Path: ...!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Bob La Londe Newsgroups: rec.crafts.metalworking Subject: Re: Those Cheap Diamond Inserts Date: Tue, 20 Aug 2024 11:23:19 -0700 Organization: A noiseless patient Spider Lines: 126 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Tue, 20 Aug 2024 20:23:19 +0200 (CEST) Injection-Info: dont-email.me; posting-host="0ca82237ae88365f3399826eb3353e43"; logging-data="3664263"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX19O/GJPDB6ZdcJAel2/U8zu" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:YmlsrJ+S6Xme8hrCLX0zGqqL1D0= Content-Language: en-US X-Antivirus: AVG (VPS 240820-8, 8/20/2024), Outbound message X-Antivirus-Status: Clean In-Reply-To: Bytes: 7973 On 8/20/2024 8:48 AM, David Billington wrote: > On 20/08/2024 07:50, Charlie+ wrote: >> On Sun, 18 Aug 2024 17:02:31 -0700, Bob La Londe wrote >> as underneath : >> >>> On 7/30/2024 2:44 PM, Richard Smith wrote: >>>> Bob La Londe writes: >>>> >>>>> On 7/29/2024 11:38 PM, Richard Smith wrote: >>>>>> I heard diamond >>>>>> * works for Ali because it has no solubility for Carbon >>>>>> * does not work for irons/steels because the hard tool >>>>>> "disappears" by >>>>>>      solution into the iron >>>>>> ? >>>>> My apologies.  I didn't at all mean something like a PVD diamond >>>>> coating.  DCMT is a diamond shaped insert.  Typically your find them >>>>> coated with TiN, uncoated, and occasionally with TiAlN or AlTiN >>>>> coatings.  My point was these small geometry inserts that work so well >>>>> in under power under-rigid machines like the typical import 7-8 by >>>>> 10-16 mini lathe also work on a heavier machine.  If the big boy >>>>> inserts don't work these still do.  In this case I was cutting 304 >>>>> stainless steel. It improved the finish, didn't require sharpening, >>>>> had less heat input, and did the job much faster net elapsed time. >>>>> >>>>> FYI:  I do a fair amount of aluminum cutting, and generally I've found >>>>> bright sharp uncoated tools do the best job and have the best material >>>>> removal rate for me and leave a good finish.  Diamond was popular when >>>>> I first started cutting aluminum on machine tools, and more recently >>>>> ZrN has become the popular coating.  I've tried them and the simple >>>>> fact is a coated tool isn't as sharp.  They might work better for >>>>> larger tools on larger machines, but on middle weight machines with >>>>> limited horsepower (5 or less) a bright sharp uncoated tool works best >>>>> for me. For high speed flood coolant makes the tool last without chip >>>>> welding, but coatings do not.  On smaller tools horsepower isn't even >>>>> a factor as the tool can't take it anyway. >>>>> >>>>> >>>>> -- >>>>> Bob La Londe >>>>> CNC Molds N Stuff >>>> Thx for this detail. >>>> Interesting yes certainly. >>>> Sorry "got the wrong end of the stick". >>>> >>>> I used cutting insert tooling - aagh - 30 years ago. >>>> Vertical milling shell-cutter on steel. >>>> Did well - they'd never seen steel chip ejection like a chain-saw >>>> cutting timber.  Took a visit from the rep. who explained this is how >>>> the tooling is supposed to be used :-) >>>> Coated carbide inserts - coating the gold coloured one - a Ti >>>> nitride(?) >>>> coating - for this steel. >>> >>> Pushing it harder and harder.  As I once offended Jim a little (sorry >>> Jim) over... time is money.  Even if you are doing something for fun, >>> favor, self... time is still your most valuable nonrenewable resource. >>> >>> I needed to make another batch of stainless mold cores today.  (Stock >>> design that uses upto nine (9) 1.5in diameter cores to varY the size of >>> the casting.  That's 18 cuts to true them up after they come off the >>> saw. >>> >>> My new inserts arrived a few days ago ago, but I wantedif I could bump >>> up the speed a bit with that little hobby lathe size insert.  I had been >>> using at at 300 RPM in low gear.  That's a starting SFM of 117 if I have >>> done the math right.  I am sure there are folks pushing big turning >>> centers orders of magnitude faster, but this is after all only a bigger >>> import lathe.  Its still an import lathe, and while its relatively >>> heavy, its light for its size. >>> >>> Of course the SFM drops as the diameter is reduced.  Maybe I could go >>> faster if I cranked up the speed as I reduced the diameter, but this is >>> a single phase gear head lathe.  The motor just turns one speed.  The >>> time to stop it and change gears would eat up any time savings. >>> >>> Just for the heck of it I decided to see how much faster I could start. >>> At 460 RPM the insert was still doing fine.  Still using the same insert >>> I used when I started this thread.  I don't mean the same type.  I mean >>> the same insert.  That means the insert was hitting the outside of the >>> stock at 180 SFM.  The number doesn't sound much bigger, but the part >>> time was definitely faster. >>> >>> A couple ends with an intact insert at that speed and I decided to try >>> the last couple parts at 755 RPM.  296 SFM.  That was significantly >>> faster.  Part time was a lot shorter, and the insert still looks like >>> when I started.  (I'll look at under magnification later)  It wasn't so >>> fast that I had any issue keeping up, but it was fast enough I couldn't >>> do anything else, like move the stock in the saw to cut the next rough >>> blank. >>> >>> Now that I have spares I think next time I cut a batch of these cores I >>> am going to push it until I chip an insert to see just what they will >>> do. >>> >>> Please bare in mind that these are relatively light cuts.  The blanks >>> come off the saw at about 1.4" to 1.41" and get trued to 1.375". >>> >> Interesting thread Bob, thanks, is this example the type of tool you are >> talking about? Never come across the diamond tipped versions of inserts >> but my original machining in industry experience was in the 1960's! Only >> hobby level now.. >> https://www.ebay.co.uk/itm/115334715488?_nkw=diamond+inserts+carbide+lathe&itmmeta=01J5Q723XNA0GREWTN8RFZEQK2&hash=item1ada7c1860:g:YyUAAOSwUtJiUKWN&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKnC8gu8jBQODZUzjY6nfSpuZas%2FJzGcWIYLgG5EPfxVgG0wH1c4QdrYrUHqD4z98NSE8atbz28SHAAsTTB%2FvXsdw1KSXcN7%2Bx6cwyg%2FcKXwvDq3eEqXZbpx%2Bzxtc0f0%2Fp0BsyoIUtnlZlJQI86p6TyhETkaZsGuuwYw1Ayo2CHAORe6WE1WiaDElO8xogeQY1mItmsxVxjRLhavW15vEW5hMGkyR8srWzmxrGq4dX%2B9yZ23zhsDDiiDdifsQ%2Bk8r7IRPefZ9T%2FppdLbpKF%2FwpjM%7Ctkp%3ABk9SR_S-iOetZA >> It says for non ferrous but you are using on stainless without any red >> spark? Can they be touched up if/when the edge goes?  I know its only a >> single but looks uncheap to me!  C+ > > If you read Bob's post 30/7/2024 he clarifies he's not talking about > diamond tipped inserts but diamond shaped rhombic inserts. > That's true, but I did run across a reference (Stefan Gotteswinter video maybe) to an actual diamond attached to a tool. There are also coatings that are called diamond, although most are actually DLC "diamond like coatings." -- Bob La Londe CNC Molds N Stuff -- This email has been checked for viruses by AVG antivirus software. www.avg.com