I need to cut an 18 degree surface. (18 degrees off horizontal.) Yes I
could block the part up on a sine bar, but I have to do it 4 times, and
two of those 18 degree surfaces butt right up against a shoulder that is perpendicular to the horizontal surface. If I had to make a bunch of
these parts I might call up Rogue Systems Inc, and ask if they would
make a custom mill for the job.

I'm having this crazy idea of making a D-bit or rather slightly less
than half D-bit with an 18 degree (144 degree include angle, but only
one leg of it) cutting lip on the face. Then use the tool to plunge a
hole (ream a predrilled hole) to get its effective cutting diameter
using an inside MIC. After making the tool then I could plug it into
CAM and tell it to cut an 18 degree slope from the bottom of the shoulder.

http://www.yumabassman.com/gallery/index.php/Bob-s-Workshop/IMG_20230422_142757369

I think by using this approach even if I am off several minutes on the
end cutting edge angle the total ripple of the surface will be a few
tenths. Well sans the capability of the machine of course. I could
probably check it with a protractor "close enough."

Using this approach starting at the shoulder (and maybe leaving the
grinder setup to resharpen each time) I should get a nice crisp sharp transition from the shoulder to the sloped surface.

The part is 3 pieces that fit together mating on the shoulder and the 18 degrees off horizontal faces. A wedge in a socket.

I can make the pieces with a square endmill and program an
excruciatingly small stepover, but it would take all day to cut the
sloped face that way. I was going to simulate in CAM and CAMOTICS then
do a time simulation, but it took to long just to just to calculate it
in CAM each time. I canceled the tool path calculation after 30 a long
time. I rebuilt a small carburetor and it still wasn't done.

I think I need to go clean and rebuild the next carb and think about
this for a little while.


--
Bob La Londe
CNC Molds N Stuff

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On 4/22/2023 2:37 PM, Bob La Londe wrote:

I need to cut an 18 degree surface.  (18 degrees off horizontal.)  Yes I could block the part up on a sine bar, but I have to do it 4 times, and
two of those 18 degree surfaces butt right up against a shoulder that is perpendicular to the horizontal surface.  If I had to make a bunch of
these parts I might call up Rogue Systems Inc, and ask if they would
make a custom mill for the job.

I'm having this crazy idea of making a D-bit or rather slightly less
than half D-bit with an 18 degree (144 degree include angle, but only
one leg of it) cutting lip on the face.  Then use the tool to plunge a
hole (ream a predrilled hole) to get its effective cutting diameter
using an inside MIC.  After making the tool then I could plug it into
CAM and tell it to cut an 18 degree slope from the bottom of the shoulder.

http://www.yumabassman.com/gallery/index.php/Bob-s-Workshop/IMG_20230422_142757369

I think by using this approach even if I am off several minutes on the
end cutting edge angle the total ripple of the surface will be a few tenths.  Well sans the capability of the machine of course.  I could probably check it with a protractor "close enough."

Using this approach starting at the shoulder (and maybe leaving the
grinder setup to resharpen each time) I should get a nice crisp sharp transition from the shoulder to the sloped surface.

The part is 3 pieces that fit together mating on the shoulder and the 18 degrees off horizontal faces.  A wedge in a socket.

I can make the pieces with a square endmill and program an
excruciatingly small stepover, but it would take all day to cut the
sloped face that way.  I was going to simulate in CAM and CAMOTICS then
do a time simulation, but it took to long just to just to calculate it
in CAM each time.  I canceled the tool path calculation after 30 a long time.  I rebuilt a small carburetor and it still wasn't done.

I think I need to go clean and rebuild the next carb and think about
this for a little while.

Ultimately I would also be able to cut all three parts in only 4 setups
with this home made cutter.

--
Bob La Londe
CNC Molds N Stuff


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On 4/22/2023 2:40 PM, Bob La Londe wrote:

On 4/22/2023 2:37 PM, Bob La Londe wrote:

I need to cut an 18 degree surface.  (18 degrees off horizontal.)  Yes
I could block the part up on a sine bar, but I have to do it 4 times,
and two of those 18 degree surfaces butt right up against a shoulder
that is perpendicular to the horizontal surface.  If I had to make a
bunch of these parts I might call up Rogue Systems Inc, and ask if
they would make a custom mill for the job.

I'm having this crazy idea of making a D-bit or rather slightly less
than half D-bit with an 18 degree (144 degree include angle, but only
one leg of it) cutting lip on the face.  Then use the tool to plunge a
hole (ream a predrilled hole) to get its effective cutting diameter
using an inside MIC.  After making the tool then I could plug it into
CAM and tell it to cut an 18 degree slope from the bottom of the
shoulder.

http://www.yumabassman.com/gallery/index.php/Bob-s-Workshop/IMG_20230422_142757369

I think by using this approach even if I am off several minutes on the
end cutting edge angle the total ripple of the surface will be a few
tenths.  Well sans the capability of the machine of course.  I could
probably check it with a protractor "close enough."

Using this approach starting at the shoulder (and maybe leaving the
grinder setup to resharpen each time) I should get a nice crisp sharp
transition from the shoulder to the sloped surface.

The part is 3 pieces that fit together mating on the shoulder and the
18 degrees off horizontal faces.  A wedge in a socket.

I can make the pieces with a square endmill and program an
excruciatingly small stepover, but it would take all day to cut the
sloped face that way.  I was going to simulate in CAM and CAMOTICS
then do a time simulation, but it took to long just to just to
calculate it in CAM each time.  I canceled the tool path calculation
after 30 a long time.  I rebuilt a small carburetor and it still
wasn't done.

I think I need to go clean and rebuild the next carb and think about
this for a little while.

Ultimately I would also be able to cut all three parts in only 4 setups
with this home made cutter.

Yes, I am aware there is a 4th piece in my sketch, but its just a
nominal machine to fit cap when the main stuff is done.

--
Bob La Londe
CNC Molds N Stuff


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"Bob La Londe" wrote in message news:u21k29$3e88m$1@dont-email.me...

I'm having this crazy idea of making a D-bit or rather slightly less
than half D-bit with an 18 degree (144 degree include angle, but only
one leg of it) cutting lip on the face.

-------------------

If you have a surface grinder and an end mill fixture of the type Snag is making, you can regrind a standard end mill to cut the 18 degree angle by clamping the fixture in a small insert vise. I used my fixture to grind the edges at the back relief tilt angle (like a drill bit) so the end mill could rough cut deeper with only the end edges, leaving the harder-to-sharpen side flutes sharp.
Like this: https://www.harveyperformance.com/in-the-loupe/drill-mills-drill-vs-mill/

Set up the angle with solid rods in the fixture and mill collets and 15 + 3 degree angle blocks between them. Rotate the end mill about 5 degrees off vertical to add back relief. I'd rough grind the end mill manually to reduce the amount the surface grinder has to remove. This is a good use for dull, chipped or undersized reground endmills.

Some of the thick steel in my scrap collection was flame-cut and has hard
spots unless annealed in the wood stove, which roughens the flat surfaces. I rough cut it in ways that allow easily resharpening the end mills, such as nibbling with plunge cuts, as there are no longer any nearby stocking industrial suppliers to buy new ones from, only a second-hand store that
sells used tools from auctions. They are usually high quality brand names,
but dull or damaged, so salvaging a few US endmills and large taps paid for
my surface grinder.

I do this with HSS because carbide tooling chips too easily on my 1960's machines. AFAIK it should work the same way with a diamond surface grinding wheel. I have only one and don't risk it experimenting.

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"Jim Wilkins" wrote in message news:u23emf$3r83k$1@dont-email.me...

15 + 3 degree angle blocks ...
------------------------------

I should mill an 18 degree angle block, it's close enough for carpentry purposes to the 4 in 12 slope of my roof.

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On 4/23/2023 7:44 AM, Jim Wilkins wrote:

"Jim Wilkins"  wrote in message news:u23emf$3r83k$1@dont-email.me...

15 + 3 degree angle blocks ...
------------------------------

I should mill an 18 degree angle block, it's close enough for carpentry purposes to the 4 in 12 slope of my roof.

I do have a surface grinder, but not an end mill sharpening jig. I also
do not have a diamond wheel for the surface grinder, and nearly all of
my end mills are carbide. I do have a diamond cup wheel and a diamond
cut off wheel for the D-bit grinder.

I also do have angle blocks, sine bars, and even a sine vise, but I have
found generally I get better results even with questionable methods if I
can cut a part in a single setup. I would prefer not to have to tilt
the pieces to orient the planes if I can find a work around like an 18
degree angled face cutter. Even with a single flute it will be much
faster than tens of thousands of incremental passes with a standard tool.

Remember my net time is my goal here. If I make an endmill jig, order a diamond wheel for the surface grinder (or buy some quality HSS mills to modify), and learn to grind end mills on the surface grinder it will
likely take longer than making a carbide tool on the D-Bit grinder. One
I pretty much have the stuff and already know how to make... more or
less. I'm still struggling with height settings the tool in the
machine. Creeping up on it really isn't a great option.

I've been saving my broken and worn out carbide mills for years. I made
other tools from some of them even before I had a d-bit or surface
grinder. Carbide ground to a cone makes a decent drag engraver and
holds up better than diamond tip tools that pop off when you hit any
slight irregularity. Anyway...

Your do have a good argument for adding a jig/fixture to my tools and
learning to use it at some point though.

--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist


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On 4/23/2023 7:44 AM, Jim Wilkins wrote:

"Jim Wilkins"  wrote in message news:u23emf$3r83k$1@dont-email.me...

15 + 3 degree angle blocks ...
------------------------------

I should mill an 18 degree angle block, it's close enough for carpentry purposes to the 4 in 12 slope of my roof.

I normally use bright uncoated 3 flute end mills: Preferentially. My
goal is good chip removal and decent material removal rate in the
aluminum most of my paying work is done. Of course I have other mills
for steel. Mostly AlTiN coated carbide 2 and 4 flute.

HOWEVER: Back when I was getting started I did a lot of work with what
other people "told me" was best. I bet I have some worn out and broken
2 flute uncoated end mills in the bottom of my bucket of broken carbide.
From back in the day... I bet I can use the T&C (D-Bit) grinder to
put an 18 degree chamfer cutting edge on the face of one faster than I
could cut a d-bit mill. A 3 flute or 4 flute would probably be more challenging for my skill level. With a 2 flute I can just get it dialed
in once, and use the 180 degree stops.

AND.. having two flutes I can feed it faster. It the point geometry is
a problem I can always grind off one flute completely and I will have a
fancy looking equivalent of the D bit I was going to make.

Well, this afternoon I either make the cutter, or I start setting up the
job with angle blocks.








--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist


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"Bob La Londe" wrote in message news:u26aam$dkol$1@dont-email.me...
...
AND.. having two flutes I can feed it faster. It the point geometry is
a problem I can always grind off one flute completely and I will have a
fancy looking equivalent of the D bit I was going to make.

-------------------

It doesn't need to be pointed or center cutting unless you intend to also
drill with it. The beveled tips on my 1/2" endmill are only about 0.1" wide, with the center sharpened normally. It's sized for the comfortable DOC of my Clausing mill in steel, specifically milling a wrench hex on threaded rod
which can rotate in the collet from high cutting force, not for cutting a
wide slope, for which the bevels could be wider at the cost of lower SFPM toward the center.

If you can change the angle to 18.435 degrees the Z rise will be 1/3 of the
X run, which might be easier to set up precisely.

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On 4/24/2023 10:34 AM, Jim Wilkins wrote:

"Bob La Londe"  wrote in message news:u26aam$dkol$1@dont-email.me...
...
AND.. having two flutes I can feed it faster.  It the point geometry is
a problem I can always grind off one flute completely and I will have a
fancy looking equivalent of the D bit I was going to make.

-------------------

It doesn't need to be pointed or center cutting unless you intend to
also drill with it. The beveled tips on my 1/2" endmill are only about
0.1" wide, with the center sharpened normally. It's sized for the
comfortable DOC of my Clausing mill in steel, specifically milling a
wrench hex on threaded rod which can rotate in the collet from high
cutting force, not for cutting a wide slope, for which the bevels could
be wider at the cost of lower SFPM toward the center.

If you can change the angle to 18.435 degrees the Z rise will be 1/3 of
the X run, which might be easier to set up precisely.

Sharpening to a point and then removing the point gives me the ability
to know how to set the tool height. Within a couple thousandths anyway.

--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist


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Pictures Posted Here: https://www.facebook.com/groups/MakersBuilders/permalink/1447879632416981/

If it works I'll let you know. Probably just have to listen to me bitch
about it if it doesn't.


--
Bob La Londe
CNC Molds N Stuff


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"Bob La Londe" wrote in message news:u3p9if$2ci73$1@dont-email.me...

Pictures Posted Here: https://www.facebook.com/groups/MakersBuilders/permalink/1447879632416981/

If it works I'll let you know. Probably just have to listen to me bitch
about it if it doesn't.

Bob La Londe
CNC Molds N Stuff
----------------------------

The item in the photo looks like a hose tee, or perhaps the pattern for
molding them. If it is, why 18 degrees?

I ask because I make odd-sized hose adapters fairly often, one last week.
I've gone away from sharp-edged barbs because in most cases I want to be
able to remove the hose without damaging it, for instance to drain and dry a gas tank for off-season storage.

I tried glycol-based CRC brake caliper grease on sticking valve O rings and
it freed them nicely, time will tell if it degrades them.

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On 5/14/2023 4:28 AM, Jim Wilkins wrote:

"Bob La Londe"  wrote in message news:u3p9if$2ci73$1@dont-email.me...

Pictures Posted Here: https://www.facebook.com/groups/MakersBuilders/permalink/1447879632416981/

If it works I'll let you know.  Probably just have to listen to me bitch about it if it doesn't.

Bob La Londe
CNC Molds N Stuff
----------------------------

The item in the photo looks like a hose tee, or perhaps the pattern for molding them. If it is, why 18 degrees?

Weird. If I click the link and it goes directly to a post with 3 images
of a "D-Bit" cutter.

Since you mentioned the T which is in a totally different post. Its s
3/16 1/8 3/16 reducing T. The only one I found was a plated brass one
on eBay for 24.50 shipped plus tax. The 1/8 inch leg didn't have any
type of barb or sealing ridge. I will probably leave the web behind the
barb effectively making it a round barb instead of a sharp barb. On
tube I do the same thing with a double flaring tool. It will get ear
type crimp on hose clamps so I think the seal will be just fine.

Yes I checked McMaster. I also checked auto parts sources. There is a
packet of misc vacuum fittings in the over priced "HELP" line of parts
that contains the correct size T, but I have not been able to confirm
the are gasoline safe, and that's what I used last time a few years ago rebuilding this stack of carburetors. It broke upon reassembly.

18 degrees has nothing to do with the T fitting. Its about the D-Bit
cutter.

I ask because I make odd-sized hose adapters fairly often, one last
week. I've gone away from sharp-edged barbs because in most cases I want
to be able to remove the hose without damaging it, for instance to drain
and dry a gas tank for off-season storage.

I tried glycol-based CRC brake caliper grease on sticking valve O rings
and it freed them nicely, time will tell if it degrades them.

--
Bob La Londe
Proffessional Hack, Hobbyist, Wannabe, Shade Tree, Button Pushing, Not a
real machinist


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