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Lathe Test Bar Storage?

Uglydog

Active User
H-M Supporter-Premium
#1
I was doing a two collar test on my new lathe yesterday.
I'd already leveled her in plane.
Before I began the two collar test I thought I'd do a tailstock coarse adjust with a mandrel and a .0005 dial indicator.
I had a bucket of large mandrels that I've been pushing around the shop for a year (got'em at scrap value).
I'd sorted out the little ones already for a machine job this past summer.
Remaining were .75-2inch.
I found a really long one and rolled it on the surface plate to check cylindricity (qualitative).
Checked out nicely.
At this point I noticed that this ~1.25inch mandrel was about 18inch long.
Really long for a mandrel, or at least the ones I've used.
On closer inspection it was stamped "Test Bar" on the end.

SCORE!!

Question:
Yes, I need to find better storage for all of them....
Does anyone know if test bars (and mandrels) have "airy" points like straight edges?
Or, should the entire bar be supported?

I've hung my camel-back straight edges and horizontal arbors vertically.

Daryl
MN
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#4
I would wrap a piece of tool wrap around the test bar before putting in that hole. Maybe even go to the trouble to coat the ID of the wood block with a sealing wax. Minwax maybe? Not doing so could get rust on your test bar. Any chance of another test bar in you collection of mandrels? Ken

Edit: not tool wrap but VIC paper, I think that'd the correct abbreviation for it.
 

Uglydog

Active User
H-M Supporter-Premium
#5
Any chance of another test bar in you collection of mandrels? Edit: not tool wrap but VIC paper, I think that'd the correct abbreviation for it.
4gsr,
As I'm not excited about drilling a hole in the end of the test bar ;), I thought I'd make a box and hang the box. Coating the inside or sourcing VIC is a good idea. These "mandrels" looked pretty rough when I scored them. Rusty and dirty. They all cleaned up very nicely. Only a few with some pitting. This is the only really long one. I'll hope to check to see if anything else is stamped this weekend. This sure made dialing in the new lathe faster than a two collar test!

Thank you,
Daryl
 

Ulma Doctor

Infinitely Curious
Active Member
#7
i admit it's a bit low tech,
but a hunk of good cord , a clove hitch with two half hitches and you have a hanging arrangement that actually gets tighter as weight is applied
another simpler knot called a lark's head will do the same thing, as long as there is weight pulling on the knot , it will hold.
maybe even some high test fishing line could be employed for a floating visual effect ...:)
 
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Wreck™Wreck

Active User
H-M Supporter-Premium
#8
I work in a shop which currently has 5 lathes, we store test bars by not having any. I fail to see the utility of such a device as the work will be the test bar and account for all tool, part and machine flex in use. If however all of your work is turned in 1 pass this is not an option.
 

Cobra

Active User
H-M Supporter-Premium
#9
I work in a shop which currently has 5 lathes, we store test bars by not having any. I fail to see the utility of such a device as the work will be the test bar and account for all tool, part and machine flex in use. If however all of your work is turned in 1 pass this is not an option.
Why always with the attitude?
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#12
Be nice guys! We hate to lock this thread. Everyone has their own thoughts here for test bars. Let's keep it that way!
 

Heckle and Jeckle

Active Member
Active Member
#15
Maybe I am not understanding the concept of the test bar thing...

Unless the test bar allows a user to preform static indications for finding the tapper

Then I would ask, is there a difference, chuck up a chunk of round bar, cut measure and adjust if necessary, repeat until true?
 

Heckle and Jeckle

Active Member
Active Member
#18
As to this hanging a test bar up like clothes on a clothes line... I have heard the same bit regarding the storing of cranks.. However I have never seen a before and after measured example... that validates the THEORY, coin toss.
 

John Hasler

Active User
H-M Supporter-Premium
#20
I was doing a two collar test on my new lathe yesterday.
I'd already leveled her in plane.
Before I began the two collar test I thought I'd do a tailstock coarse adjust with a mandrel and a .0005 dial indicator.
I had a bucket of large mandrels that I've been pushing around the shop for a year (got'em at scrap value).
I'd sorted out the little ones already for a machine job this past summer.
Remaining were .75-2inch.
I found a really long one and rolled it on the surface plate to check cylindricity (qualitative).
Checked out nicely.
At this point I noticed that this ~1.25inch mandrel was about 18inch long.
Really long for a mandrel, or at least the ones I've used.
On closer inspection it was stamped "Test Bar" on the end.

SCORE!!

Question:
Yes, I need to find better storage for all of them....
Does anyone know if test bars (and mandrels) have "airy" points like straight edges?
Or, should the entire bar be supported?

I've hung my camel-back straight edges and horizontal arbors vertically.

Daryl
MN
Does your test bar have a taper to fit the spindle taper on your lathe?
 

Uglydog

Active User
H-M Supporter-Premium
#21
1inch on both ends.
I used it on centers.
Perhaps not ideal.
However, it makes it easily adaptable to many different lathes.

Daryl
MN
 

4gsr

Global Moderator
Staff member
H-M Supporter-Premium
#22
This will get me tossed from this forum I believe, so be it. EVERY PART TURNED IS A TEST BAR , if the part is small at one end and big at the other adjust the machine or your tooling choices. .....snip........k
I've done this many times over the years. It's kind of adjusting your machine on the fly! To get the taper out of the part you are cutting on.
It's not traditional in use as the two collar test method is, but it does work and is quite effective.

BTW- Wreck, we love you :grin: too much to run you off. Stay as long as you like. We need guys like you on the H-M forum.:)
 
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gi_984

Active User
Active Member
#23
I put sheets of VCI paper in every drawer of my cabinets and tool chests. I also keep those little packets of silica gel to put in the drawers. So far(knock on wood) I haven't found rust on my test bar, gage blocks, etc. My test bar is almost 1.5 inches in diameter and lays flat on a piece of rubber type drawer liner. I might have to find a new storage location. Please let us know the results accuracy wise.
 

Wreck™Wreck

Active User
H-M Supporter-Premium
#24
Maybe I am not understanding the concept of the test bar thing...

Unless the test bar allows a user to preform static indications for finding the tapper

Then I would ask, is there a difference, chuck up a chunk of round bar, cut measure and adjust if necessary, repeat until true?
You just broke the code my man, every part that you turn, mill or grind is a test before the finish operation, turn it, mill it or grind it to your desired finish allowance then dial in the finish size and have at it, sometimes it will finish larger or smaller then ideal, this is what tolerance bands are for.

If you were to request a quote from a shop for a small round part that will work just fine in use at say 1.000 +0-.005 diameter I would make you hundreds of them relatively cheaply, if however your tolerance band is 1.0005/1.0007 I would be forced to qoute at a MUCH HIGHER price.
 

Hotbluechips

Active Member
Active Member
#25
In my opinion the storage of "a test bar" is pretty basic. Don't damage it, don't let it rust, and don't use it for any other purpose.
Worrying about the thing bending from it's own weight, while sitting in a toolbox drawer, to me is silly.
Are you trying to machine to within millionths? This is the hobby machinist forum, not the NIST Laboratory.
At some point a little voice should whisper, It should be fine for me.
 

francist

Active User
H-M Supporter-Premium
#27
Some of the larger (read 1" and upwards) masonry drilling bits for roto-hammers and such often come in a nice threaded sleeve like that. Some of them must be close to two feet long.

-frank
 

ddickey

H-M Supporter - Premium Content
H-M Supporter-Premium
#29
This sure made dialing in the new lathe faster than a two collar test!
Daryl
Daryl,
Can you explain this. I was under a different impression such that the two collar was for identifying twist in the bed. Not sure what you would use a test bar for other then tailstock alignment between centers.
 

Uglydog

Active User
H-M Supporter-Premium
#30
It's been my understanding that they accomplish the same thing.
I've had similar results using both.
However, neither the two collar, nor the test bar replaces the use of a level.

As always I'm open to correction and redirection.

Daryl
MN
 
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