As some have said, I like having data, too. When I took the readout off my then pretty new lathe I replaced it with a laminated copy of the speed chart that tells me what the rpm is at any number on the speed pot (if I need to know). Now my data consists of a single number instead of the rpm. If anyone asks, I’m turning at 7. For the most part, I know where most blanks start off and where they are when they get round, but both are just the number on the dial. How the wood reacts to the spindle speed is much more important.
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Adding tachometer to lathe
- Thread starter Michael Anderson
- Start date
Exactly I have a tach on my lathe but I seldom look at it. How the piece reacts to the speed is more important.
With my P90 my intention is to add tachs to both the spindle and the motor shaft. Since I have both the reeves drive and the VFD I can play with the correlation between motor frequency/speed and spindle speed as it correlates to sheave diameter.
The purpose of this? Who knows? But I like to tinker and I like data. I am also still using the original 1959 motor on the lathe which will eventually fail and do so faster if I run it other than 60Hz. I should also be able to determine belt wear.
When it comes to actual turning… I have a piece of white athletic tape on the top edge of the dial for the reeves drive. It is easy to write on and erase with a pencil if I need to mark a position on it. ☺️
Oh, and I have a handheld laser tach with the contact attachments to measure surface speeds. Why blow all of my money on just wood and turning tools!
The purpose of this? Who knows? But I like to tinker and I like data. I am also still using the original 1959 motor on the lathe which will eventually fail and do so faster if I run it other than 60Hz. I should also be able to determine belt wear.
When it comes to actual turning… I have a piece of white athletic tape on the top edge of the dial for the reeves drive. It is easy to write on and erase with a pencil if I need to mark a position on it. ☺️
Oh, and I have a handheld laser tach with the contact attachments to measure surface speeds. Why blow all of my money on just wood and turning tools!
I used one from Amazon and added to my 2436. Find it very useful especially when teaching. Had a chart I made with a laser tach someone loaned me but a lot easier to read a display than look at a chart on the cupboard door. Have a PDF of a PPT I put together but too large to load. I initially used double sided tape for magnet but was not adequate and covered with a short piece of narrow fiberglass reinforced strapping tape. Emailed PDF to your email address at WoW.
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Roger Wiegand
Beta Tester
I've never had a lathe with a tach on it, so maybe I don't know what I'm missing. I love data, but it seems to me that the right data to worry about in this instance is how the tool and wood are interacting, unless, I suppose you are doing production turning with very uniform blanks. I fiddle with the speed quite a bit during various phases of turning, trying to keep track of what speed I used where would drive me crazy. I just go for fast enough, but not too fast.
For me the "what rpm are you running?" question multiple times during a demo is right up there with "do we have to know this for the exam?" in irritation quality, but then I tend to be grumpy. Everyone involved is probably happier that I stopped teaching pre-meds anyway.
For me the "what rpm are you running?" question multiple times during a demo is right up there with "do we have to know this for the exam?" in irritation quality, but then I tend to be grumpy. Everyone involved is probably happier that I stopped teaching pre-meds anyway.
Dave Landers
Beta Tester
As an individual turner, the RPM number is not really important to me. Like others, I rarely look.
But as a demonstrator/teacher/mentor I find it really valuable - for communication.
To say something like "the right speed for the wood" or "fast enough but not too fast" to another (especially new / inexperienced) turner is not helpful and IMO a bit insulting. I'd basically be saying "you should already know that" - but if they already knew they wouldn't ask.
The RPM number lets me say something that they can take home and duplicate, with little confusion.
On the flip side, if I ever try to learn thread chasing, that 300 or whatever RPM number is going to help me get that part initially right - at least until I find my own version of "oh, you know, the right speed".
But as a demonstrator/teacher/mentor I find it really valuable - for communication.
To say something like "the right speed for the wood" or "fast enough but not too fast" to another (especially new / inexperienced) turner is not helpful and IMO a bit insulting. I'd basically be saying "you should already know that" - but if they already knew they wouldn't ask.
The RPM number lets me say something that they can take home and duplicate, with little confusion.
On the flip side, if I ever try to learn thread chasing, that 300 or whatever RPM number is going to help me get that part initially right - at least until I find my own version of "oh, you know, the right speed".
To turn the debate around, why not a tach? Where is the harm in having this easily recordable and transferable data?
Does it shorten the life of the lathe? Too hard, technically for manufacturers? Lead to bad habits like glancing at the desired speed immediately prior to starting the machine?
We've gotten along without tilt-away tailstock for ever, don’t really need it, but folks like it.
Variable speed isn’t necessary, but we like it.
How about movable magnetic control pendant. I don’t have much use for it, but think it’s great that it’s offered.
So, the push back is interesting. It’s fascinating to me that second and third rate machines have tachs, but a few of the top rated do not. Inexpensive and desired by a significant portion of lathe users/purchasers, it would seem a no-brainer to add it.
There would be a Robust machine in my shop if it had the cool set-up standard on every Nova machine. Not cutting off my nose to spite my face. My Nova works well, but could be better, would like better.
Anyone remember the soup nazi on Seinfeld ? “No soup for you!”
Instead we have companies charging 10k for a machine, but “No Tach For You!!.
???
Does it shorten the life of the lathe? Too hard, technically for manufacturers? Lead to bad habits like glancing at the desired speed immediately prior to starting the machine?
We've gotten along without tilt-away tailstock for ever, don’t really need it, but folks like it.
Variable speed isn’t necessary, but we like it.
How about movable magnetic control pendant. I don’t have much use for it, but think it’s great that it’s offered.
So, the push back is interesting. It’s fascinating to me that second and third rate machines have tachs, but a few of the top rated do not. Inexpensive and desired by a significant portion of lathe users/purchasers, it would seem a no-brainer to add it.
There would be a Robust machine in my shop if it had the cool set-up standard on every Nova machine. Not cutting off my nose to spite my face. My Nova works well, but could be better, would like better.
Anyone remember the soup nazi on Seinfeld ? “No soup for you!”
Instead we have companies charging 10k for a machine, but “No Tach For You!!.
???
I primarily use the tac on my lathes to catch myself from turning bowls too fast. I also thread turn and I really like batching at the same rpm, it keeps me from double starting coarse threads... Eh, as frequently at least.
This is such a cool discussion, and is one of the reasons I like this forum so much. My question/need was answered/met a while back in the thread, but now we have a very interesting and relevant debate going on. I am enthralled. And, it reminds me of a phrase I’ve heard before (as most of no doubt have as well). If you ask 10 woodturners a question, you will receive 15 answers. Ha!
Really good stuff. Regarding the rpms, even IF the actual number isn’t prioritized, they can still represent a repeatable metric. Just like knowing how far to turn a dial, or what potentiometer readout you want to return to. Or, it can be an “in your face” reminder to make sure you speed is not up before you turn on your lathe for a new purpose. And sometimes it’s just a cool/interesting thing to know.
@Mike Brazeau thank you for sending that ppt. It never reached my email for some reason. I’ll look you up on WoW and touch base.
Really good stuff. Regarding the rpms, even IF the actual number isn’t prioritized, they can still represent a repeatable metric. Just like knowing how far to turn a dial, or what potentiometer readout you want to return to. Or, it can be an “in your face” reminder to make sure you speed is not up before you turn on your lathe for a new purpose. And sometimes it’s just a cool/interesting thing to know.
@Mike Brazeau thank you for sending that ppt. It never reached my email for some reason. I’ll look you up on WoW and touch base.
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I'm not against tachometers, but I wouldn't make a project of retrofitting one to a lathe lacking a tach. I want to keep to a safe speed range and I can get a pretty close idea from the potentiometer setting and then dial in the speed depending on perceived vibration. My Oneway has 3 graduated circles surrounding the pot dial which works for me. On my old lathe I did a quick mental calculation based on the pulley location and pot setting. I can see where some people would like a direct readout and it wouldn't be a stretch for manufacturers to offer one as do Nova and Vicmarc. Maybe the ones who don't are just set in their ways, as with Oneway's refusal to offer anything but an M33 spindle on their biggest lathe. Still, I'd rather have my Oneway 2436 w/o a tach than a Nova with one.
Roger Wiegand
Beta Tester
Well, that was intended mostly as a joke, not a useful comment to someone trying to learn. To a learner I would say something more like "lets start real slow, see how your tool bounces around over the imperfections in the wood, now turn the speed up some, see how the cutting gets smoother and easier to control? Now try even faster, and you see how the lathe starts to vibrate and the cut quality gets worse? Now try to go just a little faster to see if it's a resonance phenomenon that will go away with just a little change in speed. If it just gets worse, let's turn it down to where the vibration stops" and then go on to talking about how you need to turn small diameters faster and big diameters slower to present the wood to the tool at the same rate. And so on. I honestly believe that that will help the person to become a better turner than to just tell them to set it to 700 rpm.
I certainly don't object to the existence of tachometers on lathes, I just wouldn't pay money or go to any trouble to install one. Kind of like putting an altimeter on your lawnmower; doesn't do any harm, might be fun, but probably not terribly useful.
Check your Junk Mail. I did not get a bounce back. Sent some photos to my Notebook and resized and added. Last week I was shooting a few video clips with my iPhone and moved the Tach to the front of the lathe where I could see it as I played with the phone imaging. Magnets made it easy. I may take it to our Hands-On in a couple of weeks and mount temporarily o our General 260 as I am working on bowl turning with some newbies. I was 59 when I got my 2436 19 years ago. Brain does not work like it did then and another reason I appreciate the tachometer. Was a fun project too requiring some basic electricity knowledge!
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I see it now, thanks Mike. For some reason it was auto-filtered as spam. 
Not singling you out, Roger, I think this perhaps captures the opinion of the “no tachs”. I don’t disagree with demonstrating the advantage of higher rpm, or seeking a smooth rpm.
The issue I have is it doesnt provide a target range based on surface speed. Obviously a new blank needs to be started slowly and brought to an acceptable vibration point (which can vary by turner), roughed to better balance, speed increased, repeat as necessary, to where?
Cutting tools are designed to function in a surface speed range. The 6000/9000 rule works fairly well (and to every rule there are exceptions). Providing a target range prevents too much or too little speed - and again, the lathe cant be bouncing around the floor.
IMO its better to communicate a range, with vibration governing the eventual speed. For the 6000/9000 rule, 700 rpm would be an 8-1/2” bowl roughing speed, ~ 1000 rpm finishing upper limit.
Without a speed reference how does the new turner build a reference? What prevents some from going overboard and possibly creating a dangerous situation? Fear? What about when they turn on a different lathe?
BTW the dial on the AB’s I’ve seen are labeled, so if you reference the dial and belt position you are effectively using a tach. Same goes for other lathes if you looked up speed ranges for pulley positions and estimate speed by dial position. Perhaps the discussion should be no rpm reference (other than “feel”, no belt or dial knowledge) vs rpm reference/approximation.
Teaching high school students, they have to learn the arithmetic rule of "X,000 divided by the diameter in inches" in order to pass their safety test, but 3 of the 6 lathes we use don't have a rpm readout. When we start them out, on spindle projects, I tell them to start from the minimum speed and increase to the speed they feel is comfortable. Considering teenage boys, I assumed this would lead to ducking multiple flying objects every day, but not so. "Comfortable" turns out to be much slower than I would turn at. I can't recall more than twice in 10 years having to reduce the speed at which a student was turning. Frequently, I urge them to speed up a bit, as 'comfortable' tends to be sanding speed.
odie
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You really don't have to have a tach, but if I had one, I'd use it.
I came up with the above solution long before tachometers were a "thing" with woodturners.....and, it solves the issue I had with start/stop/start/stop/start/stop, and returning to the exact rpm repetitively.
-----odie-----
Tom Gall
TOTW Team
Odie, I know all lathes have slightly different controls but I assumed they all work similarly. I've turned on maybe half dozen different full-size and mini VS lathes and they all returned to the same speed automatically. My General has a speed dial (pot.) and a switch (Forward-Off (mid position)-Reverse). Approx. 10-12-2 o'clock. Never have to adjust the speed unless I want to. Of course it also has the main power On/Off to the lathe motor and inverter.
Many years ago I watched David Ellsworth demonstrating on a General lathe and he was using Main power switch to constantly turn the lathe on and off to check his work and talk to the audience. He complained how inconvenient that was because the switch was on the inverter box mounted low on the lathe. I don't think that power switch would have lasted a week in his shop!
odie
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Odie, I know all lathes have slightly different controls but I assumed they all work similarly. I've turned on maybe half dozen different full-size and mini VS lathes and they all returned to the same speed automatically. My General has a speed dial (pot.) and a switch (Forward-Off (mid position)-Reverse). Approx. 10-12-2 o'clock. Never have to adjust the speed unless I want to. Of course it also has the main power On/Off to the lathe motor and inverter.
Many years ago I watched David Ellsworth demonstrating on a General lathe and he was using Main power switch to constantly turn the lathe on and off to check his work and talk to the audience. He complained how inconvenient that was because the switch was on the inverter box mounted low on the lathe. I don't think that power switch would have lasted a week in his shop!
Hi Tom.....
It's my understanding that it's better to turn down the potentiometer (speed dial) each time you shut down with the brake. By also bringing the potentiometer back to zero, you can then gradually bring up the speed according to the requirements of the work you are performing. It sounds like you are keeping the potentiometer at the same setting when shutting down and then restarting. Since I am turning it back to zero each time, this is the inspiration for my magnet with the pointer.
My Minarik electronics incorporate what they call a "brake", and it occurred to me that maybe that might be the difference. The manual suggests shutting down with the brake. I am not familiar with, or have any experience with any other kinds of lathes, or electronics.
-----odie-----
Tom Gall
TOTW Team
Hi Tom.....
It's my understanding that it's better to turn down the potentiometer (speed dial) each time you shut down with the brake. I think that is only helpful when turning a large, unbalanced piece - it can override the braking and shut down the inverter. By also bringing the potentiometer back to zero, you can then gradually bring up the speed according to the requirements of the work you are performing. If you are already at a turning speed for the work it shouldn't matter. It sounds like you are keeping the potentiometer at the same setting when shutting down and then restarting. Yes. Since I am turning it back to zero each time, this is the inspiration for my magnet with the pointer. I understand that - but, I think that may be unnecessary.
My Minarik electronics incorporate what they call a "brake", and it occurred to me that maybe that might be the difference. I have a Minarik on my Vicmarc 100 mini lathe (DC motor) so I don't know if that makes a difference. It's not necessary to crank down the speed - just turn it off. The manual suggests shutting down with the brake. The brake(ing) should occur automatically when turning off without ramping down the speed dial (pot.) I am not familiar with, or have any experience with any other kinds of lathes, or electronics. Simple solution - try it out - with/without wood and at different speeds. You'll find out right away if it works with your lathe's electronics - it should. I think you will like it! I know - us old farts don't like change!!! - but I'm an older fart than you.
-----odie-----
odie
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Hello again Tom......
I have tried it out, and it does return to the same speed......however, if I want to change to any other speed in the interim, I still need a way to accurately return to the same speed without relying on keeping the potentiometer unchanged. For those who do have a tachometer, this would be the advantage of having one. For those of us who don't have a tachometer, there needs to be a way to return to the same speed repeatedly, even though the speed has been changed for another purpose. This is the advantage of my simple method of having a pointer attached to the potentiometer with a magnet. It eliminates the need for a tachometer, and speed changes can be performed in-between the need to use a specific speed setting, and the need to return to that same speed setting.
Bottom line, Tom.....Keeping the potentiometer at a set exact speed won't work for my methods of lathe turning, but it might be satisfactory for other turners.
I also firmly believe that manually raising the speed is superior to allowing the electronics to do it. In my case, this may be an over-reliance on my need to be totally "hands on" with all aspects of turning, but you yourself have admitted that some out-of-balance situations may influence the absolute need to manually raise the speed. Also, there are times when I am adjusting the speed during turning, to eliminate minute levels of vibration change, which in some cases, does occur after removing wood from a spinning bowl. When this does effect the ability of lathe tools to perform the best possible cut, then manually adjusting the speed is essential for this purpose.
As always, I make no claims that my methods of turning are universally best for any other turners.....but, they have certainly evolved to a systematic method of achieving the results I demand of myself....and, of my finished bowls.
-----odie-----
If you take the pot to 0 then turn the lathe off, you are likely not causing the braking function to actuate. With a heavy piece and dropping the pot quickly it may engage. As to it being better, not really. If the drive came with an e-brake, it is designed to handle the load. If you are more comfortable controlling it with the pot, that's just fine as well. A lot of very heavy use use of the e-brake over many years could eventually cause a heat related failure.
Clarification - on/off and speed ramping in this context only refers to returning to a speed you have already deemed appropriate, as in turning the lathe off to sharpen or something. It does not refer to starting up with a new unknown blank.
The vfd, and the parameter settings from the mfr, are designed to ramp the speed without overstressing the electronics. Slowly raising the pot to your mag pointer will put a bit less stress on the drive components, and possibly extend the life of some of those components, but is really only applicable for continuous heavy loads. For the type of items you typically turn, it really doesn't matter.
Your mag pointer is a great idea where a tach is not in use. Something you may consider is investing $20 or so in a hand held tach like I linked to (post 11) to check that your pot is not going goofy. Check it once a year or so, or if you suspect something. You could put ~3 marks to check it, and just compare over time that it hasn't changed. May not be necessary as I know you are "in tune" with your lathe and would likely notice if it changed much.
Tom Gall
TOTW Team
I understand, Odie. Your magnetic pointer is a nice idea that will work for the situations you mention. However, the original premise was about the start/stop/start/stop etc., and then returning to the same speed repeatably. The electronics will do that more accurately and easily than manually turning the dial. All that said, I might just add a magnetic pointer for those rare occasions it might come in handy!Hello again Tom......
I have tried it out, and it does return to the same speed......however, if I want to change to any other speed in the interim, I still need a way to accurately return to the same speed without relying on keeping the potentiometer unchanged. For those who do have a tachometer, this would be the advantage of having one. For those of us who don't have a tachometer, there needs to be a way to return to the same speed repeatedly, even though the speed has been changed for another purpose. This is the advantage of my simple method of having a pointer attached to the potentiometer with a magnet. It eliminates the need for a tachometer, and speed changes can be performed in-between the need to use a specific speed setting, and the need to return to that same speed setting.
Bottom line, Tom.....Keeping the potentiometer at a set exact speed won't work for my methods of lathe turning, but it might be satisfactory for other turners.
I also firmly believe that manually raising the speed is superior to allowing the electronics to do it. In my case, this may be an over-reliance on my need to be totally "hands on" with all aspects of turning, but you yourself have admitted that some out-of-balance situations may influence the absolute need to manually raise the speed. Also, there are times when I am adjusting the speed during turning, to eliminate minute levels of vibration change, which in some cases, does occur after removing wood from a spinning bowl. When this does effect the ability of lathe tools to perform the best possible cut, then manually adjusting the speed is essential for this purpose.
As always, I make no claims that my methods of turning are universally best for any other turners.....but, they have certainly evolved to a systematic method of achieving the results I demand of myself....and, of my finished bowls.
-----odie-----
odie
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I understand, Odie. Your magnetic pointer is a nice idea that will work for the situations you mention. However, the original premise was about the start/stop/start/stop etc., and then returning to the same speed repeatably. The electronics will do that more accurately and easily than manually turning the dial. All that said, I might just add a magnetic pointer for those rare occasions it might come in handy!
You guys are going to have to come to the understanding that others are not going to do what you feel is the logical thing to do. A great example of this is the reasoning for tool steels where the edge lasts longer. Who could argue with that.....right? I didn't.....until my illogical mind determined there was a method of improving my woodturning by doing what is opposite to main stream thinking. The same thing applies here with my magnetic pointer. In my own (supposedly) illogical way of seeing the advantages and disadvantages, I've come to conclusions that are based on thinking that others don't (or won't) understand.
The magnetic pointer works for me.......and it accomplishes the tasks I require of it. Those tasks may not be the same as for other turners......and, the results I am able to attain on the lathe, are my guide for establishing my beliefs.
-----odie-----
You could always use one of these — only $10!
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Just laying out facts about machinery @odie. You get to choose rational or irrational for your personal world - we all do.You guys are going to have to come to the understanding that others are not going to do what you feel is the logical thing to do. A great example of this is the reasoning for tool steels where the edge lasts longer. Who could argue with that.....right? I didn't.....until my illogical mind determined there was a method of improving my woodturning by doing what is opposite to main stream thinking. The same thing applies here with my magnetic pointer. In my own (supposedly) illogical way of seeing the advantages and disadvantages, I've come to conclusions that are based on thinking that others don't (or won't) understand.
The magnetic pointer works for me.......and it accomplishes the tasks I require of it. Those tasks may not be the same as for other turners......and, the results I am able to attain on the lathe, are my guide for establishing my beliefs.
-----odie-----
odie
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How about a handheld one? Pretty cheap on Amazon.
I did a 3 day class with Jimmy. I still hear him saying, “faster, faster.”
very handy. Certain things like Cole jaws have a max recommended rpm. My guy recently updated and upgraded my 3520a and added a tachometer. I like that I can use it when I want or not.
Simplest way is to use a handheld tach to calibrate your speed control knob. The handheld ones I have need a small piece of reflective tape stuck to somewhere on the spindle.
I know it's super cool to install a readout system, but how do you know the system is accurate?
The coolest would be to have a system that reads out in feet per minute (FPM) to give an actual indication of the cutting speed like some metal lathes have. When you're turning a large diameter at the outer edge you may have an appropriate rpm and cutting speed, but when the tool is near the center the rpm is the same and cutting speed will be way too slow. On CNC lathes this is known as constant surface speed, the rpm is constantly being adjusted as determined by the diameter the tool is at.
I know it's super cool to install a readout system, but how do you know the system is accurate?
The coolest would be to have a system that reads out in feet per minute (FPM) to give an actual indication of the cutting speed like some metal lathes have. When you're turning a large diameter at the outer edge you may have an appropriate rpm and cutting speed, but when the tool is near the center the rpm is the same and cutting speed will be way too slow. On CNC lathes this is known as constant surface speed, the rpm is constantly being adjusted as determined by the diameter the tool is at.
Wow—very cool. At least w a tach, if accurate, some data better than no data.
Just keep in mind that nature always sides with the hidden flaw. Stand to the side and increase speed slowly. This piece of koa is an example of several rapid disassembly events I have experienced hover the last 50 years or so. I managed to put it back together and sent it to a friend in Mililani, Oahu
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Well, a flashback.... In retrospect, if you do a bowl turning demo, some one always asks what your revs/rpms are. I have to stop and look. I think it was Eric Lofstrom who said some thing like "it is easier to get smooth cuts at faster speeds". From me, "turning at higher speeds makes accidents much more spectacular"! Turn at speeds you are comfortable with. I would expect that after you have been turning a while, you will check your speeds by feel rather than by the tach. Always stand out of the line of fire!
robo hippy
robo hippy
It all about reference. When I had a lathe where speed control position meant something (a reeves drive lathe), I used a hand tach to determine rpm at each setting, and had lines on my rpm vs dia chart so I knew about what speed for a given operation. I suspect those with potentiometer controls relate dial position (rpm) to the work on the lathe. The dial position on my DVR Nova lathe doesn’t mean anything, its for changing speed. I use the rpm readout to know where I am, and as a reference to past work.
I like to know what surface speed Im turning at, particularly for finish cuts.
I like to know what surface speed Im turning at, particularly for finish cuts.
Michael,
I bought one of the Amazon hand held and put the reflective tape on my AB's silver hand wheel and it reads it with no issue. I used it to get ideas of how fast the speed control was when set at the marked locations on the speed control. If you want to try it prior to buying I can bring it to Christmas party on Friday if you wish.
Thanks, Alan
I bought one of the Amazon hand held and put the reflective tape on my AB's silver hand wheel and it reads it with no issue. I used it to get ideas of how fast the speed control was when set at the marked locations on the speed control. If you want to try it prior to buying I can bring it to Christmas party on Friday if you wish.
Thanks, Alan
IMO opinion cutting speeds are very important issue in wood turning. Take a 14" wood bandsaw, from memory those run at about 3,000 FPM cutting speed.
Assuming 3,000 is a good speed that would mean a 12" diameter (one foot) object should be cut at about 950 rpm at the outer rim. At the 6" diameter the ideal rpm it should be 1,900 rpm and at the 3" diameter the rpm should be 4 times the 950 rpm. That would be way too fast for most wood. Because of the rpm limits of wood most turning are done at too low a cutting speed which I believe is a primary cause of tear outs. Also the tear outs are a function of lack of rigidity in the hand held tools.
It's not only the wood that puts and rpm limit on turning, chucks and collets have their limits too. Good quality metal lathe chucks will usually be stamped with an rpm limit. A 6" chuck might have an rpm limit of around 2,500 where they become dangerous and start losing their holding ability. Collets have substantially higher rpm limits.
I've argued on here a CNC lathe can get a better finish than the best turner because of the machine's tool rigidity and ability to vary rpm to be at the ideal cutting speed.
I read
I have read that at 1,000 RPM or less, a bowl that comes off the lathe will drop to the ground. Higher than that and it can fly. I don't aim to find out if this is true. I'll stay around 1,000 RPM on bowls.
I have read that at 1,000 RPM or less, a bowl that comes off the lathe will drop to the ground. Higher than that and it can fly. I don't aim to find out if this is true. I'll stay around 1,000 RPM on bowls.
I did the tach Randy Anderson linked to and it worked pretty well. I printed a box for it and I added a 9v battery too so it was self contained. But ... it wasn't accurate - 5 to 10% low. And It was set to average over 5 to 15 seconds I'm guessing so there's be a lag. It wouldn't be reading 0 RPM for a while after the spindle stopped. The lag as it gets up to speed was no problem though. I needed(?) it because my Record Power used the tach readout as the set point and not the current RPM. Drove me nuts cause I kept expecting it to say 0 for an indication it was stopped. I use it to check the Off state or if I think I could use more, or less speed. while cutting. or sanding.
I think it was Stuart Batty who made the comment that things under 1000 will drop to the ground and things over 1000 will go everywhere. With my experience, I would say a definite maybe. Spindles, probably true. Bowls would be more variable on explosions....
robo hippy
robo hippy