Today I had the oppertunity to answer some questions about the Dream Cutter from a skeptical machinist, and I will share the response. The questions are omitted they are not ours to share, however I believe you will find the answers helpful in better understanding the Dream Cuter.
Thanks for the interest and probing questions. With these aggressive claims, the invention certainly deserves it! OK there are several misconceptions how the Dream Cutter unit is constructed and used that are apparent, certainly understandable with the limited information currently provided. I will address some of these now, and generate more examples later for the site.
First off its important to realize that the mini-lathe version is only the first line, one that is proven in prototype testing, yet due to its compact size presents the greatest challenges. The Mini-Lathe Dream Cutter as represented on the site now is optimized for miniature lathes. This must be considered so as to keep the potential for larger equipment in proper perspective. The claims will apply to all sizes of Dream Cutter, however the product lines will be optimized to take best advantage of the host lathe specifications. Later versions will be more massive, and require less hand manipulation, their look and operation will differ. We even have a servo-controlled version on the boards as well.
The Mini-Lathe Dream Cutter does perform well on its intended equipment (light, precision lathes of less that 7” swing) because we engineered the unit to match or exceed the typical mass of the mini-lathe’s parts and take advantage of unique aspects of the mini’s operation. While substantially more complex, the Mini-Lathe Dream Cutter is near the mass of the stock compound, and it is built with positive-lock (down) pivot adjustments and brake so that the assembly fits snug and pivots smooth. Its assembly is a highly engineered, jigsaw puzzle with precise and adjustable fittings. In other words, a key design requirement was to ensure that the Dream Cutter is NOT the weakest link in the chain. It does contain a leadscrew in both of its pivots.
The primary advantage and invention of the Dream Cutter technology is the incorporation of 2 additional degrees of controlled tool freedom of movement, rotational and transverse. I use the term “compound radial” to describe the primary and secondary adjustable pivot actions of the Dream Cutter as exhibited on a lathe cross-slide saddle, in place of the traditional compound rest. Think of a cutting arc whose azimuth intersects and tracks along an over arching arc. The essential purpose of having a secondary, adjustable tool post pivot, mounted on the arm of a primary adjustable pivot is for “Compound Radial Cutting”. A technique where material de-bulking is rapidly accomplished through radial side sweeps in advance of the final cut. In concert with aggressive plunges, this permits parting with significant reductions in tool stress. This side sweep reduces finish cut waviness, by leveling the cut trough. Waviness is a industry standard term for a measurable effect of surface finish on machined surfaces caused by the wake of the tool path as it cuts (melts) the workpiece surface.
This side sweep action does also facilitate radial part necking and piece parting with the ability to “nibble” through any thickness or material without chatter. You don’t even need a special parting tool as you can nibble to accommodate the tool dimensions as you part. Again your hand is on the upper control, and the operators body provides an extra layer of shock absorbing mass should a inadvertent bind or collision occur during the operation. Again an effect particular to a miniature equipment.
Another word on the rigidity of the Mini-Lathe Dream Cutter model, unlike larger versions it is important that the operator maintains control the tool (hands on the levers). This is essential during radial and taper to avoid collisions and to maximize rigidity and control of the pivot. The operator controls the tool post with his right hand, holding the secondary (upper) lever. Twisting this knob releases / brakes the tool post pivot. The primary pivot knob (lower) is used to control the primary pivot, with braking accomplished via the side lever. These brakes have a high degree of surface area and the assembly becomes more precise as they (positively) lock. The lever on the left of the tool post is used occasionally and has 2 purposes: 1) Quick tool release, 2) Locks the pivot offset.
I have some diagrams to describe this Compound Radial Cutting (CRC) technique that I will try to upload. With respect to the 3” ball claim, it is poorly worded. It should be “cuts a ball in seconds, up to 3”. Ie a 3” steel ball would take longer than a Delrin ball, however a small one can be accomplished in seconds with practice. It’s a very smooth, almost single action operation. The swarf this CRC method generates is enormous. The bass cuts fast, however yes a 3” dia steel ball would have to be cut carefully and much slower. HSS tools can do it though.
With respect to the video-demonstrations on the site, these are just preliminary and to demonstrate the concept employed. There are significant imperfections in this simulation representation with respect to movement, including distance pivot is offset. I had a difficult time making this from CAD. The actual max pivot offset is 3” for the MLDC (+- 1.5 from zero center). The idea with the taper demo is to show how in concert with the saddle, one can taper for the full length. The unit does have feed screws, in both axis. In actual prototype testing, I even applied a power screwdriver to the leadscrew knob to feed the plunge for a smooth taper cut. What I should have shown is how the unit can cut a taper in both directions, from either side of the work piece! Versatility and obstruction clearance is a prime advantage for a rest on a mini-lathe. This unit can taper the inside of a cup, and round the lip in a single operation.
With respect to operator skill, it can be used two ways. As a conventional compound or radius turner, its straight forward. With respect to Compound Radial Cutting, yes it requires two hands however the lathe X & Y are generally locked. The action comes quite natural and is fun. It may take some practice, however the artisans and craftsmen will quickly adapt. I have fun with the Mini-Lathe prototype all the time, however my mitts are large and I don’t grasp the lathe knobs well so I prefer to wield the Dream Cutter on my larger lathe.
Production units are on their way in August, just met with the CNC shop this morning. Since the initial (original) videos on youtube generated so much visibility, I am holding off showing more shots/videos of the prototype. I want to represent this new unit with its best image. The CNC versions with laser engraving are so much nicer than my hand cut assemblies.
We will make several units of the first batch available for evaluation and review, as it’s your all opinion not ours that counts.