Jump to content




Photo

When a carpenter does metalworking...


  • Please log in to reply
30 replies to this topic

#1 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 8,491 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 20 February 2017 - 09:25 AM

...he's going to do "stoopid" stuff.  Here's one that bit me more than once already.  When you advance a cutter into a piece of spinning metal .002", the result will be a reduction in diameter of .004".  Seems obvious right?  You'd think that having made the mistake once I wouldn't repeat it right?  Well, you'd be wrong!  :D


  • slotbaker, Tex, garyvmachines and 2 others like this
John Havlicek




#2 Racer36

Racer36

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 287 posts
  • Joined: 09-October 11
  • Gender:Male
  • Location:St. Catharines, Ontario, Canada

Posted 20 February 2017 - 09:32 AM

Radius, diameter..... it's all so confusing eh?
  • havlicek likes this

Dennis Dominey

Lifelong half-assed slot racer


#3 Racer36

Racer36

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 287 posts
  • Joined: 09-October 11
  • Gender:Male
  • Location:St. Catharines, Ontario, Canada

Posted 20 February 2017 - 09:33 AM

BTW, that green Can is still here with your name on it. Soon!

Dennis Dominey

Lifelong half-assed slot racer


#4 Pablo

Pablo

    Builder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 11,815 posts
  • Joined: 20-February 06
  • Gender:Male
  • Location:Johnson Bayou

Posted 20 February 2017 - 10:11 AM

OK I'm confused, too. Remove 2 thou of radius and the OD is reduced 4 thou.

What am I missing ?


Paul Wolcott

#5 wbugenis

wbugenis

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 232 posts
  • Joined: 17-December 09
  • Gender:Male
  • Location:Brooklyn, NY

Posted 20 February 2017 - 10:15 AM

On a lathe, with the material spinning, you are removing .002" from both near and far sides of the workpiece.

 

2 + 2 = 4


  • havlicek and Jason Holmes like this
William Bugenis

#6 Half Fast

Half Fast

    Keeper Of Odd Knowledge

  • Subscriber
  • PipPipPipPipPipPip
  • 1,457 posts
  • Joined: 02-May 07
  • Gender:Male
  • Location:NYC, Long Island

Posted 20 February 2017 - 10:22 AM

I thought there was going to be no math on this blog :)

 

Cheers


  • Samiam likes this

Bill Botjer

Faster then, wiser now


#7 MSwiss

MSwiss

    Grand Champion Poster

  • Advertiser
  • PipPipPipPipPipPipPipPip
  • 16,976 posts
  • Joined: 16-April 06
  • Gender:Male

Posted 20 February 2017 - 10:43 AM

I think Pablo misunderstood John's last line.

"Well, you'd be wrong".

And thus, Bill Bugenis misunderstood Pablo's post.
  • havlicek likes this

Mike Swiss
IRRA® Components Committee Chairman
Five-time USRA National Champion (two G7, one G27, two G7 Senior)
Two-time G7 World Champion (1988, 1990)

Eight-time G7 King track single lap world record holder (pointless era - LOL)
 
Chicagoland Raceway
17B West Ogden Ave
Westmont, IL 60559
(708) 203-8003
mikeswiss86@hotmail.com (also my PayPal address) 
Note: Send all USPS packages and mail to: 5858 Chase Ave., Downers Grove, IL 60516. Make checks out to Chicagoland Woodworking, Inc.


#8 old & gray

old & gray

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 337 posts
  • Joined: 15-April 11
  • Gender:Male
  • Location:CT

Posted 20 February 2017 - 10:45 AM

Long ago in a machine shop where I worked the OD grinding machines were setup with dials which read in diameter reduction. (set dial to .012, reduce diameter .012"). Then they brought in a new machine from Germany, the dials indicated the stock removal from each side in millimeters. Between the change from radial to diametrical and the mm to inch conversion the scrap was epic. 

 

John you have nothing to be ashamed of.  


  • proptop, havlicek, Dave Reed and 1 other like this
Bob Schlain

#9 Bill from NH

Bill from NH

    Age scrubs away speed!

  • Full Member
  • PipPipPipPipPipPipPipPip
  • 7,885 posts
  • Joined: 02-August 07
  • Gender:Male
  • Location:New Boston, NH

Posted 20 February 2017 - 11:32 AM

Radius, diameter..... it's all so confusing eh?

 

Dennis, think:   radius=diameter/2


Bill Fernald

When chemists die, they barium.


#10 garyvmachines

garyvmachines

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 431 posts
  • Joined: 30-May 11
  • Gender:Male
  • Location:Granite Planite - Granite City, IL

Posted 20 February 2017 - 12:44 PM

My Old Dad taught me.....MEASURE .... TWICE ( 2 times ) ..... cut Once..... !!!

I always cut a small place... Stop... & measure ..... Adjust if needed .... Make cut......

You will have not messed up your part... try it  & have FUN..... you should see my carpenter scrap BOX !!!!

 

GAV  


  • tonyp and MarkH like this
Gary Vogeler

#11 Racer36

Racer36

    On The Lead Lap

  • Full Member
  • PipPipPipPip
  • 287 posts
  • Joined: 09-October 11
  • Gender:Male
  • Location:St. Catharines, Ontario, Canada

Posted 20 February 2017 - 02:16 PM

Bill
I was at school the day they taught that. I was being facetious.

Dennis Dominey

Lifelong half-assed slot racer


#12 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 8,491 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 20 February 2017 - 03:05 PM

 

 

John you have nothing to be ashamed of.

 

Thanks Bob.  I'm not really ashamed, otherwise I wouldn't be broadcasting this stuff!  Anyway, I suppose if I had done any wood turning I'd probably be tuned-in to this, but that's a pond I've never dipped my toes in!


John Havlicek

#13 wbugenis

wbugenis

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 232 posts
  • Joined: 17-December 09
  • Gender:Male
  • Location:Brooklyn, NY

Posted 20 February 2017 - 03:07 PM

"What we've got here is failure to communicate

 

Cool Hand Luke  (1967)

 


  • Dave Reed, boxerdog, gotboostedvr6 and 1 other like this
William Bugenis

#14 Dave Crevie

Dave Crevie

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 519 posts
  • Joined: 16-February 09

Posted 20 February 2017 - 03:11 PM

Most quality lathes are graduated according to reduction of diameter on the cross slide. So you can usually

take just what the dial says, i.e. two thousanths on the dial reduces the diameter of the workpiece two thousanths.

It is the compound slide that can trip you up. They are usually graduated for linear movement, so if you use it to

make diametrical cuts you have to take only one thousanth on the dial to make a two thousanth reduction of the

part.

 

Maybe you should invest in a DRO. LOL



#15 Benno - SAC

Benno - SAC

    Beyond the Atlantic

  • Full Member
  • Pip
  • 39 posts
  • Joined: 25-January 17
  • Gender:Male
  • Location:Germany

Posted 20 February 2017 - 04:36 PM

:dash2: :dash2: :dash2:  I put a nonius scale on my Hudy tire truer and was wondering, why it does not work proper. :sarcastic_hand:

 

Thank you John for this thread! :good:

 

Oh, by the way, two of my ancestors where carpenters too :laugh2: :laugh2: :laugh2: .


  • havlicek likes this

Schöne Grüße (Kind regards)

Benno Stolberg

 

If I make mistakes, please let me know so I can improve my English.

 

www.SAC-Stolberg.de


#16 Matt Sheldon

Matt Sheldon

    Duffy HMI Executive

  • Full Member
  • PipPipPipPipPipPip
  • 1,581 posts
  • Joined: 19-January 10
  • Gender:Male
  • Location:Platteville, CO

Posted 20 February 2017 - 06:15 PM

John,
 
Just think of it as cutting on the light or heavy side of the line, LOL
  • havlicek likes this

Matt Sheldon

 

 

 

 

 

 

 

 


#17 Mach9

Mach9

    Mid-Pack Racer

  • Full Member
  • PipPipPip
  • 159 posts
  • Joined: 27-June 12
  • Gender:Male
  • Location:NC

Posted 20 February 2017 - 08:13 PM

Measure it with a micrometer, mark it with chalk, cut it with an axe.


  • Pappy and garyvmachines like this

Mack Johnson
'86 Mustang footbraker
6.435 @ 104 MPH
NC Slot Car Tracks - Past and Present


#18 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 8,491 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 21 February 2017 - 06:26 AM

John,
 
Just think of it as cutting on the light or heavy side of the line, LOL

 

:)  Some years ago I was training a guy to make cuts I called out while on a ladder.  One of the measurements I called was either a "light" or "heavy" number and, needless to say, I had to get down off the ladder.  

  Then too, my miter saw has a laser line, and the same guy kept trying to make his cuts using the laser instead of marking them.  I told him to turn off the laser and don't turn it back on.

Generally, marking cuts on wood is sort of like shooting targets with a pistol.  The finer the line ("smaller the target"), the more accurate the cut.  For framing, a regular carpenter's pencil is fine if you keep it sharp.  For trim, a regular #2 pencil really sharp works better.  If you really want to keep things close, you can even use a utility knife to mark the cut.  For cuts closer than that, you just slide the piece to the blade, raise the blade and lower it to lose "a hair"...you don't mark it at all!  :)


  • Matt Sheldon and garyvmachines like this
John Havlicek

#19 tonyp

tonyp

    Grand Champion Poster

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 13,162 posts
  • Joined: 12-February 07
  • Gender:Male
  • Location:Sanford, FL, land of lizards and big roaches

Posted 21 February 2017 - 07:42 AM

I tend to eye it up, cut and file a lot. Lol.
  • havlicek, Mike Patterson, Dallas Racer and 2 others like this

"And if my thought-dreams could be seen they'd probably put my head in a guillotine. But it's alright, Ma, it's life, and life only." - Dylan

1965 "Evil Bucks Racer" Team
Revtech Team Trinity
Noose Painted Bodies
Retro East co-founder
American King track single lap world record holder & 40 minute total lap record
First IM Nationals Champion
Arco Champion
Car Model Magazine Series Amateur Champion
2016 ORS Anglewinder Constructors Championsh
ip


#20 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 8,491 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 21 February 2017 - 08:11 AM

I tend to eye it up, cut and file a lot. Lol.

 

Me too Tony, although my end-result seems to fall way short of yours...dagnabbit!


John Havlicek

#21 B.C.

B.C.

    Mid-Pack Racer

  • Full Member
  • PipPipPip
  • 183 posts
  • Joined: 30-September 08
  • Gender:Male

Posted 21 February 2017 - 11:57 AM

I have received several thank you notes from solder suppliers thanking me for buying more of their products

 

than anyone else. I have no choice, it takes a lot of solder to cover up my mistakes in cutting and measuring

 

when I build a frame. I also end up with 200 gram cars for can am. I was taught that if a little solder is good, a

 

lot of solder is great. my chassis builds are known as rolling solder blobs.


  • Danny Zona likes this
Brian C. Bays

#22 Dallas Racer

Dallas Racer

    Checkered Flag in Hand

  • Full Member
  • PipPipPipPipPipPip
  • 1,450 posts
  • Joined: 03-November 07
  • Gender:Male
  • Location:Dallas, TX

Posted 21 February 2017 - 01:15 PM

Having never used anything other than a com lath, I didn't know that either and would have made the same mistake.

 

I did trim work back in the 80's for a 2-3 years. We used the terms "shy" and "full". 50 5/16" full would mean 50 11/32". Shy would be 50 9/32".

 

I'm surprised framers would need such accuracy. I thought +/- 1/4" was close enough. ;)


Phil Smith ® ™


#23 Dallas Racer

Dallas Racer

    Checkered Flag in Hand

  • Full Member
  • PipPipPipPipPipPip
  • 1,450 posts
  • Joined: 03-November 07
  • Gender:Male
  • Location:Dallas, TX

Posted 21 February 2017 - 01:27 PM

I tend to eye it up, cut and file a lot. Lol.

 

I used to build I15 chassis' on a block with a center-line and a cross-line toward one end. I used the cross-line to eyeball the axle, centered everyting off the center-line and did a lot of overall eyeballing. Somehow they'd end up within 1/64" or better accuracy and I could build one in 4 -8 hours, including cutting out spring steel nose pieces. Now i have a fancy jig block and takes me 2 weeks and they're not as good as the non-jig chassis.

 

It's hell getting old. :D


  • tonyp likes this

Phil Smith ® ™


#24 Booger

Booger

    Backmarker

  • Subscriber
  • PipPip
  • 91 posts
  • Joined: 15-June 15
  • Gender:Male
  • Location:SoCal

Posted 21 February 2017 - 09:32 PM

You can set the compound at 30*,feed the depth with the compound (not the cross slide) and it will read directly.....IF that is easier for you.


Gary "Booger" Baker

#25 havlicek

havlicek

    OCD Rewinder

  • Subscriber
  • PipPipPipPipPipPipPipPip
  • 8,491 posts
  • Joined: 20-August 07
  • Gender:Male
  • Location:NY

Posted 22 February 2017 - 07:23 AM

You can set the compound at 30*,feed the depth with the compound (not the cross slide) and it will read directly.....IF that is easier for you.

 

I don't know what that means, but I love it when guys talk all "technical"!  :D


John Havlicek

#26 Eddie Fleming

Eddie Fleming

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 552 posts
  • Joined: 27-April 14
  • Gender:Male
  • Location:Fayetteville, GA

Posted 22 February 2017 - 08:45 AM

You can set the compound at 30*,feed the depth with the compound (not the cross slide) and it will read directly.....IF that is easier for you.

I am not a machinist and I don't have a lathe but I think I see what you are saying. Can you explain why 30* and not 45*. Or I may be off in left field.  


Eddie Fleming

#27 wbugenis

wbugenis

    On The Lead Lap

  • Subscriber
  • PipPipPipPip
  • 232 posts
  • Joined: 17-December 09
  • Gender:Male
  • Location:Brooklyn, NY

Posted 22 February 2017 - 09:13 AM

Geometry:

 

Given a 30, 60, 90 right triangle,

 

the side opposite the 30 degree angle is  half (recall that half is the relevent value here)

 

the length of  the side opposite the 60 degree angle.

 

I'm sure someone will provide a diagram which will make it clearer.

 

26 posts on dividing by two!    Who would of thunk it? 


  • Half Fast likes this
William Bugenis

#28 Eddie Fleming

Eddie Fleming

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 552 posts
  • Joined: 27-April 14
  • Gender:Male
  • Location:Fayetteville, GA

Posted 22 February 2017 - 09:28 AM

Ok we are on the same page with the half but I don't know why half of 60 rather than half of 90. As I said I am not a machinist so help me along. the cutting tool is at a 90 to the part being cut?


Eddie Fleming

#29 Dave Crevie

Dave Crevie

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 519 posts
  • Joined: 16-February 09

Posted 22 February 2017 - 04:13 PM

The sine for 30 degrees is .5. If the compound is set at 30 degrees to spindle axis, moving the compound .001" will 

make a cut of .001" on the diameter rather than .002". The problem with doing this is that you now can not use the

compound for making facing cuts. Keep the compound aligned with the spindle axis so you can make facing cuts

with it rather than trying to use the carriage feed wheel to move the required amount. Whether the cross slide dial

is marked for radial cuts or diametrical, you will become accustomed to using it and won't make the mistake anymore.

Incidentely, in 50 years of turning metal, I have never used a lathe where the cross slide moved .001" for each mark

on the graduation. It usually only moves .0005" for each mark on the dial, including my old Unimat. Not to say they

don't exist, just that I have never seen it.


  • havlicek likes this

#30 Booger

Booger

    Backmarker

  • Subscriber
  • PipPip
  • 91 posts
  • Joined: 15-June 15
  • Gender:Male
  • Location:SoCal

Posted 27 February 2017 - 09:35 PM

The compound(or where the compound would be) holds the tool bit,the cross slide moves the complete compound....You don't HAVE to run a compound.....Lot's of folks don't,myself included.A couple lathes at work don't use them for various reasons.

 

Look underneath the compound and you will see a little window with numbers/hashmarks,those are the compound angles..

 

I use lathes at work that read both ways....Makes life interesting.... :laugh2:


Gary "Booger" Baker

#31 Dave Crevie

Dave Crevie

    Race Leader

  • Full Member
  • PipPipPipPipPip
  • 519 posts
  • Joined: 16-February 09

Posted 28 February 2017 - 03:43 PM

Never saw a commercial lathe that did not have a compound slide. Only way to cut angles manually.







Electric Dreams Online Shop