I decided to square up the flat bars before attempting to cut the 40º nose angles. Although very close and consistent, they still varied slightly.
I used a flat surface to to square up the factory ends and clamp two at a time then set them up for a face mill pass. I only have two shell mills and limited experience using them on steel. One is a four cutter that takes individual carbide tipped cutters that is manually indexed (3.5"), the second one is a 2.5" five cutter that uses TPG style inserts. Both of these cutter came with the mill as a package so not items I purchased individually with intent.
I had used the larger cutter on aluminum with very nice results and gave it a try. A face shield and long sleeve welding shirt became my best friends as hot chips where flying in all directions.
Here is the initial squaring using the factory edges prior to clamping. Poor mans granite surface
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Incidentally, I purchased the large set up block back in 2002-3 on eBay back when plenty of good deals could be had (not so much now).
I want to say I gave $20 for it and its flat. I use this on the press often when pressing smaller bearings.
Clamped the bars and set up on the mill.
The saw really did a fantastic job of cutting considering the length, but with a 12" cut they all had a slight .002-3" bevel that required clean up.
They will eventually be mounted in the vise flat for milling the steps on the ends. The sides need to be true for a good setup.
Verified the table and vise tram prior to this set up.
The backlight made it easy to verify the precision square to the factory edge.
No light showing after adjustment. Ready for the first pass. The right side on this particular piece was .001" wider than the left side (due to the bevel cut).
First pass using the larger shell mill at 700 RPM and 10 ipm (power feed) with a depth cut of .020"
Climb face milling, is this correct?
Re-clamped flipped and used the base of the vice for indexing the good side. A quick check with the square set up was satisfactory.
The carbide shell mill was tired starting off and the second cut finish looks like doo-doo compared to the first.
The second 6" pair of finger extensions where set up and I opted for the smaller 2.5" five cutter shell. This one uses TPG inserts that can be rotated three times. Well those where also tired from the start and had already been rotated three times. Poor planning on my part.
The finish was excellent compared to the second pass with the first cutter. All four 6" extensions are with in 1/2 thou.
I was able to get three of four sides of the 5" extensions before the finish surface began to diminish. The chips where glowing at 800 RPM and 10 ipm with a depth cut of .005" The inserts where done. Work stoppage until the new inserts arrive. I found some NOS Kennametal TPG 324 (1/16" radius) Grade KC730 (eBay). The old ones where unknown maker and more than likely a C2 grade. Inserts still confuse the hell out of me. It took me at least three hours to figure out what I had to begin with. Its all about learning, but inserts charts give me a headache
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Heres a shot of the finish.
The second shell cutter is a 2.5" ATP.
14 sides down (5" pair still on the mill ) and 12 to go.
Question for you experienced face mill users, would it be possible to utilize the same process to mill the the steps required, or will the interrupted cut be a problem for this type of cutter?
One end of top surface require a step. The opposing end gets the 40º angle cut (band saw).
The bottom gets both ends step cut. I have end mills but wondering if a face mill cut is appropriate.
That all the progress on the Dreis & Krump for now. Any advice is greatly appreciated. It's all about learning and not getting hurt.
Gonna take it easy today and take my wife to the Zoo for an evening special event.
Never been to our local Zoo at night so looking forward to seeing the nocturnal critters. Our evening temps are nice this time of year too.
Turn and Burn!
Paco
