Question
We recently upgraded to a Biesse R30FT. With this new machine, we can push our tools faster and harder because of the increased hold-down power, but we've experienced tools slipping out from HSK cones/collets. A 1/2" upcut seems to be the main issue.
I was advised to take the 12-13mm collets and replace them with true 1/2" collets. The tool that has slipped (on more than one occasion) is a 1/2" upcut 3 fluted spiral chip breaker. Is this bit too aggressive or should we stick to a twin flute? Obviously, circumstances determine the tool needed, but some of this changes with the use of a flat table and spoil board. Our rates for the current tool that slipped were S18000, VF3 and a feed rate of 8. We were cutting solid 19mm maple and penetrating 17mm with one pass. We’ve also tried scuffing the shanks to remove the polish.
Any advice on tooling? I’ve had more success with up/downs, but they’re not the best choice when not fully penetrating.
Forum Responses
I have had trouble in the past with European collets having too large of an I.D. for 1/2" diameter tools. Also, collets wear out. I rarely have a tool slip, but when I do, I immediately throw out the collet and replace it with a new one. Most tooling companies will sell you proper sized collets for your type holder, at a decent price.
Just to review a couple of points about tool holders and collets:
1) Cleanliness is not optional, it is mandatory.
a) New tool holders will likely be coated with a protectant when you get them. You have to clean this off completely just before putting them into service. I use WD40 when I first remove them from the package to get the cosmoline(?) clean, then wash them down with alcohol. The alcohol leaves the tool holders clean and dry. Be sure you store them in a clean, dry place when not in use. If for extended period, be sure to hose them down with oil or WD or equivalent.
b) Changing tools: Completely disassemble the three components, and clean every one with a non-residual cleaner like alcohol. Do not use WD on the inside of the collet - WD and similar products attract and hold dust, while what you want is a clean, dry fit between the collet and tool shank. Technically, you should not use WD or equivalent on any mating surfaces in the tool-tool holder-spindle equation. I find that a little WD on the nosepiece threads and contact ring help ensure a good tightening, and protect against galling of the collet or nosepiece.
2) Collets are a wear item. The are subject to wear from normal use, and can be damaged in the case of tool breakage or dropping or improper torque - too little and the tool slips and degrades the inside of the collet, too much and you may damage it or the tool holder. Fortunately, there is an acceptable torque range. Collet style and tool holder nosepiece will dictate proper torque values.
3) Collets have two contact surfaces, both of which are critical to the proper mounting of the tool. The visible outside is what mates with the collet pocket in the tool holder, and must be free of dirt, debris, burrs, pieces of paper towel, etc. Rust is definitely not your friend here either. The inside of the collet is harder to deal with, but is probably the most abused. Acquire a selection of bore brushes (copper or brass work pretty well) and use those every time you change tools. An ultra sonic cleaner is on my wish list, but the object here is to make sure the bore of the collet is clean. If it is blackened with resin, you will not get a good grip on the tool and the tool with not run true. If you have a tool break off inside the bore of the collet, throw away the collet! If your tools regularly show little dark marks where the collet grips, you are having tool movement - this is not a good thing.
4.) Collets are designed to grip a tool shank, but not just 1/4” of the end of the shank. The best case is to have the tool shank long enough to be gripped along the entire grip-able length of the collet. In practice, if you get 75% of that, you're doing okay. If less, use a “collet buddy” or other plug at the rear of the collet to keep the grip surface parallel. The plug must be a precision piece. Follow the instructions on use and placement.
5.) Nosepiece. The collet and nosepiece are designed to snap together on the standard Biesse HSK tool holders (and every other tool holder I have ever seen except one, an ultra high precision, very high speed nosepiece, and I am fairly sure that nobody in the wood industry uses them). The Biesse tool holders that I have use an eccentric relief retainer in the nosepiece. You get the collet in by tipping it a little and pressing it into the nosepiece. It will “snap” in and then you can thread the nosepiece onto the body of the tool holder and insert tool, etc. I point out this last issue because many years ago, when I first had a collet and nosepiece (for an old Perske 5 or 7 hp collet spindle), I did not know about that snap-it-into-the-nut-before-you-tighten-it-up. That makes for a tough time getting the collet out of the spindle. It was several tool changes later when somebody educated me.
6) HSK63 tool holders, and HSK in general, is a very robust, rigid, axial constant repeatable tool system. However, it is also very finicky when it comes to cleanliness. Do not use WD or similar protectants on the cone or contact flange - use only the recommended dry protectant that Biesse (or your machine's manufacturer) recommends. The HSK system is sensitive to contaminants that get where they don’t belong, and compromise the otherwise excellent accuracy and rigidity of the system.
Summary: Clean everything every tool change - tool, collet, nosepiece and body. Every time. Use alcohol on mating surfaces, not WD. Use quality collets - the issue of on size collets can be argued as optional, but they will provide the best grip, and the better accuracy. Inspect tools for signs of collet wear - distinct “etching” like scallops on the shank of a carbide tool indicate slight movement of the tool in the collet - the more pronounced, the worse the condition. Onsrud publishes a very excellent article on collets and their care.
Heat shrink collets are available, but are pricey, and can only be used with carbide tooling. If you fit a steel-bodied tool into a heat shrink, you now have a permanent steel-bodied HSK tool. The heat shrink technology works on the simple principle of differing coefficients of expansion - as the tool holder is steel, the tool better be something with a lower Ce like carbide, or they will not be separable. This type is pretty neat, but a hydrolock seems more applicable to the wood/plastic/aluminum cutting we do on routers. I do not own any hydrolocks for the router, but I have been involved in their use on moulders. They are much better than slip bores, but when they fail, and they inevitably do, they tend to thrash things a bit more than a slip bore. I will defer any recommendations for or against the use of hydrolocks to those who actually use them. Ditto on the shrink fits.
Comment from contributor T:
I'm currently using shinkfit holders and will never go back to collets or even hydraulic holders. The increased rigidity is incredible. In machining aluminum I was able to increase feedrates twice of the corogrip and 3-4 times the regular collets. If you have a good unit, you can shink steel down to about 1/2" in diameter. Any smaller and it's permanent. If you are running high volume, it will more then pay for itself. HSK63 holders run $200-300 here in MI depending on length and diameter.
