Seco Crown Loc drills?

[wierdscience]

I have a repeat job that comes up at work that involves drilling a .725" diameter hole 3.00" deep in the end of a 1-1/2" diameter 1018 round bar that later gets reamed to .746 so it will shrink fit onto a 3/4" round shaft.

I've been drilling them in the lathe with a MT shank HSS drill.I would like to shave some time off that part of the process and was looking into carbide insert drills.Saw the Seco Crown Loc system and wondering if anyone has experience or could offer similar suggestions for insert drills.

No I will not be sending these out to a CNC shop and no there is no money in the cards for a CNC lathe so don't even go there

[George Bulliss]

Used them at a shop with very good results in the CNC mills. I can't remember the feedrates we used but it was way faster than using HSS, with no pecking required. They definitely need coolant blasting through them though, and at a pretty high pressure. I don't think they would last long at all without the coolant.

[KiddZimaHater]

Unfortunately, you will need through the spindle coolant for those type of drills.
We used the Kennametal indexable drills (Very similar) when making Cable-Stays for suspension bridges.
We were drilling .656 holes, 6 inches deep in 4130 steel at 1500 RPM and .015 feedrate. Straight drilling, no pecks.
Each block had 75 holes in a honeycomb pattern.
We would get about 150 - 200 holes before needing to change the insert.
But, again. We were using through the spindle coolant, blasting the chips out.

[wierdscience]

Okay,coolant shouldn't be that big a problem since I am already using oil hole drills and have a set up for them.Also have a 200psi coolant pump if I need it so it sounds doable.

Also looking at other options like carbide spade drills,any suggestions welcome.

[Ian B]

Never used (or even seen) the crown lock drills, but have used the carbide spade drills - often called 'U drills', and seen others use them far more intensively than I did. The ones I saw had a single replaceable tip. They were being used without coolant (I'm sure that using coolant would increase tip life and clear chips better, but chips seemed to come out fine).

Using these type of drills was a big a 'eureka moment' for me as was switching to carbide insert parting off tools.

Ian

[RussZHC]

Way, way past my "capabilities", but I did stay in a Holiday Inn......actually I read A LOT during my side tracked searches and I seemed to recall from that that the pressure you mention, 200psi is low.
I did find some very basic discussion and it seems as though there are at least two areas in general terms, one must be like Sandvik for example talking about 8 bar or a stream that sprays out 30cm without the spray "drooping" but there are others as well (a short thread on PM as example) where 1200 psi is given as a number. "Chipblaster" mentioned but not sure precisely what that is...

Sandvik had a technical paper even I got the gist of, lots of discussion revolving around best spent $$$ (or it is that reading between lines). Some things that I would certainly never have thought of such as actual angle (relative if the surface you are drilling into is not truly flat), whether or not it is the drill or the work that is revolving, difference in cycles, pecking and otherwise, in horizontal or vertical work. Given the $$$ involved, I would spend a bunch of time researching...that PM article did have a very little bit about finish comparing a couple of systems with SECO being one (forgot what the other was)

[Steamfixer]

Crownloc will make holes - no doubt. But You must have a rigid mill or lathe. Very rigid and in the mill it says max runout on the drill 0,06 mm or in the lathe the tip must not miss the lathes cl. with more than 0,03 mm.

Take a look at SECOs Perfomax SD505-19-95-50R-SC05 in the holemakinbook (page 160 in the 2008 Version)

The SECO-supervisor recomended Perfomax in stead of Crownloc because of the old mill and lathes lack of rigidty.

With the not so rigid mill in my shop the Perfomax made the holes asked for, a bit scary with all the odd noise. My mill doesent spin more than 1400 rpm so it doesent require cooling with SECO-tooling.

Ragnar, some strange spelling. :-)

[Steamfixer]

Oi, I see that with a 19mm Perfomax You are left with only 0,05 mm shrink fit. With Your 0.746" and 3/4" shaftdia You got a tenth of an mm.

Ragnar

[sawlog]

I am not familar with that drill, however the insert drills I used in the past on CNC lathes needed a lot of coolant. Also you need to pay close attention to the inserts. If a insert chips and you dont catch it you are looking at an expensive failure. I would go with the suggestion to use the carbide spade drills instead, especally if I was uning amanual lathe.