need help reading dial indicator

[mike malone]

i just finished John White's (taunton press), book on tuning up machinery and decided to test a PM 66 tablesaw for accuracy using his tests. I am just about finished doing the resto on the saw. However I don't really know how to read the indicator. (DUH!)

White suggests 0.003 as typical runout. Using a piece of copier paper, i get 2 "clicks" on the dial.
My arbor runout (3 tries) is 1-2/3 "clicks" (see photo)...I presume it is less than 0.002? (that's my guess, but never used a dial before, want to make sure) Can anyone help or verify? Thanks
I've included links to photos and a pic of the boook...(which is worth having, BTW)

[Chris Padilla]

Mike,

I'm not sure what you mean by "clicks" but starting from zero on your dial, spin the arbor and note along the way the change in deflection of the dial (can go either direction). You should be able to find a spot where it is the worse compared to your starting point.

You should pick 2-3 different starting points as well to make sure. If all 3 readings show the same spot and it is .002 " (or 2 mil), then that is the maximum runout of your arbor and I'd say you should be happy.

BTW, fantastic job on the Powermatic...that is just awesome! :D We need a little smilie/emoticon with a thumbs up!

[Carl Eyman]

You are reading dial right. Good looking paint job!

[Vaughn McMillan]

Can't add too much to the dial reading question, but man, that's an amazing restoration job! Are you sure the pics show the same saw?

- Vaughn

[mike malone]

hi
thanks for the kudos on the saw....as for the math i guess i could have worked at Enron.
very happy with two "clicks" or .002 runout.
tried it at several points on the arbor....same result
regards
m

[Rob Blaustein]

Wow, fantastic restoration! Agree with others (and you)--each hatchmark, graduation, or "click" on the dial is .001 inches. My copier paper seems to be a little thicker--around .004 inches (measured with a micrometer). That's also approximately the thickness of a dollar bill.

[Ken Fitzgerald]

Mike.......the easiest way to set up and use a dial indicator for this use......1) position it so that it touches the surface you want to measure and the shaft of the dial indicator is perpendicular to the surface you want to measure. 2) Make sure that the dial indicator is positioned such that it's shaft can move in or out (ie. you don't want it bottomed out at either end of it's shaft's travel range). 3) Loosen lock on the dial face and adjust the "0" point to be directly under the needle and retighten the dial face. 4) While rotating the arbor, note the maximum deflection reading you get. Note it's possible to get a reading less than "0"......for example ..... 0.998 (which you'd read -0.002)and say 0.003.......then add the two 0.002 + 0.003 = 0.005......... there is a more complicated way of adjusting and reading it but it's really not worth the effort for this type of use. Good luck! By the way....Nice Restoration!

[Jay Knepper]

Terrific restoration job! I'm not sure if I'm more impressed by the job itself or the speed with which you accomplished it, but I'm sure impressed!

[Alan Tolchinsky]

HI Mike, I really don't see any difference between the before and after pics. :)

O.K. I'm blind and crazy but I do have a question: What are your methods for cleaning up most of the saw? Do you sand blast or use some other techniques? Thanks and of course you've done a beautiful job on that saw as everybody has said. Alan

[Tyler Howell]

A beauty right down to the Baby Poop Mustard Yellow color.......Oh yes the gold standard:D .

Great restore and in a short time too.:cool:

[Richard Wolf]

Great restoration. Looks better than new.

Richard

[Bruce Page]

Mike, you did that in less that two weeks?!? Incredible. :eek:
You are showing a standard 1” travel indicator. Each division on the large dial is .001, and each revolution of the pointer equals .100
Ten times around the dial equals 1.000 or 1”. The smaller dial keeps track of the .100’s for you.

[mike malone]

Thanks Bruce...I just wasn't sure whether they were 100's or 1000's...now i know they are 1000ths.

[mike malone]

HI Mike, I really don't see any difference between the before and after pics. :)

O.K. I'm blind and crazy but I do have a question: What are your methods for cleaning up most of the saw? Do you sand blast or use some other techniques? Thanks and of course you've done a beautiful job on that saw as everybody has said. Alan

Hi Alan
Just the cabinet gets sandblasted....does wonders for the casters (not) casters and sand don't mix. The rest is mostly stripping and elbow grease. BTW Oven cleaner makes a pretty good paint remover. ...use lots of purple degreaser too. On some saws in the past I've had the tops blanchard ground, which gives a truly new surface...its just that it is a 70 mile drive to get it done and i hate driving. Thanks

[Greg Mann]

Mike,

Ken has it right, another way of saying 'total indicator runout'. His stressing the point of making sure the indicator shaft is perpendicular to the face is very important too. In the pictures it looks like you have tilted the arbor about 30 degrees while your indicator looks like it is about 45 degrees. I would suggest tilting the arbor all the way to 45 and resetting the indicator. You want to see how much dial movement you get. It does not matter if it is +.001 to -.001 or .008 to .010. Either way, you are looking for the total movement. (In the examples above it would be .002)

Now for the bad news. If you have .002' TIR near the edge of a 2 inch diameter flange that will translate into .010" TIR in a 10 inch blade as it is 5 times larger than the flange and will magnify the runout by that factor. Doesn't seem fair does it? Of course if you have .001 at the flange it will be .005 on the blade, and so on.

Greg

[Norman Hitt]

Hi Alan
On some saws in the past I've had the tops blanchard ground, which gives a truly new surface...its just that it is a 70 mile drive to get it done and i hate driving. Thanks

Fantastic job, Mike. I wish mine looked that clean and shiney. When you had the table tops Blanchard ground in the past, I'm curious as to about how much that cost in your area. Also, do they grind the top and extension wings while they are connected together, or do they Grind them separately?

[lou sansone]

as others have said... great restoration job...really looks good.

this shows that used equipement can be a good value if one wishes to rebuild it . now you know every part of the saw.

lou

[mike malone]

Fantastic job, Mike. I wish mine looked that clean and shiney. When you had the table tops Blanchard ground in the past, I'm curious as to about how much that cost in your area. Also, do they grind the top and extension wings while they are connected together, or do they Grind them separately?

hi norm.
table for a 12/14" delta was $120. (48" x 48" ish) the tops were ground together. One saw was so warped (30 thou), they sent it to a shop that annealed(?) it (1700 dergrees) and slow cooled it...then they ground it. The tops are placed on a magnetic table and you choose the finish you desire up to a polished finish. see attached pic...the photo is a little yellow..but you can see the basic result of the blanchard grinding.
thanks

http://hospitalqa.com/montage1.jpg

[Corey Hallagan]

Wow, that is an awesome job on that restoration. I am envious of you guys that restore this old stuff into working machines like that, probably looks better than it did new! Incredible transformation Mike, thanks for the photos.
Corey

[Rick Schubert]

Please excuse this question if it is really dumb, but when I try to test for runout on my new GI #50-250 cabinet saw using a dial indicator, the arbor does not turn by hand.

What am I doing wrong?

Thanks, Rick

[Norman Hitt]

hi norm.
table for a 12/14" delta was $120. (48" x 48" ish) the tops were ground together. One saw was so warped (30 thou), they sent it to a shop that annealed(?) it (1700 dergrees) and slow cooled it...then they ground it. The tops are placed on a magnetic table and you choose the finish you desire up to a polished finish. see attached pic...the photo is a little yellow..but you can see the basic result of the blanchard grinding.
thanks

http://hospitalqa.com/montage1.jpg

Boy, that Delta top really turned out nice. I need to check out the machine shops here one of these days, as my PM-66 top needs some attention. I had it stored for a while at my daughters house after I remodeled it, and the washing machine and dryer was also in that garage and SOMEONE laid a piece of metal about 6" wide and 3' long on it, and when I found it there was some rust under it. Since the guilty culprit, (a boyfriend of one of my daughter's friends) was told that I was not a happy camper, he decided to "Help me out", and used a disc sander to get rid of the rust. :mad: Needless to say, the top is not flat across the top anymore in that area, and I need to get it reground. At least since it is 14 years old, all the Stress should be out of it now, and it should remain flat forever, that is if I don't have anyone else decide to "Help Me Out". :D

Thanks for the info.

[Bill Lewis]

The good news is that if the indicator is at a 45 deg. angle to the arbor then the actual runout would only be about 70% (.707) of the total indicated runout.


Mike,

Ken has it right, another way of saying 'total indicator runout'. His stressing the point of making sure the indicator shaft is perpendicular to the face is very important too. In the pictures it looks like you have tilted the arbor about 30 degrees while your indicator looks like it is about 45 degrees. I would suggest tilting the arbor all the way to 45 and resetting the indicator. You want to see how much dial movement you get. It does not matter if it is +.001 to -.001 or .008 to .010. Either way, you are looking for the total movement. (In the examples above it would be .002)

Now for the bad news. If you have .002' TIR near the edge of a 2 inch diameter flange that will translate into .010" TIR in a 10 inch blade as it is 5 times larger than the flange and will magnify the runout by that factor. Doesn't seem fair does it? Of course if you have .001 at the flange it will be .005 on the blade, and so on.

Greg

[John Hart]

A beauty right down to the Baby Poop Mustard Yellow color.......Oh yes the gold standard:D .

Great restore and in a short time too.:cool:

Baby Poop Mustard Yellow!! Oh man, does THAT bring back some memories!!:eek:

Beautiful work Mike!! You are an artist!:)

[mike malone]

Please excuse this question if it is really dumb, but when I try to test for runout on my new GI #50-250 cabinet saw using a dial indicator, the arbor does not turn by hand.
What am I doing wrong?
Thanks, Rick

Rick...White suggests moving the v-belts by hand..not too easy, but it works
mike

[mike malone]

Boy, that Delta top really turned out nice. I need to check out the machine shops here one of these days, as my PM-66 top needs some attention. I had it stored for a while at my daughters house after I remodeled it, and the washing machine and dryer was also in that garage and SOMEONE laid a piece of metal about 6" wide and 3' long on it, and when I found it there was some rust under it. Since the guilty culprit, (a boyfriend of one of my daughter's friends) was told that I was not a happy camper, he decided to "Help me out", and used a disc sander to get rid of the rust. :mad: Needless to say, the top is not flat across the top anymore in that area, and I need to get it reground. At least since it is 14 years old, all the Stress should be out of it now, and it should remain flat forever, that is if I don't have anyone else decide to "Help Me Out". :D
Thanks for the info.

Hey Norm...that sort of stupidity really bites. that's why i don't like anyone to bring a beverage can into the shop as it always seems to get put on top of a saw or shaper table. I made a wooden shelf just for such purposes.
If you are looking for a blanchard grinder...most small shops can only do a piece no larger than 20"-30" in one direction. You want a place that has a dedicated machine with a 9' or 13' diam. table. Take off just enough to clean the surface up. Take off too much and your miter gauge will ride high and you'll have to surface the bottom of it.
BTW don't wear boots with steel toes...makes it real hard to walk on the "table" when the magnet is initialized.
regards
mike

[mike malone]

The good news is that if the indicator is at a 45 deg. angle to the arbor then the actual runout would only be about 70% (.707) of the total indicated runout.

hi Bill
Whites book suggests that .003 run out is acceptable as an industry standard
i may retry at true 45 deg and 90 deg and see what happens.
mike

[Greg Mann]

The good news is that if the indicator is at a 45 deg. angle to the arbor then the actual runout would only be about 70% (.707) of the total indicated runout.

Bill,

Sorry to disagree, but that is backwards. When the indicator is not square to the surface the apparent runout is less than the actual. As you probably know, since you had the value right for 45 degrees, this is called cosine error. But it gets applied the other way.

Edit,

Whoops, Bill is right!:o :o In the case of a plunger style indicator as Mike is using the apparent runout is more than the actual. With a pivoting stylus type of indicator, the opposite is true. That is what we use almost exclusively and was the cause of my faux paux. My apologies, Bill.

Greg