2018 Archive

[HarryJM]

So I stopped by a estate tag sale today and purchased a few items at 50% off as this was their last day. Two of the items were boxes of 3/8 x 3/8 x 3 1/8 C.L Cobal USA cutting tool blanks (total of 17 blanks for $15) which I figured would be good to practice cutting my own lathe bits. So just out of curiosity I found the same blanks on ebay for $70 for 2 of them. So what is the story with that price. Is there something about C.L bits that I am not aware of?

 

[BGHansen]

More eBay and Harbor Freight shopping. Picked up some small boring bars (6 mm and 7 mm diameter) that take CCMT 21 bits. Recall the boring bars being something like $6-$8 each. Picked up 20 inserts too for under $8 per 10.




Picked up a batch of 10 new Guhring 1/4" parabolic drills. Impulse buy for $31.


I have a 12-ton HF shop press and swapped out the hand-pump bottle jack for an air over hydraulic. The press has served me well over the years, but the design at the load points isn't the greatest. The bottle jack pushes up on a piece of tubular steel which in turn pushed down on the base of the jack which has the arbor on the bottom. Steel rods connect the bottle jack base to the top tubular reaction surface. The nuts on the rods had severely deformed the tubing, not to the point of pulling completely through, but I wasn't in the mood for any surprises. A better design would be a piece of plate or channel to carry the load from the middle of the square tubing to the sides.

I went the easier route and bought a 20-ton press. The 12-ton air over hydraulic is on the new press, so shouldn't be bending this one. I'll repurpose the angle from the 12-ton press and make a rolling rack for stock storage.

My 12-ton press


Bent tubing, curious that a 12-ton rated
press would get this bent up with the
a 12-ton bottle jack . . . Safety factor in the design?!?!



New 20-ton press with the 12-ton jack


Bruce

 

[GoceKU]

Today just before new year's eve i did little work on the dashboard for the Little Niva i'm fixing up, i did couple of coats of body filler then sending, but is starting to take shape.

Happy New Everyone!!!!!!!

 

[mattthemuppet2]

Picked up some small boring bars (6 mm and 7 mm diameter) that take CCMT 21 bits.

Bruce

Bruce, I'd suggest getting some CCGT inserts for those boring bars. They're a little more fragile but cut waaaaay easier than the CCMT inserts. On bars that small you'll get a lot of flex and chatter with CCMT inserts.

 

[PHPaul]

I bought tungstens, collets, collet bodies and stainless steel wire brushes to see if my old Miller DialArc HF still has the stuff to TIG aluminum.

I've been TIGing mild and stainless steel off and on for a while, but haven't messed with aluminum since I worked in the cannery lo those many years ago, and didn't do much of it then. Other guys in the shop were MUCH better at it.

I do some "fixit" stuff around town and have had several inquiries about welding aluminum. Seeing as I have the machine and the gas (straight Argon) I figured I could drop a Benjamin on consumables and see if I can get good enough at it to admit to it in public.

 

[BGHansen]

Bruce, I'd suggest getting some CCGT inserts for those boring bars. They're a little more fragile but cut waaaaay easier than the CCMT inserts. On bars that small you'll get a lot of flex and chatter with CCMT inserts.

Hi Matt,

Thanks for the tip. I'll look some up on eBay.

Just curious, what's the difference in the "G" vs. the "M"? According to my info, the first character (C) is for shape (80 deg. diamond in this case). The second character is relief angle (C in this case for 7 deg.). The third character is tolerance (G is tighter than M). The fourth character is hole style (40-60 deg single-sided countersink for T). I wouldn't have guessed that tolerance would make that much of a difference, but I'm up for trying and buying anything for the shop!

Best regards, Bruce

 

[Cadillac]

Bruce I also have some ccmt inserts and have found the ccgt inserts fit the same pocket. They are sharp with a positive rake. Work very good on aluminum. Can use for steel but keep depth of cuts under .005.

I’ve found that tcgt inserts also fit for a tcmt insert. Same thing very sharp and work very good.

Hope that helps some.

 

[mattthemuppet2]

Just curious, what's the difference in the "G" vs. the "M"?

M stands for molded, a rounded tougher but blunter edge. G stands for ground, a sharp edge that's also more fragile. Think honed HSS sharp, but without the impact resistance. The CCMT inserts will take a lot of abuse in steel, but leave a poor finish (on my small lathe at least). The CCGT inserts will leave a beautiful finish and can take a thou cut easily, but a stall or slightly overzealous feed with a decent DOC = chipped tip.