Having trouble with your Festool power tool? Well, we're here to help you. Before posting to the forum, give us a chance to diagnose and resolve your issue. In the U.S. and Canada, call us toll-free at 888-337-8600 on Monday-Friday between 8a-5p EST or contact us via email at service@festoolusa.com. For other countries, please visit http://www.festool.com for contact information for your local Festool service department.

Author Topic: Plunge Saw Advise  (Read 19063 times)

0 Members and 1 Guest are viewing this topic.

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #30 on: November 02, 2011, 11:50 AM »
1/32" over what distance?

Also, the rails "rail" or "hump" is a good, but not perfect, means to keep the rail straight.... Of course, within the limits of the real world practical use for what they were intended for... ya have to treat these rails gentle...

I think Festool designers were balancing weight considerations vs. rigidity.     
« Last Edit: November 02, 2011, 12:01 PM by JSands »

Festool USA does not pre-approve the contents of this website nor endorse the application or use of any Festool product in any way other than in the manner described in the Festool Instruction Manual. To reduce the risk of serious injury and/or damage to your Festool product, always read, understand and follow all warnings and instructions in your Festool product's Instruction Manual. Although Festool strives for accuracy in the website material, the website may contain inaccuracies. Festool makes no representations about the accuracy, reliability, completeness or timeliness of the material on this website or about the results to be obtained from using the website. Festool and its affiliates cannot be responsible for improper postings or your reliance on the website's material. Your use of any material contained on this website is entirely at your own risk. The content contained on this site is provided for informational purposes only and does not constitute professional advice.


Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #31 on: November 02, 2011, 07:33 PM »
We were discussing the FS 3000 and FS 5000 guide rails.  You'd have to ask him about the acceptable tolerance on the shorter length rails.

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #32 on: November 02, 2011, 07:58 PM »
so on the 3000,  1/32nd / 10ft is 1/320th, or .003" per ft, decent....

on the 5000,  .002" per ft.... even better.... 

from my experience, they are prob. closer to 1/64th...

Problem is, my Starett Straight edge (the longest straight edge I own) is only 6ft...
hard to find a suitable reference edge...


Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #33 on: November 02, 2011, 08:01 PM »
David was saying that 1/32" variance over those longer lengths is acceptable from the aluminum extrusion process.  He didn't state what the tolerance was exactly.  A spec like that might have to come from Germany.

Offline Tom Bellemare

  • Inactive Member
  • *
  • Posts: 5148
  • Festool demo's & personal service in Central Texas
Re: Plunge Saw Advise
« Reply #34 on: November 02, 2011, 08:46 PM »
1/32" is 31 thousandths and change. That's not much over a long distance, especially if the object being measured is not milled.

I have designed a lot of metal parts where +/- 15 thousandths was the default tolerance for machining. I wouldn't consider 30 thousandths to be out of consideration for a 4' extrusion.

Absolute dimension definitions help the manufacturer and the designer meet the requirements of the tasks for which something is intended. Using that method, the overall requirements are defined and the mfr. is allowed more leash. If David is referring to an absolute dimensional requirement, it makes sense that the length of the rail doesn't matter.

My experience with Festool Guide Rails is that they are really accurate if used properly and never abused prior to use. As I stated in a previous post, I can bend aluminum. If the rail, which has a sticky strip component on the bottom, is place on the work piece under stress, it can be crooked. The key, even with shorter rails, is to relieve all stresses as they are placed on the work piece.


Tom

Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #35 on: November 02, 2011, 08:52 PM »
1/32" is 31 thousandths and change. That's not much over a long distance, especially if the object being measured is not milled.

I have designed a lot of metal parts where +/- 15 thousandths was the default tolerance for machining. I wouldn't consider 30 thousandths to be out of consideration for a 4' extrusion.

Absolute dimension definitions help the manufacturer and the designer meet the requirements of the tasks for which something is intended. Using that method, the overall requirements are defined and the mfr. is allowed more leash. If David is referring to an absolute dimensional requirement, it makes sense that the length of the rail doesn't matter.

My experience with Festool Guide Rails is that they are really accurate if used properly and never abused prior to use. As I stated in a previous post, I can bend aluminum. If the rail, which has a sticky strip component on the bottom, is place on the work piece under stress, it can be crooked. The key, even with shorter rails, is to relieve all stresses as they are placed on the work piece.

Tom

Who's gonna pay for all that therapy or should I play one of those crashing waves cd's for my guide rails?

Offline Tom Bellemare

  • Inactive Member
  • *
  • Posts: 5148
  • Festool demo's & personal service in Central Texas
Re: Plunge Saw Advise
« Reply #36 on: November 02, 2011, 08:55 PM »
Go to Hawaii...


Tom

Offline andvari

  • Posts: 423
Re: Plunge Saw Advise
« Reply #37 on: November 02, 2011, 10:17 PM »

A 12' straight edge for checking runway flatness goes for $1500 or so. It is spec'ed +/- 0.012" Maybe with one of these you could get the straightness you are looking for.

TS55, Domino 500, Domino Assortment, OF1400, CT36+Boom Arm, T12+3, FS3000, Parallel Guides, RO 90, ETS 150/3, Domino XL, Domiplate, LS130, RTS Guide Stop, CMS-GE, Carvex 420

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #38 on: November 02, 2011, 10:56 PM »
>  A 12' straight edge for checking runway flatness goes for $1500 or so. It is spec'ed +/- 0.012" Maybe with one of these you could get the straightness you are looking for.

           
                      Not sure who you were responding to....but if it was me, as I wrote above, I am more than happy with my 64th over 8ft, for the cost of the rail, ya can't ask for more in ww......  possible you were responding to another poster, or did not read the thread....

But I am curious of the straight edge you refer to of that length and cost?   Got a link?   
My guess is, at 12' it would be hard to keep the straight edge "straight" as just the weight of it alone would make it change dimension a bit...?

Offline RL

  • Posts: 3040
Re: Plunge Saw Advise
« Reply #39 on: November 02, 2011, 11:15 PM »
Piqued my interest so I did a search on the subject...

http://www.concentric.net/~Petsch/Runway/RunwayStraighEdge.htm


Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #40 on: November 02, 2011, 11:31 PM »
Great find Richard!   thx for posting, very interesting web page...

>  0.012-inch maximum deviation over 144 inches


that breaks down to about a thou per ft....  darn good considering the length... and tremendous light weight...  for 12ft, 25 lbs at 1x4" dimension.... 

at $1700 delivered, shows the value of Festool long rails...



Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #41 on: November 02, 2011, 11:47 PM »
I'm getting one.  I'm going to check everything under the sun.

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #42 on: November 03, 2011, 09:34 AM »
in forums, its hard to extrapolate humor / sarcasm....

are you really getting one, if so, for what?

gotta admit, it is a cool find....can't think of any ww applications I do that would justify that price....
but if I had one, or access to one, I would prob. start checking stuff just for curiosity....

Offline wooden

  • Posts: 319
Re: Plunge Saw Advise
« Reply #43 on: November 03, 2011, 10:25 AM »
I'm getting one.  I'm going to check everything under the sun.

My friend has an SCMI jointer.  Beds are literally large enough to land a jumbo jet and flatter than lake Avalon on a windless day.

I was shocked to learn that my 2x10 lumber is out by 2548 inches over 8 feet of length!!!!!!!!!

Offline greg mann

  • Posts: 1936
Re: Plunge Saw Advise
« Reply #44 on: November 03, 2011, 11:16 AM »
There was a 'discussion' over on Sawmill Creek about router table flatness and the term +/-.002 was invoked by router guru Pat Warner. I posted a comment that flatness should not be described as a +/- tolerance as it adds confusion to the discussion. The same is true for straightness, perpendicularity, parallelism, roundness, cylindricity, and so on. In all cases where one is describing a geometric form tolerance, zero represents perfection and the deviation is always described as a positive value. Why does it matter? Well, when one says +/-.002 do they mean .002 total variation (supposedly either plus or minus) or .004 total (from one extreme to the other)?

As an example, one can describe straightness more accurately by saying a rail is .010 out-of-flat in a concave or convex condition, or, that the rail is .010 OOF in both (snake shaped).  Then, there can be a discussion about which condition may be more desirable and when. In the case of a router table I would suspect that being convex, with the area immediately surrounding the bit being the highest spot, would be the most desirable form of deviation. For a rail it probably makes little difference, with one case being better sometimes and the other case being better on another occasion.

I asked Pat to clarify what he meant but so far I did not get a direct answer. He did say that his RT was flat within .002 within a 10 inch circle around his bit, so I am going to interpret that to mean he thinks a flatness within .002 total is acceptable. If that is the case, and he wants to continue to use +/- terminology, then he should at least change his description to +/- .001. How much clearer might it be to just say .002 total variation?
Greg Mann
Oakland, Michigan

Offline greg mann

  • Posts: 1936
Re: Plunge Saw Advise
« Reply #45 on: November 03, 2011, 11:17 AM »
1/32" is 31 thousandths and change. That's not much over a long distance, especially if the object being measured is not milled.

I have designed a lot of metal parts where +/- 15 thousandths was the default tolerance for machining. I wouldn't consider 30 thousandths to be out of consideration for a 4' extrusion.

Tom

Tom gets what I mean.  ;D
Greg Mann
Oakland, Michigan

Offline Alex

  • Posts: 7785
Re: Plunge Saw Advise
« Reply #46 on: November 03, 2011, 12:39 PM »
Well, when one says +/-.002 do they mean .002 total variation (supposedly either plus or minus) or .004 total (from one extreme to the other)?

+/-.002 means it can be .002 in either one direction or the other, so a possible total of .004.

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #47 on: November 03, 2011, 04:09 PM »
Gregs point is, for flatness, its simply a given value from flat.....

Thicknesses are +/- tolerance values...

router table flatness matters.... I have done lots of edge working that never comes out as perfect as I would like...the reason is, the flat piece takes on the unevenness of the table...
when something is critical, I use a trim router, as the base is over a small area of the piece being routed....

Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #48 on: November 03, 2011, 06:53 PM »
in forums, its hard to extrapolate humor / sarcasm....

are you really getting one, if so, for what?

gotta admit, it is a cool find....can't think of any ww applications I do that would justify that price....
but if I had one, or access to one, I would prob. start checking stuff just for curiosity....

Sarcasm.  If I had one, I'd most likely go nuts finding imperfections in everything.  [big grin]

I don't understand what's so hard about understanding what tolerance means? [unsure]  Alex gets it.

I've seen tolerances also expressed in something like this manner:  +0.002" / -0.006".     When the deviation is the same in both directions, then there's no need to write +0.002" / -0.002" instead it's expressed simply as +/- 0.002".
« Last Edit: November 03, 2011, 07:00 PM by Ken Nagrod »

Offline pugilato

  • Posts: 579
  • Pugilato is not really my name... Andy
Re: Plunge Saw Advise
« Reply #49 on: November 03, 2011, 08:12 PM »
you should try the mean +/- one standard deviation of the population of measurements, which is a typical measure of uncertainty.  That's when it starts getting fun...

Offline greg mann

  • Posts: 1936
Re: Plunge Saw Advise
« Reply #50 on: November 03, 2011, 11:43 PM »

A 12' straight edge for checking runway flatness goes for $1500 or so. It is spec'ed +/- 0.012" Maybe with one of these you could get the straightness you are looking for.



Well, here ya go. Andvari references a runway flatness gauge and says it is spec'd at plus or minus .012".  Not so. The actual tolerance of the gauge is .012 TOTAL, which is, of course, half as much deviation. My guess is that making a runway flat to .125" per 12 feet is an order of magnitude more difficult than .250" per 12 feet.

All I am suggesting is that we clarify what these values really mean when we use them. When we say plus or minus are we really implying the total deviation or are we just being careless? The difference is not insignificant. Like the difference between one inch and two.

Greg Mann
Oakland, Michigan

Offline greg mann

  • Posts: 1936
Re: Plunge Saw Advise
« Reply #51 on: November 03, 2011, 11:54 PM »
Well, when one says +/-.002 do they mean .002 total variation (supposedly either plus or minus) or .004 total (from one extreme to the other)?

+/-.002 means it can be .002 in either one direction or the other, so a possible total of .004.

This is true when you are referencing size, like diameter or thickness, but it is not helpful for geometric features where perfection is represented by zero deviation. Without special clarification, such as concave or convex, in which either would be described as a plus value, tolerances of form are always uni-directional. In your example, Alex, the tolerance should be described as .004. If it is used to describe straightness.
Greg Mann
Oakland, Michigan

Offline Tom Bellemare

  • Inactive Member
  • *
  • Posts: 5148
  • Festool demo's & personal service in Central Texas
Re: Plunge Saw Advise
« Reply #52 on: November 04, 2011, 12:21 AM »
Greg:

I'm not sure a GD&T discussion is valuable here... or maybe it is.


Tom

Offline JSands

  • Posts: 194
Re: Plunge Saw Advise
« Reply #53 on: November 04, 2011, 12:52 AM »
Greg is nutz on.....


Offline Ken Nagrod

  • Posts: 3438
Re: Plunge Saw Advise
« Reply #54 on: November 04, 2011, 01:16 AM »
Ok, I just fixed it.  Greg is now banned from all woodworking forums and anything that uses the word "wood".  All he'll see is an empty vortex on his screen.  Now everyone else can relax.  We are back at DEFCON 5.  [cool]