On Sat, 2012-10-13 at 18:20 -0400, Matthew Herd wrote: > I have an Atlas 7" shaper -- far superior to my 10" lathe. It's almost > exclusively made of cast iron, and quite sturdy. I enjoy using it to square > up workpieces as it is easy to use and sometimes programming MDI codes in the > mill just isn't worth the trouble for odd jobs. I have been working on some > iron castings, and they have a tough outer skin. The flycutter was driving > me mad, so I switched to the shaper. Much easier! > > As an aside, the viscosity of the Vactra #2 doesn't allow the clapper to move > perceptibly on all but the longest of strokes, especially in low speed. Low > is WAY faster on mine than the one in the video. I don't know about his > claim of slower feed for better surface finish, my experience is that tool > geometry has more to do with it than speed, but then again I have fairly > limited adjustments on that score! > > One of the key features of a shaper is its ability, with the right > attachments, to cut true generated involute profiles for gears. This is > possible with a mechanism, but is better accomplished with a CNC controlled > rotary axis. It offers the advantages of hobbing with a single point tool > instead. Entirely possible to make a gear of ANY number of teeth assuming > your single point tool has the correct pressure angle and tip radius for the > module/diametral pitch you are using. The tool is then a simple triangular > tool with radius, rather than an involute profile. Much easier to grind, and > could even be done on the bench grinder with a gauge of the proper angle, > just like threading tools! Great flexibility in prototyping gears, but with > the downside that generating the gears takes FAR longer than hobbing. > > As I see it, the shaper offers several advantages. 1) Ability to use HSS > tool bits to perform a wide range of jobs that milling machines could only do > with specialized tooling. I.e. dovetails, T-slots, and many others I can't > think of off hand. 2) Internal keyways/splines/etc, which mills are > basically unable to do without a 'shaper' attachment. 3) Generated profiles > can be readily obtained (i.e. gears, as mentioned previously) with simple > attachments. 4) As mentioned, surface finish is excellent. I haven't > perfected some of the tool geometries, but it can be nearly mirror without > much effort. > > Disadvantages are 1) Can't shape a blind slot unless you drill out the end of > it first, 2) can't shape a pocket, at least not easily, 3) time. The saying > goes "you can make anything with a shaper but money." > > I would like to (someday) build a CNC shaper w/ rotary axis on the table > specifically for shaping prototype gears, splines, etc. I wonder, though, > whether the idea of a rotary axis on the ram would be worthwhile. If you > define the tool's geometry and have a rotary axis on the table, would you > really need the CNC control of the top slide angle? The only problem with a > CNC shaper is that it requires a lot of adjustments (stroke length, stroke > position, top slide travel - if you have one, knee travel, cross travel, and > possibly rotary axis). If you can bear to automate them all, then writing > the code may be a bit tricky. If you can't, then you'd have make adjustments > between program segments. Not dissimilar from tool changes, I suppose. > > Matt
Hi all, I came very close to cnc-ing a shaper a few years ago. Take a look at the side profile of the forward breechblock for a Starr rifle. Ideal for a cnc'd shaper where Z (the tool) is locked to X (the cross-feed). I finally gave up about half-way thru the project when the demand went away. Part of this was driven by the realization that I could do most of it with a vmc and cleanup the last bit with a file. The original block still shows marks from the shaper tool. When horizontal mills became commonplace then a ground profile cutter would have been used. Dave Dave > ------------------------------------------------------------------------------ > Don't let slow site performance ruin your business. Deploy New Relic APM > Deploy New Relic app performance management and know exactly > what is happening inside your Ruby, Python, PHP, Java, and .NET app > Try New Relic at no cost today and get our sweet Data Nerd shirt too! > http://p.sf.net/sfu/newrelic-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_sfd2d_oct _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
