Mystery Project...

Thanks. We're heading into the juicy humid weather. Wanted to hurry and get that over with.

So what do you want to see next; pedestal, taper blocks or switch back & forth?

Ray

WHOH Ray! That is beautiful!


Bernie
 
Caswell. Cheap, easy, good quality, no muss, no fuss, no deadly chemicals. Surface prep is everything. Sandblast first (not required) followed by a rinse with rubbing alcohol and blow dry. Handle parts with gloves as the smallest amount of skin oil will show up as fingerprints. Must use clean shop towels etc when handling. I use both the glossy sealer and matte sealer depending if the part is visible or not.

http://www.caswellplating.com/metal-finishing-solutions/black-oxide-kits.html


Ray

EDIT: PS: Forgot to mention. Use Distilled Water! -Not tap water.



Thanks. We're heading into the juicy humid weather. Wanted to hurry and get that over with.

So what do you want to see next; pedestal, taper blocks or switch back & forth?

Ray
 
Wow Ray looks great!!!! I do have a question/maybe helpful tid bid. But I was watching a knife making show on Discovery channel. (I forget the name of the show) Any hoo, He was heat treating a knife in a foil pouch, and in the pouch he put two small pieces of paper. He said that when the paper burns, away goes the oxygen. Dont know if that helps/hurts or anything. Just passing it along.

Chris
 
Much thanks Chris...

I'm using powdered charcoal with potassium nitrate which has the same effect. The potassium cooks off around 600 degrees and produces carbon monoxide which A) uses-up the oxygen and B) is carbon rich and saturates the metal.

The darn problem I had was not being able to seal the foil very well because the part was a little big to handle in this setup. Pretty sure I mentioned this before but, next time around, I'll fill the oven box with Argon and give it a refresh squirt every 10 minutes or so. One other fellow suggested using CO2 and indicates good results but even my meager chemistry background says that's reactive and in theory, should not work very well.

Ray


Wow Ray looks great!!!! I do have a question/maybe helpful tid bid. But I was watching a knife making show on Discovery channel. (I forget the name of the show) Any hoo, He was heat treating a knife in a foil pouch, and in the pouch he put two small pieces of paper. He said that when the paper burns, away goes the oxygen. Dont know if that helps/hurts or anything. Just passing it along.

Chris
 
Looks like we're going to make some blocks for the tapers first.
Here's a nice hunk of 4140 (or maybe it's 4145, I'll have to look at the receipt). This thing was probably milled in big honk'n horizontal mill. The tooling marks are darn near 1/8" apart and 1/16" deep. A big face grinding bit probably nibbled that thing to size in a few moments.

Blob of 4145.JPG

After cutting off a couple inches it gets milled to make it fairly square. The bars in the jaws are used to keep the piece from getting cockeyed when the jaws press as the initial geometry of the piece was a little off.
Milling.JPG

And here it is all nice with rainbow colors on four sides. It's pretty square now. I was running a 1" facing endmill, carbide inserts, 1900 RPM at about 20 thou depth and cranking the table about as fast as I could. Didn' bother with coolant, just a spritz of WD. The slight scuffs at the bottom are when the side of the cutter starts dropping off the edge of the piece and the inserts aren't being supported evenly. Purely cosmetic. You can't feel it; it's just an optical effect due to different spectral reflection. We're talking surface differences on the order of angstroms...
PrettyRainbowColors.JPG

Next, I'll put put it in the 4jaw, drill a hole and start working on the taper. I won't worry about precise positioning of the hole or even if it's perfectly straight. That will get fixed much later on... This piece will get heat treated and will need a couple passes of seemingly redundant operations. I'm just play'n around...

Ray

Blob of 4145.JPG Milling.JPG PrettyRainbowColors.JPG
 
Thanks. We're heading into the juicy humid weather. Wanted to hurry and get that over with.

So what do you want to see next; pedestal, taper blocks or switch back & forth?

Ray

Wow- switch back and forth sounds interesting!



Bernie
 
OK, the backyard deck is done so the turret project can resume.

First Pic... The block from earlier was carefully setup in the chuck. It's mounted with a 3/8" offset because I want a slight lip to overhang the plate. The block was set perfectly flat and checked ad-infinitum with a TDI lengthwise on all four sides. After that a hole was bored down the middle. In the photo, a travel indicator is setup at the left of the carriage and a TDI riding on the compound. We're setting up the angle for MT 3 taper which is 1.4377[SUP]o[/SUP]. I'm checking by running the carriage 1/2" (as measured by the travel indicator) and watching the deflection on the TDI. 1/2 x TAN 1.4377 is 0.0125" so, the compound angle is adjusted until the deflection reads that amount. This is a basic Rise-over-Run Tangent slope calculation... How much the needle rises when the carriage is run 1/2". I could have used 1" as the amount of travel but, the Tangent of 1.4377 is 0.025" and the TDI doesn't read that high so, 1/2" was used instead.

After a few adjustments, it was reading dead on. Not shown is the use of a boring bar to start making the taper. I'm just using the compound crank to move the bit in and out. A taper attachment would be a better choice but, it hasn't arrived yet. At the wide part of the taper, the diameter will ultimately be around .98" (around there, can't remember at the moment). For now, I just opened up the hole enough to see how things were looking.


Taper Setup.JPG


Next pic: I purchased a store-bought MT3 reamer set (I hope to make these in the future for other taper angles) and here, it's inserted in the hole with a little pressure from the TS ram and twisted a few times. This is just a spot check to see if the compound setup agrees with the store-bought taper cutter. BTW, the taper set has both a rough cut (shown) and fine-cut tool.

Taper Check.JPG

Third pic: Here you can see things are well in agreement. The reamer is shaving evenly on the inside of the hole. I'll go back to widening the hole with compound cuts to the desired diameter then, I'll clean-up the hole with the rough reamer. After that, the block will need a little milling and holes drilled/tapped -and then a heat treat to about 30 RC. BTW: The block is 4140 so it should harden nicely. Once it's treated, I'll need to touch-up the taper with the fine cut reamer.

Tapered Hole.JPG

Ray

Taper Check.JPG Taper Setup.JPG Tapered Hole.JPG
 
You are a talented man sir!! Do you get nervous with all of that hang out and no support?

Chris
 
I appreciate the kind words but guys like Bill, and the folks making knives are doing stuff that requires skill and creativity I also feel that CNC programming takes talent because you have to program a machine to do what humans do naturally and with the help of the sense of feel and sound... What I'm doing is basic stuff to hopefully give people ideas.

Anyhow... Nope, not worried one bit. If you felt it, you'd know its solid as the Rock of Gibraltar. It's not going anywhere and yes, I do give these things consideration and not take it for granted. I am paying extra close attention to where my fingers and hands are as those corners would make mince-meat out of me if we tango'd at high speed.



Ray

You are a talented man sir!! Do you get nervous with all of that hang out and no support?

Chris
 
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