparent on a 10" blade and I was only reading .02/3mm.

The arbour/shaft wasnt reading any significant reading, if any at all with the dial guage and is good and solid when the belts are slackened off.

Newt, bear with me now, I took some measurements :mrgreen:

Ok, so a piece of 18mm plain mdf, 42" long.

One end reads 104.29mm, the other 104.25mm (nothing wrong with that! :wink: )
Some of the 'lows' along the cut measure 103.97, 103.88, 103.77.

A lenght of pine lam-board 5ft long

One end reads 82.59mm the other 82.52mm (again, not going to fault that!!)
The lowest dips measure 82.08mm and 82.06mm.

Ok, it looks as if I'm being pedantic worrying about what would appear to be minute meausurements, but theyre enough to not give a good true cut and allow chinks of light through and thus have to have a plane ran over them to true them up (ok, I expect to have to run a plane over edges at times to remove saw marks, but not to remove peaks and troughs).

Am I expecting too much of my saw, is a true, perfect cut off a table saw a reality?

What I was really after was the distance between the low points, are the regular or random? I do not think a distorted blade would give you lots of low points, its just that the overall dimension of the board may be out depending on what part of the blade you made the measurement from.

 

[motownmartin]

I get over this problem using anti kickback rollers angled towards the fence, it doesn't work if you are cutting thin strips though.

 

[CroppyBoy1798]

I was trying her out today, doing a few tests and getting mixed results! Like, for instance, I got a 1" thick piece of pine lam-board approx 2ft square, cut one side with the sliding table....perfectly straight, then flipped it over and cut the opposite side using the rip fence and I got some light showing, both cuts were cross cuts. #-o When ripping lenghts of 18mm chipboard newt the results didnt seem consistant, some had a single low running from one end to the other (with a few inches at the start and finish being perfectly flat), others has two or so 'lows'....

Anyway, some pictures to reward you all for your help! =D>

Been busy pimping her up the past couple of day! I added a drop down router table/run off bench (the brackets for that took a little while to get working correctly!!) and also a mobile base. Everything has to be mobile and compact as I'd a tad tight on space. I'll tell you, those little Aldi arc welders are the biz! One of the best tools I ever bought in the place!

You'll probably notice the lack of a guard, well, the saw came with a 'home made' riving knife (I think it was just the original that someone had butchered!) I do have the guard and only toninght added a vacuum attachment to it, so, have to get a new knife cut out.

 

[newt]

Is the riving knife narrower than the blade (it should be) and is it centred on the blade, this may be something to do with you problem. Clearly the work is getting closer to the blade during the cut but not at each end, it could be technique eg relaxing the side pressure towards the rip fence during the cut.

 

[CroppyBoy1798]

I think I got it sorted, or at least I'm getting a lot better cuts than I was getting! It was all down to the fence, it wasnt exactly (and I mean 'exactly') parrallel with the mitre slots and was being slightly distorted when I'd tighten on the wooden face piece. The fence is only folded sheet metal and I think its missing a bottom insert that would have provided some strenght, so I made up and oak insert and popped it into it.

Glad I got that one sorted, happy now! Got a proper knife cut too and the guard with dust extraction attachment fitted, so she's ready to rock and roll next week (20 kitchen cabinet doors and 4 hotpress doors! (hammer)

Thanks for all the help and suggestions.

 

[Steve Maskery]

CB, I can't help you with your problem, but your riving knife is miles out. It should be no more than 8mm from the teeth at bed level, yours appears to be several inches. It can't do its job properly.

S

 

[jumps]

CB, I can't help you with your problem, but your riving knife is miles out. It should be no more than 8mm from the teeth at bed level, yours appears to be several inches. It can't do its job properly.

S

indeed - and that could easily reflect back off the fence to create variation (but obviously not from a sled)

almost looks like the blade is undersized?

 

[Anonymous]

Steve is spot on, Thats your biggest problem the knife is far too far away from your blade.

as others have said, the kerf of the blade, must match the kerf of the riving knive.