Saw Machine Taper RPM & Feed Rates

[scdiveteam]

Hi,

I recently posted my fruitful experience using a laser tachometer to calibrate my saw tapering machines. Below is a chart that may be useful to some that may not have DC motor vernier control and are using pulleys or gear ratios. With this data they can dial in the exacting gear ratios without having to extrapolate. (Please note that these numbers are based on flat ground saw blades and not a router set up.)

The linear travel rates are based on my lead screws that are 10 TPI.

Anyone who is interested in data for the butt tapering can PM me and I would be happy to share that info in the near future. At this time I do not have completed data as I have 13 cues in the queue that are at .020 over size awaiting inlays before final passes so I am at an impasse. I cut two plain janes to final dimension this weekend and got very good results but I need to do more sampling with different rpm to speed ratios before I can find the absolute optimum combo on the larger dia.

Note: The Hogging RMS finishes are not quite as perfect and have a little spiral to them as the lathe speeds need to be higher to attain the sufficient torque required to take a .070 pass based on the power curve ramping. I felt that this initial tapering process is not as critical and does not need to take as much time per pass as long as the wood is not burning or the motor is not stalling.

Rick G

Bludworth CNC tapering machine converted to a manual machine with half nut lead screw, E-Stop and DC Motors and controllers.

 

[cuesmith]

Just out of curiosity why did you convert the CNC shaft machine to a manual one. I've got a similar manual machine I'm getting ready to convert to CNC! It just seems to me that you're going backwards unless you had serious problems that you could not repair with the CNC, which frankly seems to me unlikely.

 

[scdiveteam]

Just out of curiosity why did you convert the CNC shaft machine to a manual one. I've got a similar manual machine I'm getting ready to convert to CNC! It just seems to me that you're going backwards unless you had serious problems that you could not repair with the CNC, which frankly seems to me unlikely.

Hi Sherm,

Leonards machine worked great and is engineered very good. My reasons to change had to do with process control simplification. Because the lead screw was uninterrupted, it had to travel back to the start position to take a second pass as I like to take all of my passes in one direction relative to the blade rotation. Having a CNC to do a variety of tapers on G-Code Files is not my thing. I make one taper geometry for my cues. If for some abstract reason I need to do something different, i can always use the Cue Monster but I kinda doubt I will ever want to.

By going to the DC motors and controllers, 1/2 nut lead screw and e-stop I am able to process a lot of shafts at the same dimension. I cut 26 shafts this morning and they all when from .900 to .890 and all I had to due was throw one in, slide the travel back to start, flip a switch hit the half nut. I matched the motors torque and horsepower specs to the process and my machine can run for hours at a time and the motors barely get warm, even when I am hogging initial taper with multiple passes.

When I am doing a lot of shaft processing, I can put one in the machine, set the dial, start it up, and walk away to do other things as the E-Stop turns off the machine and dust collector. When I get back to the machine, I simply put another shaft in, start it up and walk away. When I am done all of the shafts are the same. It just seems a lot easier to hand control the taper bar elevation dial indicator instead of working with Mach 3 and the computer for shafts.

My butt saw machine works the same way and I feel I can get a lot more work done in a shorter period of time. When I have a shaft or butt at a certain size I just throw in a unit and turn the elevation dial so the blade just touches as my datum and it is doing the job within seconds of me approaching the machine.

When I first started cutting my shafts we used our Cue Monster, then when to a lathe with a taper bar, then the Blud CNC and finally the manual machines with the 1/2 nut and the E-Stop. After developing years of experience with these machine methods, I truly feel the manual method is the best way to go for me because of ease and simplicity. It cost me quite a bit of time and money but I feel I made the right move in the evolution. I could have made quick change taper bars and used one machine for both butt and shafts but my whole shop is based on one machine for each operation except for basic lathe work.

Eliminating set ups saves a huge amount of time and makes for higher production efficiencies. When it is all said and none, you sell a cue for X amount of money. I want to make sure X cost me as little time as possible per operation so I can maximize my hourly pay.

Rick

Saw tapering machine set up with my compound taper butt geometry.

 

[Mr Hoppe]

I've seen the finish that Rick is getting with these feed/speed combos, and it's almost like a finish sanding, without the effort. I have also heard many on here complaining of the barber pole spiral that they have to sand out over the years, and this info could be very helpful to some out there. Rick, thanks for taking the time to share this information!