tapering question

T

takeitdown

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I am tapering using a Porper model B using a straight router bit mounted vertically beside stock, have several questions about the best way to do it. Looking for explainations supporting your answers.

Should I run the pass to the left towards headstock? Does the bit having a cockwise rotation cut dictate which way it should be run or does it not matter?

Should I be running taper into a widening taper or away from it? Running from tge joint to the butt is what I see most, but see others going opposite that. I would like to end my cut at headstock to be at controls to shutoff when pass is done. I will eventually be setting up a stop switch at the end of the run which will be automatic.

When getting close to a final pass shouldn't the pin or insert be placed and then the piece turned using that? To do this I think I should be tapering with the joint end at headstock and then running to the right towards the tailstock. That leaves me tapering cutting towards a wider piece with the blade turning towards the wider stock.

What speed should the lathe be turning and powerfeed advancing to limit and chattering, probably the slower the better. Does towards wider stock help limit this toi?

All this may not matter with a razor sharp blade turning 5000 rpm making thin cuts ect. I suppose after the initial pass, the blade is cutting the same depth of wood on each sucessive pasd. I just wat to better understand what I should be doing and the rationale for it. Thanks.
 
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takeitdown said:
I am tapering using a Porper model B using a straight router bit mounted vertically beside stock, have several questions about the best way to do it. Looking for explainations supporting your answers.

Should I run the pass to the left towards headstock? Does the bit having a cockwise rotation cut dictate which way it should be run or does it not matter?

Should I be running taper into a widening taper or away from it? Running from tge joint to the butt is what I see most, but see others going opposite that. I would like to end my cut at headstock to be at controls to shutoff when pass is done. I will eventually be setting up a stop switch at the end of the run which will be automatic.

When getting close to a final pass shouldn't the pin or insert be placed and then the piece turned using that? To do this I think I should be tapering with the joint end at headstock and then running to the right towards the tailstock. That leaves me tapering cutting towards a wider piece with the blade turning towards the wider stock.

What speed should the lathe be turning and powerfeed advancing to limit and chattering, probably the slower the better. Does towards wider stock help limit this toi?

All this may not matter with a razor sharp blade turning 5000 rpm making thin cuts ect. I suppose after the initial pass, the blade is cutting the same depth of wood on each sucessive pasd. I just wat to better understand what I should be doing and the rationale for it. Thanks.
Click to expand...


I cut both ways but take the last few cuts from left to right. This conventional milling seems to give the smoothest finish and less tool push off.

The wide end is next to my head stock on both the butt and shaft.

I put the pin in the butt after the final cut. I drill and thread the shaft when the tip is about .600.

I spin the shaft or the butt about 200 rpm. I always run the router at full speed. (20.000 rpm) 3/4 by 3/4 straight bit with the router vertical. I feed at 12 imp for rough and slow down to about 8 ipm for finish cuts. It depends on your machine. Is everything tight and lubricated?? You must have a sharp router bit or it all goes to hell. Don't hold the shaft too tight.


Every machine setup will have a harmonic where feed rate, spinning speed, and router speed will tend to oscillate and cut a barber pole. You must be able to adjust 1 or all of them to a point out of the oscillation range in order to get a smooth cut.....

Kim
 
whammo57 said:
I cut both ways but take the last few cuts from left to right. This conventional milling seems to give the smoothest finish and less tool push off.

The wide end is next to my head stock on both the butt and shaft.

I put the pin in the butt after the final cut. I drill and thread the shaft when the tip is about .600.

I spin the shaft or the butt about 200 rpm. I always run the router at full speed. (20.000 rpm) 3/4 by 3/4 straight bit with the router vertical. I feed at 12 imp for rough and slow down to about 8 ipm for finish cuts. It depends on your machine. Is everything tight and lubricated?? You must have a sharp router bit or it all goes to hell. Don't hold the shaft too tight.


Every machine setup will have a harmonic where feed rate, spinning speed, and router speed will tend to oscillate and cut a barber pole. You must be able to adjust 1 or all of them to a point out of the oscillation range in order to get a smooth cut.....

Kim
Click to expand...

Awesome. That's great info Kim. Gonna be "attempting" my first ever taper in a few more weeks after getting some taper bars next week. This is all info I can base off of or at least gives me an idea for a starting point.

How do you get your lathe to spin as slow as 200rpm ?? The slowest mine goes is around 800-850rpm.

Also you mention the importance of a sharp bit. How often do you have to replace your router bits ??

How do you know what bit to use for what task ?? You mention a 3/4" straight bit but all (or mostly) I see for sale are 3 wing and 6 wing cutters, all of different diameters. How do you know what bit, what size bit, for doing what ?? The last thing I need to do is sling a bit off the router at 20, 000rpm because I'm using the wrong bit, lol.

Lee Casto
 
thanks

I see on the model B video they offset the left end of the taper bar at the left end using the nearest mount hole. This sets the bar back to make the joint end at he headstock. I didnt notice this until just now watching it again. In the Porper model B demostration video with the wide end at the tailstock and cut towards the headstock. For shafts they showed the joint at the headstock and cut to the right. With the taper bar set in.the center mount hole. Both cuts were towards the thinner end of the stock.

It makes sense for me to cut always cut towards the tailstock for butts or shafts. I am making a dust box that goes over the router mount and have just enough clearance to the headstock to safely start from there and run to the headstock where I have several inches of room to stop the router. Eventually I will make a stop switch that will shut everything down when activated at the end of the run.
 
Hi,

On my shaft machine I spin at 104 Rpm and travel at 30 inches in six minutes. When it is right the sound of the cut does not oscillate and is a smooth continuous buzz sound. Oscillation means the cue is bouncing on the cutter. Keep it slow find what is right for your set up. Buy a laser tachometer for 25.00 and experiment until you maximize your rig!

DC motors and variable controllers for those functions are the best way to get vernier control over the process. You also want the slightest amount of tail stock pressure possible to prevent shaft deflection in the middle. Just a hair too tight and the shaft will bounce in the middle.

Even when hog tapering it is important to due the six minute passes as it does not shock the wood as much the slower you travel.

Rick
 
takeitdown said:
I see on the model B video they offset the left end of the taper bar at the left end using the nearest mount hole. This sets the bar back to make the joint end at he headstock. I didnt notice this until just now watching it again. In the Porper model B demostration video with the wide end at the tailstock and cut towards the headstock. For shafts they showed the joint at the headstock and cut to the right. With the taper bar set in.the center mount hole. Both cuts were towards the thinner end of the stock.

It makes sense for me to cut always cut towards the tailstock for butts or shafts. I am making a dust box that goes over the router mount and have just enough clearance to the headstock to safely start from there and run to the headstock where I have several inches of room to stop the router. Eventually I will make a stop switch that will shut everything down when activated at the end of the run.
Click to expand...
You need to buy a few low grade dowels and start cutting and watch what happens to your cuts .
Then you will know what direction to cut .
 
I got it setup right now.

Have the right end of taper bar set in the hole towards the front. Went to the other end and have it in place so the butt taper track is at 0.21" wider of a cut on the butt end. This will let me get to 0.83-1.25...sizes that I think are about right for my taste. I made a pass on the 30" BEM stock I had worked on the other day that was setup opposite and took a 0.08" pass with the thick end of butt now at tailstock. It was the same as the other way...with 0.42" of difference in diameters over 30 inches.

Thanks guys. When I finish the dust box setup I will post pictures. It is going to be simple and perfect....should patent it! With dust collection in place I can get crazy turnibg down stock fo a few cues I have in mind. Plan on building 2 in an assembly line fashion, doing the same steps in succession on each cue to foster my learning.
 
Can a fresh 1/4 4 flute carbide end mill be used effectively for tapering on a Taig-based system? I don't have a router mount to allow me to use the side of an end mill yet. My router is a Porter 7399,so 1/4 shank is all it will hold. Tommy D.
 
Dirtbmw20 said:
Awesome. That's great info Kim. Gonna be "attempting" my first ever taper in a few more weeks after getting some taper bars next week. This is all info I can base off of or at least gives me an idea for a starting point.

How do you get your lathe to spin as slow as 200rpm ?? The slowest mine goes is around 800-850rpm.

Also you mention the importance of a sharp bit. How often do you have to replace your router bits ??

How do you know what bit to use for what task ?? You mention a 3/4" straight bit but all (or mostly) I see for sale are 3 wing and 6 wing cutters, all of different diameters. How do you know what bit, what size bit, for doing what ?? The last thing I need to do is sling a bit off the router at 20, 000rpm because I'm using the wrong bit, lol.

Lee Casto
Click to expand...


To slow down the speed on a hightower with a pennstate ind controller..... open the controller...... there are 3 adjustment pots..... first mark the present position of each one with a marker...... with the lathe running at its slowest speed... adj the pot next to the big capacitor..... just a little and you can slow it down.... you do lose a little torque but you don't need it when cutting with router... I have 3 of these controllers and I have done this to all 3 of them...

I sharpen my router bits with a diamond honing stick .... got it on ebay cheap.... youtube has instructions on sharpening router bits..... also get some "blade coat" spray to use on any cutters...it's made by bostik ... it really helps..... you should be able to get a month or 2 from a router bit with heavy use.... Every couple months I do change the bearings in the router because they get noisy and rough.........

the only bit I ever use for cutting shafts and butts is a 3/4 straight bit..... if you want, you can use most any 3 wing slot cutter and an arbor that fits them.....I got a rougher cut with the 3 wing cutters but others swear by them....... none tool of these sizes will ever fly off at 20,000rpm........ don't worry about it... run it at full speed............


Kim
 
I always cut downhill with my Porper Model B. I have had the taper bearing disengage before and turn a tapered butt into a nice straight walking stick. When you cut downhill (butt cap to joint pin), if the lock for the taper comes loose, you haven't damaged your workpeice.

I have had better luck with a good straight bit over the wing cutters. The slower the better for your RPM and travel speeds.
 
I've gotten super smooth results with 3 wing slot cutters on butts but my lathe's lowest speed is still too fast to get good results on shafts. Instead I am using the end of a straight bit for shafts. I'm not crazy about the finish, but at least I can sand that. Egg profiles don't sand out, which is what I was getting from the vibrations from using the side of everything else I owned. Maybe I'll mount a circular saw in place of my router. That should do wonders on my tailstock. For woods that want to fuzz, 'bottom up' machining tends to reduce the fuzzing. For wood that's looking for an excuse to chip out, 'top down' machining is a little more cost effective.
 
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