I am putting my new Powermatic together with some difficulties. The table is flat but when the extensions are bolted on there is a total bow up across the full width of the table. I removed the extensions and thoroughly cleaned the surface that bolts together with no improvement. Next I switched the extensions to the opposite sides with no improvements. Using the feeler gauge the gap is about .020. This appears to be pretty excessive considering the tolerance on the inspection form that came with the saw says .010. Any insight? <!—-><!—-> <!—->
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Replies
If they say .010" contact PM. It's not uncommon to add some shims to compensate. You can buy a few cheap feeler guages to compensate. I keep a pack of brass shim stock on hand for such things. Available from http://www.use-enco.com, http://www.mcmaster.com, http://www.mscdirect.com
I just put my 66 together and I used tin foil for shimming. Some use tape but I thought that it would compress to much. Brass shim stock is the proper material to use. Place the foil just above each bolt and fold it as needed to increase the thickness.
Nice saws, huh?
My 64A had the same problem. Shimmed it and it was fine. But I wasn't happy about it. Of course I had even worse problems with the (In)Accu-Fence.
Sorry to hear you guys have had the problem, but I'm happy to know it isn't just my lowly 64A that suffers from this.
I know nothing about a Powermatic.. However I have worked with cast-iron for many years...
Even stress relieved iron can warp.. Just like wood... If the inspection tag said a number, that is probably what was measured at the time the inspection was made. Most inspectors try to do their job right. (As in keep their job!).
No, I'm not sure why iron does that but I assure you it can happen. Sometimes you may even find some small cracks over time.. Again, I do not know why..
I have also seen extruded aluminum do it.
Will:
As you know,cast iron, as well as other metals, shrinks in volume as it passes from a liquid to a solid state. The fact that the sections of a casting are different in volume keeps the casting as a whole from reacting the same to the stresses caused from this shrinkage.I don`t know how Powermatic operates these days,but,I do know that in the early years,all the 'green' castings were piled up on the outside to reap the benefits of the sun and rain and ice and snow to equalize the stresses inherent in the raw castings.As the castings vary in thickness from section to section,the amount of stress and its location varies likewise.Now back to the thread:
If you will put a dab or two of aluminum or steel putty on the mating edges of the extention tables,and clamp the whole shebang to a front and back straight edge extending across the top of the table and extentions,and snug up the screws to squeeze out the extra putty,The result will be about as close as it will ever be.I have found that a strip from the mill edge of a piece Baltic Birch plywood makes a stisfactory straight edge for this purpose.If you are a purist and this is not satisfactory,you could take the whole assembly to a machine shop and have it surface ground. Some foundries place their rough castings in an oven for a perid of time to relieve the stresses. Work safely¬¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬Thank you,Mr.Croney,where ever you may be.
Work safely ¬¬¬¬¬¬¬¬¬¬PAT¬¬¬¬¬¬¬¬¬¬
reap the benefits of the sun and rain and ice and snow to equalize the stresses inherent in the raw castings.. I AGREE WITH YOU!Just nobody can afford to do that these days.. OR PAY for it... The all mighty buck!
The fact that the sections of a casting are different in volume keeps the casting as a whole from reacting the same to the stresses caused from this shrinkage.
I think that happen when I got old as I am!
Craig,
I went throught the same crap when I bought mine 2 years ago. It seems that Taiwann just can't get it done as well as Tennessee. Anyway, I actually put in about eight hours with a mill file filing the edges of the extension wings to get them right. I just couldn't stand the thought of having it that out of flat.
Good luck. Great saw once it's set up.
Jeff
I was under the impresion that shimming the CI extension wings is fairly normal practice. I also was under the impression that PM CI was still produced in USA. As well as everything else, except the hand wheels.
Jay
Taiwann!!
As far as shimming goes, mine was out .05. Way to far to shim. I called my local woodwerker's Supply, and he told me he had a similar complaint about the 66 from other customers at the time. Rather than haul it back to him, I decided to take the time and fix it myself, as there was no guarantee that the next one wouldn't be the same way.
Jeff
Edited 3/21/2005 7:54 pm ET by JHeath
Edited 3/21/2005 8:41 pm ET by JHeath
Hey Jheath,
.005 is too much to shim? What was your fix?
What is the resorce for the CI supply?
Jay
Jay
It was .05, not .005, which is even worse. My fix was to spend about 8 to 10 hours filing the wings down to fit. It's very flat now, which is extremely important to me. I'm a stickler (some call it anal) when it comes to setting up a tool. Its worth the extra time to set it up right the first time. The results show.
Jeff
J
I too have the AR/OCD thing. My table is very flat also. .05 still wasn't shimmable? Seems that .05 at 8.375" translates to.009" (shim) at the bottom or top of a 1.5 thick wing. A number of ways to skin a cat I guess. Wish I had brass shim stock but I used thin tin foil (candy wrapper .0008) folded a number of time to the proper thinckness.
Great to have the machine set up nice isn't it. Seems for guys like us, current production saws are more of a kit saw. The parts are there but set up is still a major undertaking. Tech guy only got me 10% of the way there. He didn't even shim the wings and they were also way out.
Any more info on the resource for CI for PM saws? Not that it matters a great deal but I am just curious. I was under the impression that all PM's but the 66 was Tiwanees.
J
Jay
I'm not an expert on Powermatic, but I know they used to be in Tennessee, and were bought by Jet. I guess everybody knows that stuff. All the packing stuff was from Taiwann, and the bolts, etc... were all metric. The castings are, to the best of my knowledge, from Taiwann. I could be wrong, but I'm 95% sure that I am not.
I have yet to buy a large power tool new, and not have to tinker with it. Some took more than others. I have an 18" bandsaw from Jet, and from what I've heard, I was lucky. I have had no problems with vibration, and can, and do, resaw all the time without any trouble. Set up was easy, and the blades track extremely well for me. I like to resaw and bookmatch all my door panels from 8/4 stock, so I do it frequently. In fact, I'll be resawing 13 panels tomorrow.
I didn't want to use shim stock because I had problems with them moving on me on my old unisaw. My old shop did not have a thermostat, and the heat up and cool down allowed enough expansion and contraction over the years to where I had to reshim several times, as the table became unflat again. At least, that's what I attributed it to. It could have just been the top itself, I guess, but I doubt it. In 2 1/2 years, my 66 top is still pretty darn perfect, but I still remember being out there until about 3:00 am filing down the sides of the wings, fitting, filing, fitting, filing, ......Oh, the nightmare is coming back!!!!!
That has been my experience. Now, I'm replacing all of the tools in my shop, 1 by 1, with old american cast iron. I have a 12 " Northfield jointer HD, which is like an aircraft carrier, a 20 " sanding disc from State, and an Oliver 270 table saw that I use for ripping thick stock and crosscutting. I'm gonna replace my 15" Jet planer with an Oliver 299 24" planer, as soon as I find one. I'm gonna replace my bandsaw with either a 36" Tannewitz or a 30 " Oliver, whichever I come across 1st. I had a 36" tannewitz, but a guy made me an offer I couldn't refuse, so I sold it. Made enough to get 2, in my opinion, but it was pristine, and he had to have it. I'm rambling, see ya.
Jeff
Cool on the shop improvements. I would love to go with all old tools.
WHM owns jet,pm and a number of other sub co's. PM is still on Tenn. The only tool PM makes (supposedly) in the US is the 66. Odd, all my fasteners were standard. Cheap but standard. I wonder who can shed some light on this. I have been told buy dealer they are..they arn't...some of it is....it was...... Comletly mixed bag of answers. The finish looks very different to that of the admitedly imported product. Doesn't mean that the cast is not imported then finsihed here or finished to different standards else where. WHo knows?
The Accu-Fence is still American made, but apparently they sub it out (or did). I have three in my garage. The first two were bad enough to be unusable, the third was good, but still not what I expected. I had to shim very slightly one of the faces to get both side perpendicular to the table.
The first two were a joke. The dealer (who has close ties to Jet selling their surplus and other stuff among new items) told me that one company that had been making the fences went out of business. So I don't know the details, but it sounded a little hokey. And they certainly had some big QC problems.
mine was out .005. Way to far to shim.???Geee .005 hardly a nats wing!
That was my thought. Think I shimmed out 1/16".
Sorry, typo. .05. Just edited original message. It looked like a bird getting ready to take off.
Jeff
I thought (.05) so but just 'HAD TO' get ya goat!
Cast Iron tops can distort if the machine isn't sitting perfectly level, or in the way the bolts holding it to the cabinet are tightened. Try leveling up the machine, loosening the bolts and tightening them back up. Needing to shim the wings a bit is typical.
Bob Lang
http://www.craftsmanplans.com
And then you move the saw and let it sit awhile!
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