Continuing the discussion from ISSUE: 3/8" end mill broken (Bridgeport):
Much like drill bits and other wear-items, the carbide inserts and end mills available for general use are sometime abused at DMS. If you really want to ensure that you have what you need to complete a project in the Machine Shop, some of our members have suggestions on the following items for your personal consumables kit.
I suggest purchasing your tools reconditioned from CDC Products in Richardson. They only take cash, and I believe are closed on Sunday’s and Monday’s. But they have great selection and prices and you get to physically SEE the tools.
I suggest starting with the following end mills.
0.5" 2-3 flute HSS center cutting end mill with a 1"-1.5" cutting length
0.25" 2-3 flue HSS center cutting end mill with a 0.75"-1" cutting length
There are many others that may be needed for some types of milling, but the above 2 will handle most of what you want. If you need to side mill a piece that is thicker then 1.5", try to find the largest diameter end mill you can afford that has the cutting length you need.
For the lathe, you just need to buy 0.625" sq HSS tool bits. Chiness HSS is fine for these. You grind the tool bit shapes you need.
CDC Products is where I bought my cleckos & clecko pliers many years ago. I love that place, unfortunately I forget they are there.
If you’re milling steel, I’d spend the extra money for carbide. HSS really can’t take much heat so your ops will take forever
Chris, I disagree. Carbide chips very easily (just look at all the carbide end mills in the shop), and is not really appropriate for the equipment at DMS.
Can you elaborate on carbide cutters being inappropriate for our equipment?
Carbide cutters are designed for speeds and feeds that the Bridgeport and the Colchester are really not capable of achieving. Particularly when operated by by inexperienced users. They are designed to maximize production in machine shops when operated by professional machinists.
They tend to need higher RPM and more aggressive feeds then our members should be attempting. This problem is compounded when they are used with intermittent cuts (which end mills ALWAYS are), since such shock forces easily cause chipping of the cutting edges. This can be dealt with when proper speeds and feeds are used; however, in manual machines that requires a skill few of our members can achieve. They reach their best use when being used on CNC equipment like the MultiCAM or the HAAS where there is no ‘machining’ skill involved, just programming and design skills.
CDC is awesome!! But as a small clarification, they don’t take credit cards. They do take cash or checks.
Why hasn’t anyone stepped forward for ceramic inserts - they take heat fantastic (good of 4000F) if machining nickel alloys (good of 4000F)… which we don’t do much of. 
Have longer wear life but our machines turn waaaaay to slow to make effective use of them.
Walter, care to comment on the difference between carbide cutters and carbide tipped cutters? I’m a fan of speeds n feeds so I believe there’s an application for both, but I haven’t been around long enough to know if our members understand the difference.
I am not a fan, and like solid carbide, I don’t believe they are appropriate for use in our manual tools. That said, here are some of the differences between solid carbide and carbide tipped.
I actually have ceramic insert holder and inserts for my Sherline (sold by Sherline). To date, I have never needed them for any of my projects, but some day!
Dropping a solid carbide or carbide tipped tool will pretty much guarantee it will shatter. Also not a good thing for us.
They’re expensive! The videos of them machining Inconel are impressive both in terms of removal rates and the temperatures achieved.
Apparently it’s more desirable as the high temps weaken the material ahead of the cut.
Because it can withstand higher temps it is able to be much more aggressive with material removal.
Another advantage, because of they way they are produced, they can really wild shapes/geometries when used on lathes they you really can’t grind into metal cutters. When I worked at a bearing factory we had special inserts that would cut a relief groove on the inside of bearing race that had compound radii and contours, all in one cut into tool steel.
You are right, for the casual machinist, they are not cheap. But in certain production environments they are super cost effective because they can avoid multiple cutters, do custom shapes, longer tool life and faster cuts. On mills I mostly saw them doing facing operations where the goal was to get it done fast on high Ni and Cr alloys.
As those of you who have taken my lathe classes know, I don’t think our carbide insert tooling is the best choice for our members. There only real advantage is that they don’t require learning the skill of grinding your own lathe tools from HSS tool bits.
BUT if you choose to do so (which I encourage) or decide to purchase holders for HSS inserts (which are more expensive then the Carbide inserts we use), then I suggest purchasing your own tool holders. This allows you to set the tool bit height and use a quick change tool post the way they are intended.
Our tool post uses BXA style holders, and you can purchase Chinese versions (which are what the space has) for as little and $18 each. Here is where I have purchased mine:
If you do nothing else, I suggest purchasing cut-off blades (HSS) suitable for use on a lathe our size.
Which can use blades like this; http://www.shars.com/products/cutting/tool-bits/p2n-p-type-hss-cut-off-blade
You can also purchase these cut off blades from CDC above.
Noob question here: Given that the old lathe may be going away, are these tool holders compatible with the new lathe?
Yes, these toolholders, and the spaces Quick Change tool post are style BXA, which means they are suitable for any lathe with a 12"-15" throw. The new lathe is basically the same size as the old lathe, so they should work fine.
Tool bit grinding is a pretty easy skill to learn on one’s own. Make sure you know the proper way to use a bench grinder (no pressure on the side of the wheel).
Here are a couple of good videos that describe the process
The angles are a bit different for the materials you intend to cut (steel, aluminum, and brass), but they aren’t terribly important. Most of these tools were hand ground, so variations in angle are fine. A 5/8" square of tool steel is cheap (<$10) and it will likely take you about 2 hours to grind your first tool. But it is well worth the effort, particularly for Brass…
