Tormach Superfly Cutter On 1hp Machine?

[Groundhog]

Mike - my experience is that the Superfly usually gives a very good finish, even a reflective finish, but not a mirror finish. My experience is from making aluminum emblems with chrome-like finishes on a finely trammed (and nodded) cnc mill for a couple of years. The superfly finish will not approach the finish I need (or will any cutter I know of).

 

[mikey]

Mike - my experience is that the Superfly usually gives a very good finish, even a reflective finish, but not a mirror finish. My experience is from making aluminum emblems with chrome-like finishes on a finely trammed (and nodded) cnc mill for a couple of years. The superfly finish will not approach the finish I need (or will any cutter I know of).

I would agree with you. It gives a nice reflective finish but not a mirror finish ... le sigh. I think it can be better though. My column is out 0.0007" at the head elevation I used for my tests so I'll shim the vise up and see if that improves things. I am not willing to dedicate the rest of my life to tramming the round column any closer than it is right now, only to have it go out every time I move the head in Z.

To get real, none of this makes a lot of difference in the grand scheme of things. The Superfly cuts a clean, flat surface and will square a work piece just fine while producing a reasonable finish. I think it is worth the cost, especially if you use the TTS tooling system. Like you, my prior experience is a truly mirror finish but I'll live with the finish I get with a climb cut.

 

[wildo]

This is exactly the thread I was looking for. I bought a Superfly based on some of the comments here as well as other sources. What I didn't buy though is the inserts, knowing that they can be had much cheaper on ebay. That said, there's SO MANY different "models" of SEHT inserts and I don't know what I'm doing. I see Mike and Tom are using the Korloy SEHT1204AFFN-X83, H01 grade insert for aluminum, but what insert would you use for steel? I bought an extra tool holder so that I can have a dedicated aluminum setup and a dedicated steel setup. Any insert recommendation for steel would be appreciated!

 

[wildo]

Looking closer, it appears that the SEHT1204AFFN-X83 H01 is exactly the insert sold for aluminum work by Tormach. So perhaps the SEHT1204AFSN-X45 PC3500 that they sell for "general purpose" would be appropriate for steel work?

 

[mikey]

Looking closer, it appears that the SEHT1204AFFN-X83 H01 is exactly the insert sold for aluminum work by Tormach. So perhaps the SEHT1204AFSN-X45 PC3500 that they sell for "general purpose" would be appropriate for steel work?

Yup, that's what I'm using, Will. It actually works pretty good with steel. I tried it with and without coolant and got a better finish without coolant on mild steel. I need to experiment more with this but I like the Superfly, for the most part.

 

[wildo]

How much does the grade matter? I can find plenty of SEHT 1204AFSN-X45 inserts on ebay, but none of them are coated and for steel (or universal) PC[3,5]xxx grade. I found this chart in the Korloy catalog.

I don't know if a flycutter is intended to use "turning" tools (I seem to find lots of threads here indicating that the Superfly works well because it uses turning tools) or if it can also use "milling" or universal tools. But it seems like I'd want to find an insert with a grade of at least PC3xxx or PC5xxx for cutting steel. The PC5xxx would be more useful since it can also cut cast and stainless as well. How important is the cutting style (turning vs milling, the machine type identifier)? Or is this grade stuff not all that important at all?

Tormach is selling inserts for the Superfly as a grade PC3500, which would be a PVD coated insert specifically for steel, intended for milling, with high wear resistance (and potentially not so tough- whatever that means).

 

[mikey]

I'm just using the X45 grade. It seems to cut mild steel, stainless steel and tool steel quite well. To be honest, I normally don't worry too much about insert grades. Yes, yes, I know it matters but in a hobby shop that does very low production runs I don't think it is as important. I've run my own tests, for my own edification, on inserts for boring bars and cannot see much of a difference in performance between grades. In a job shop, grades can make a difference in insert life, especially at the speeds a modern machine will run at, but in a hobby shop with the relatively low speeds and short runs we use I don't think it matters that much. So, I buy the right insert but I look for the most reasonably priced grade of it. So far, this has worked out okay for me.

 

[wildo]

I'm also trying to understand this chart. I can find on the sandvik webpage that workpiece material groups are broken up into ISO P, K, S, M etc. But Sandvik uses Coromant Material Classification beyond that point, which they call "MC-codes." They give an example:

The code P1.2.Z.AN

P is the ISO-code for steel
1 is the material group unalloyed steel
2 is the material sub-group for carbon content >0.25% ≤0.55 % C
Z is the manufacturing process: forged/rolled/cold drawn
AN is the heat treatment, annealed, supplied with hardness values


Note specifically the periods, as well as the amount of columns. I'm not sure if Korloy's use of "P20" would be the same as Sandvik's use of something like "P.2.0" since I've never seen this stuff before. I'm not sure it's entirely off topic to discuss what material ISO codes mean- at least as it relates to choosing an insert for the Superfly.

[EDIT]- or maybe Sandvik would write something like "P20.x.x"
I can only find info online about steel being "P" stainless being "M" etc; I can't find any info about numbers after the material group designation.

 

[wildo]

Ah! Finally.... Thanks to Google Books, I found this in the book

Cutting Data for Turning of Steel
By Edmund Isakov

 

[wildo]

Ok- so to recap, the CVD vs PVD would be for moderate temperature chemical vapor deposition vs physical vapor deposition, the former being apparently good for high toughness and surface roughness resistance, and the later being particularly good at high temperature resistance and high speed machining impact resistance. This make sense then than Tormach would have chosen the PVD vs CVD. Perhaps the CVD might be the better option for the home gamer with an older (slower spindle) machine. That means we probably want an insert grade starting with NC.

From there, unless you want a dedicated tool per material type, it seems to me that a universal tool for steel, stainless, and cast is more economical. Therefore we'll want a "5" after the NC. Note that Korloy also has an NCM (as opposed to NC5) type tool. Other than a textual description for the use case (interrupted cuts, etc) it doesn't seem to define the M in the "Indication of Work" column on their grade code. Never the less, NC5xxx or NCMxxx is probably on our radar.

From there, the machining type column. Now I'm sure there is documentation somewhere about this, but as best as I can gather- turning means the work is spinning and milling means the tool is spinning. Perhaps that affects the tool geometry, but I can't find data on this. Since Tormach chose a milling type tool, I can only guess we want a milling type as well. So now we have NC53xx or NCM3xx.

I guess the ISO grade column would depend on the application. The Korloy catalog defines the three insert options up to this point:

I'm guessing that any NC53xx or NCM3xx would be an excellent choice for most machining tasks in the hobby shop, though perhaps the NC5350 or NCM335 might be the best option since a flycutter would naturally see an interrupted cut pretty much constantly. On top of that, the categorization states that higher designation numbers are for slower speeds and heavier feeds.

(And score. There's plenty of NCM335 inserts on ebay.)