I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue what I
am talking about?

Jeff Lindemuth

A good way to remove scale after hardening is with sand blasting. You might
be able to do it chemically but that sounds dangerous (for both you and your
tools).

Out of curiosity, how are you grinding and lapping the gauge? Do you have a
cylindrical grinder? A lathe with a tool post grinder? Always looking for
new ways to do things...

Regards,

Robin


"Jeffrey Lindemuth" wrote in message
...
I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue what
I
am talking about?

Jeff Lindemuth

Jeff - Make'em in two parts: the gage from O-1 lapped etc, and the knurled
handle from SAE1020. Join the two with a taper fit.

"Jeffrey Lindemuth" wrote in message
...
I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue what
I
am talking about?

Jeff Lindemuth

"Jeffrey Lindemuth" wrote in message
...
I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue what
I
am talking about?

Jeff Lindemuth



If I was making the plug gage, and I didn't have a controlled atmosphere
furnace ( which I don't), I'd bead blast the entire gage after heat treat,
just before grinding. I'd heat treat the entire gage, not just the plug
end. Bead blasting removes all the scale and leaves a very pleasing
finish. All depends on the size of the media you use, of course. Very
fine sand (aluminum oxide, really) does a bang up job, too.

Harold

I found making plug gauges of smaller diameters way too much work, so I
started making the handle out of 12L14 knurled to suit, drilled holes into
each end, then crossdrilled and tapped for setscrews to hold appropriate
flatted pieces of either drill blank, or reamer blank. One of them is
supplied with plus tolerances, and the other is supplied with minus
tolerances. By choosing what I need, along with metric sizes available, I
have been able to all but eliminate scratch making most of the gauges we
use. Depths for hole testing can be established by grinding a V ring around
the blanks at the proper depth on the "go" end. It's heartbreaking to spend
a lot of time on a scratch built gauge, then have someone drop it onto a
concrete floor.

RJ

--
"Have no one say it, and say it to your shame, that all was well here, until
YOU came."




"Harold & Susan Vordos" wrote in message
...

"Jeffrey Lindemuth" wrote in message
...
I want to make a plug gauge using O1 tool steel. I am going to harden,
grind and lap the gauge and knurl the handle. So if I harden the entire
piece, how do I get the scale out of the knurls? Or do I heat the entire
piece, only quench the plug end, let the handle cool slowly keeping the
handle annealed, remove the scale and knurl? Or do I not have a clue
what
I
am talking about?

Jeff Lindemuth



If I was making the plug gage, and I didn't have a controlled atmosphere
furnace ( which I don't), I'd bead blast the entire gage after heat treat,
just before grinding. I'd heat treat the entire gage, not just the plug
end. Bead blasting removes all the scale and leaves a very pleasing
finish. All depends on the size of the media you use, of course. Very
fine sand (aluminum oxide, really) does a bang up job, too.

Harold

"Robin S." wrote in message
. ..
A good way to remove scale after hardening is with sand blasting. You
might
be able to do it chemically but that sounds dangerous (for both you and
your
tools).

Out of curiosity, how are you grinding and lapping the gauge? Do you have
a
cylindrical grinder? A lathe with a tool post grinder? Always looking for
new ways to do things...

Regards,

Robin


Thanks to Robin and Harold for the comments on sand or bead blasting. I did
not realize that sand blasting could remove the scale in the knurl. I try
and learn something new every day. I am off to a good start today.

I am going to use a tool post grinder on my 9 inch star lathe. I picked up a
Dunmore #14 at an auction recently. It is small, but taking lite passes and
grinding between centers, I think think it will be OK. This is a hobby
project, time is not a major concern.
For lapping, I am planning to use cast iron laps and lap on the lathe, as
described in modern toolmaking methods (1915).
Just seems like a neat project.

Thanks
Jeff

For lapping, I am planning to use cast iron laps and lap on the lathe, as
described in modern toolmaking methods (1915).

Just seems like a neat project.

And what more reason would be needed than that?

Errol Groff
Instructor, Machine Tool Department
H.H. Ellis Tech
613 Upper Maple Street
Danielson, CT 06239

860 774 8511 x1811

http://pages.cthome.net/errol.groff/

http://newenglandmodelengineeringsociety.org/

I find that if you are looking at anything under an inch in dia, then
pin gages are usually the easiest and cheapest route. They are available
in sizes from .004 to 1.0000 and in .0001 increments. The Travers
catalog gives prices at $8 to $15.50 each. Thats for the high tolerance
ones, the regular series are half the price.
A pin gage set comes in really handy around a shop. We used to fight
over them in the last shop I was at until I ordered another couple of
sets :-)

Backlash wrote:

I found making plug gauges of smaller diameters way too much work, so I
started making the handle out of 12L14 knurled to suit, drilled holes into
each end, then crossdrilled and tapped for setscrews to hold appropriate
flatted pieces of either drill blank, or reamer blank. One of them is
supplied with plus tolerances, and the other is supplied with minus
tolerances. By choosing what I need, along with metric sizes available, I
have been able to all but eliminate scratch making most of the gauges we
use. Depths for hole testing can be established by grinding a V ring around
the blanks at the proper depth on the "go" end. It's heartbreaking to spend
a lot of time on a scratch built gauge, then have someone drop it onto a
concrete floor.

RJ


--
James P Crombie
Slemon Park, PEI
Canada
Machinist - 3D Cad Design - Amateur Astronomer

http://www.jamescrombie.com

"Machineman" wrote in message
...
I find that if you are looking at anything under an inch in dia, then
pin gages are usually the easiest and cheapest route. They are available
in sizes from .004 to 1.0000 and in .0001 increments. The Travers
catalog gives prices at $8 to $15.50 each. Thats for the high tolerance
ones, the regular series are half the price.
A pin gage set comes in really handy around a shop. We used to fight
over them in the last shop I was at until I ordered another couple of
sets :-)

Backlash wrote:

I found making plug gauges of smaller diameters way too much work, so I
started making the handle out of 12L14 knurled to suit, drilled holes
into
each end, then crossdrilled and tapped for setscrews to hold appropriate
flatted pieces of either drill blank, or reamer blank. One of them is
supplied with plus tolerances, and the other is supplied with minus
tolerances. By choosing what I need, along with metric sizes available,
I
have been able to all but eliminate scratch making most of the gauges we
use. Depths for hole testing can be established by grinding a V ring
around
the blanks at the proper depth on the "go" end. It's heartbreaking to
spend
a lot of time on a scratch built gauge, then have someone drop it onto a
concrete floor.

RJ


--
James P Crombie
Slemon Park, PEI
Canada
Machinist - 3D Cad Design - Amateur Astronomer

http://www.jamescrombie.com


How any shop survives without at least a few sets of drill blanks is beyond
me. The are so useful that I have several sets of each, numbers, letters
and fractions. Drill (and reamer) blanks have to be one of the best
bargains available for the shop. They can be had from eBay for prices so
low that anyone can afford them. All my spare sets came from that source,
often for less than $20/set.

Harold

"Jeffrey Lindemuth" wrote in message
...
I am going to use a tool post grinder on my 9 inch star lathe. I picked up
a
Dunmore #14 at an auction recently. It is small, but taking lite passes
and
grinding between centers, I think think it will be OK. This is a hobby
project, time is not a major concern.
For lapping, I am planning to use cast iron laps and lap on the lathe, as
described in modern toolmaking methods (1915).
Just seems like a neat project.

If you set your compound rest to 6º clockwise past the z-axis (that is,
almost parallel with the ways the carriage slides on), each graduation on
the compound turns into a movement of 1/10 of the grad in the x-axis.

This means that if you dial in .001" on the compound rest, you will reduce
the *diameter* of the work piece by .0002".

Yes, for all of you with calculators it's actually something like 5.75º but
you don't need to be that picky.

I've had to turn (with a HSS cutter) 12L14 to a tolerance of +/-.008mm and
this method works quite well.

HTH.

Regards,

Robin

"Robin S." wrote in message
m...

"Jeffrey Lindemuth" wrote in message
...

If you set your compound rest to 6º clockwise past the z-axis (that is,
almost parallel with the ways the carriage slides on), each graduation on
the compound turns into a movement of 1/10 of the grad in the x-axis.

This means that if you dial in .001" on the compound rest, you will reduce
the *diameter* of the work piece by .0002".

Yes, for all of you with calculators it's actually something like 5.75º
but
you don't need to be that picky.

I've had to turn (with a HSS cutter) 12L14 to a tolerance of +/-.008mm and
this method works quite well.

HTH.

Regards,

Robin


I mount dial indicators to measure the actual movement of the cutter in the
radial direction. Then I do not need to measure angles and backlash is much
less of a problem. About a year ago I collected various Starrett .001 and
..0001 reading dial indicators from EBAY. It has proven to be a great
investment.

Jeff

"Robin S." wrote in message
m...

"Jeffrey Lindemuth" wrote in message
...
I am going to use a tool post grinder on my 9 inch star lathe. I picked
up
a
Dunmore #14 at an auction recently. It is small, but taking lite passes
and
grinding between centers, I think think it will be OK. This is a hobby
project, time is not a major concern.
For lapping, I am planning to use cast iron laps and lap on the lathe,
as
described in modern toolmaking methods (1915).
Just seems like a neat project.

If you set your compound rest to 6º clockwise past the z-axis (that is,
almost parallel with the ways the carriage slides on), each graduation on
the compound turns into a movement of 1/10 of the grad in the x-axis.

This means that if you dial in .001" on the compound rest, you will reduce
the *diameter* of the work piece by .0002".

Yes, for all of you with calculators it's actually something like 5.75º
but
you don't need to be that picky.

I've had to turn (with a HSS cutter) 12L14 to a tolerance of +/-.008mm and
this method works quite well.

HTH.

Regards,

Robin


Yeah, it works quite well until you have to rely on stops or marks such as
when approaching shoulders. Movement of the compound causes you to lose
location. It's far better to learn to work with the cross slide instead.
Yes, it is difficult, but certainly not impossible. I've done .0002"
tolerance work that way for years with good results.

Harold

In article , "Harold & Susan Vordos"
writes:

ow any shop survives without at least a few sets of drill blanks is beyond
me. The are so useful that I have several sets of each, numbers, letters
and fractions. Drill (and reamer) blanks have to be one of the best
bargains available for the shop. They can be had from eBay for prices so
low that anyone can afford them. All my spare sets came from that source,
often for less than $20/set.

Stupid question:
Has anyone ever tried to come up whith a more sensible set of sizes for drills
than numbers and letters?
If so how come it never went over?
Engineman1

"Engineman1" wrote in message
...
In article , "Harold & Susan Vordos"
writes:

ow any shop survives without at least a few sets of drill blanks is beyond
me. The are so useful that I have several sets of each, numbers, letters
and fractions. Drill (and reamer) blanks have to be one of the best
bargains available for the shop. They can be had from eBay for prices so
low that anyone can afford them. All my spare sets came from that source,
often for less than $20/set.

Stupid question:
Has anyone ever tried to come up whith a more sensible set of sizes for drills
than numbers and letters?

Ummm... yes.
Diameter expressed in millimetres (and decimal fractions thereof).

If so how come it never went over?

Works for me.

Engineman1

In article ,
Engineman1 wrote:

[ ... ]

Stupid question:
Has anyone ever tried to come up whith a more sensible set of sizes for drills
than numbers and letters?

How about metric? I've got sets of drills in 0.1mm steps from
1mm to 10mm. I use them in addition to the fractional, number, and
letter sizes to give more choices.

And I consider the number and letter drills to be intended to
fill the holes in the original fractional size sets, so you can get a
better size to drill holes to be tapped. The fractional sizes (in steps
of 1/64") are jumping something like 0.0156" per step, so there is a
need for smaller steps to fit various pitches of threads.

If so how come it never went over?

Because the extra sizes offered by whatever "rational" system
were simply absorbed as yet another way to get finer steps.

Probably, the most rational system (but a real pain to use)
would have each size 1% larger than the previous, as resistors area
available (also for coarser sets, 5%, 10%, and 20%).

An example, starting with 1 ohm, and 10% steps (a common set of
the carbon composition sets) would go (IIRC):

1.0
1.1
1.2
1.3
1.5
1.7
1.8
2.0
2.2
2.4
2.7
3.0
3.3
3.6
3.9
4.3
4.7
5.1
5.7
6.2
6.8
7.5
8.2
9.1
10.0

Note that the spacing in sizes grows with the size, which would work
find for finding reasonable tap drills for normal pitches, which also
get coarser with increasing size.

But -- it would still be a problem with extra-fine pitches.

1% increments wind up with really strange values, but they would
probably work nicely. Just pick some standard as the starting point,
e.g. 1.0", and use negative numbers for smaller, and positive for
larger.

And then, all you have to do is convince the world to re-tool
using your new system. :-)

Enjoy,
DoN.
--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

RESISTORS

1% resistors are the 96th root of 10 times the value before. To find
the 1% resistor value nearest to the value your calculator defines (1)
take the ln of the exact value (2) take the ln of the 96th root of 10
(3) divide the second number into the first. You will come out with a
number and a decimal. Throw the decimal away(NOT rounding,
discarding). Raise the 96th root of 10 to the whole number result of
the division. This operation will give you (after rounding to three
decimals) the 1% value below the exact number you sought. Multiplying
by the 96th root of 10 once more gives you the 1% value above the
exact number you sought.

Program this into your calculator if you work with resistors all the
time.