• Beware of Counterfeit Woodturning Tools (click here for details)
  • Johnathan Silwones is starting a new AAW chapter, Southern Alleghenies Woodturners, in Johnstown, PA. (click here for details)
  • Congratulations to Paul May for "Checkerboard (ver 3.0)" being selected as Turning of the Week for March 25, 2024 (click here for details)
  • Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.

Lathe bolted down

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
I was very apprehensive about bolting my new Stubby 1000 to the level concrete pad I made for her. But after turning for a few weeks, I understood why turners like Guilio Marcolongo, he has one too, told me to make sure that I bolted her down. I used threaded rods and concrete epoxy. Followed the instructions carefully, mainly blow and brush the dust a minimum of 4 times. Waited 72 hours, and today I roughed turned 6 big wet, Milo bowls. What a difference! The most stable lathe ever! I was worried that if I ever throw a big heavy unbalanced piece, not sure what to expect. I used to let my first lathe walk, then bring the speed down, well, maybe a little bit of exaggeration, but she did walk a few times. I was told that it's better to let a lathe walk. If not the force will have to eventually go somewhere, the spindle and shaft. What are your opinions on bolting down a lathe? Other than some of you might want the liberty to move the lathe around, for whatever reasons, to clean up, to turn outside on a nice day, etc.. I'm happy with where my lathe is, and for obvious reasons, I will never move her. Aloha
 

odie

TOTW Team
Joined
Dec 22, 2006
Messages
7,074
Likes
9,473
Location
Panning for Montana gold, with Betsy, the mule!
What are your opinions on bolting down a lathe? Other than some of you might want the liberty to move the lathe around.. Aloha

Hi Emiliano......

I can't give you a "before and after" observation of the advantages of bolting down a lathe are......because my Woodfast has been bolted down from day one, in two locations. My lathe, at a little over 500lbs is probably subject to out-of-balance conditions more than yours is. I can remember back then that I was influenced by the thinking that bolting down the lathe is advantageous.....and it probably has about the same advantages as other turners who simply add weight to their lathes.

I feel confident that bolting down the lathe is contributing to my ability to minimize the effects of any balance conditions that ultimately are between the cutting edge of your tools and the spinning wood.......BUT, of course, there are other considerations that can be dealt with that can also be extremely helpful in the pursuit of the best cleanest cut possible. There are things a turner can do that involves the specific properties of the tool he is using, how it's presented, and the coordination between his brain and his hands. Outside of those things, one very important aspect of this pursuit of perfection, is the harmonic interaction of the wood stock and its relationship to a specific RPM.

All of these things are contributing factors, but it's my opinion that bolting down the lathe, or adding weight is one thing a turner can do that has immediate positive results, in many cases, and ultimately expands the realm of what is possible......:D

-----odie-----
 
Joined
Jul 26, 2016
Messages
2,326
Likes
1,105
Location
Nebraska
When you bolt the machine solidly to the floor you are also changing the natural harmonic frequency of the machine as it becomes solidly attached to the floor.
This usually transfers a large amount of harmonic vibrations into the concrete floor mass reducing the potential of damaging vibrations to the machine. Like any
other machine with rotating parts you still have wear points and the ball bearings will fail over time or from abuse.
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
When you bolt the machine solidly to the floor you are also changing the natural harmonic frequency of the machine as it becomes solidly attached to the floor.
This usually transfers a large amount of harmonic vibrations into the concrete floor mass reducing the potential of damaging vibrations to the machine. Like any
other machine with rotating parts you still have wear points and the ball bearings will fail over time or from abuse.
SO glad to hear all these positive comments. Today, a friend was watching me rough turn some big Milo bowls. He said he could feel the vibrations on the cement floor, like harmonics...
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
My lathe has been bolted to the concrete floor using drop in anchors since 1996.

Sitting solidly, only the floor has flexed at one time with a too slow rotation of a large out of balance piece of wood, speed increase worked.View attachment 32190
Look at that chunk of wood!! Thanks for the comment.
 
Joined
Oct 16, 2007
Messages
316
Likes
52
Location
Fort Collins, CO.
I to have my lathe bolted to the floor ever since I purchased it. I have roughed out and cored thousands of bowls. My mentor also had his lathe bolted to the floor for over twenty hard use years. That lathe still has the original bearings in it. Personally I could never understand folks who say let it bounce around, no offense folks - just my thoughts. Seems to me that all that twisting and turning and jumping around would be harder on the equipment welds and bearings and etc than holding it still. One caveat an old machinist told me "If you want to be really careful put a 1/4" to 1/2" hard rubber under each foot prior to bolting it down". He claimed that would act as a shock absorber yet you're still set solid. Having said that I did not put the rubber underneath the feet of my Vicmarc, nor did Dan on his hard use Vicmarc.
 
Joined
Feb 6, 2010
Messages
2,959
Likes
1,905
Location
Brandon, MS
still. One caveat an old machinist told me "If you want to be really careful put a 1/4" to 1/2" hard rubber under each foot prior to bolting it down". .


I have The rubber under mine and not bolted down BUT the vibration from bouncing is much better.
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
I have The rubber under mine and not bolted down BUT the vibration from bouncing is much better.
The old now-defunct sugar plantation used to change large amounts of conveyor belts now and then. I got a few giant rolls to line up some of my horse stalls. I have that under the Union Graduate, and I have to say, it helps.
 
Joined
Mar 10, 2015
Messages
347
Likes
149
Location
Aurora, Ont, CA
Website
www.revolvingarts.ca
Bolting the lathe down was one of the best things I ever did. Mine is about 2000+ and it seeing starting to "walk" scared the %^&*( out of me.
So when I built the new shop, that was the first thing I did. However it was too low for me (6'3"). So I used two car jacks to get it up to the right height, then poured concrete footings, up and over the lathes feet.

The difference in stability was amazing.
 
Joined
Feb 26, 2019
Messages
1,814
Likes
1,415
Location
Lebanon, Missouri
Emiliano, your are correct in the assertion that bolting a lathe down increased the forces on the spindle shaft and bearings with out of balance rotation, however as many are stating the parts can take it.
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
Emiliano, your are correct in the assertion that bolting a lathe down increased the forces on the spindle shaft and bearings with out of balance rotation, however as many are stating the parts can take it.
So many positive comments! Thank you to all of you that have taken the time to comment. Aloha
 
Joined
Aug 14, 2007
Messages
5,435
Likes
2,792
Location
Eugene, OR
I haven't bolted one down yet. Not sure if I ever will get around to it... Not sure if I would trust the epoxied in bolts or not, as I did concrete work for 30 years. Main problem would be eventual failure of that joint because of the vibration. My preference would be some all thread rod, with a J type hook on the end, and set this into the concrete. There are probably some hurricane hold down type things available at some of the hardware stores. You would have to jack the lathe up and have the bolts through the feet before putting in the concrete pad. When concrete is set, maybe a week, but probably longer than a full day, a nut and washer under the foot, and another set on top of the foot. You could then level up the lathe and try an unbalanced piece on the lathe to fine tune the placement of all 4 feet. That seems to me to be the most difficult part of getting your lathe in place. If all 4 feet are spot on for leveling, that will greatly reduce vibration issues going up to the headstock spindle and bearings.

robo hippy
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
When I bought the concrete epoxy, I was told they watched a video about how to apply it and more. The company hooked up a hydraulic machine to a threaded rod. The concrete broke in pieces, came out out of the ground, but the epoxy did not fail. The rod had the epoxy intact. I dont know about long term.
 
Joined
Oct 13, 2016
Messages
1,053
Likes
1,463
Location
Rainy River District Ontario Canada
I did use both initially in London and later here in Atikokan the drop-in anchors, drilled the holes deep enough for them to sit below the surface, then used a driver to set them tight in place, after that the bold pulling up on the inner part will make that a very solid hold, it uses the concrete’s strength, not some plastic material, see picture.

The reason I used these drop-in anchors in the first place, was so nothing is sticking up above the floor if I was to remove the lathe for whatever reason, as for levelling, it is very easy to slide spacers under the feet as there is nothing in the way with the bolt removed, though with my lathe setup, the lathe is levelled on the I-beam stand I used, so floor evenes does not come into play.

drop-in anchor.jpg drop-in anchor use instruction.jpg
 
Joined
Mar 1, 2020
Messages
89
Likes
85
Location
Lebanon, TN
I need my lathe to be mobile so I can put it away when not in use. I've not turned anything heavy or large enough to cause walking or significant vibration.

If walking becomes an issue, the approach I would take is this. I would drill a couple of anchor holes and install inserts, similar to Leo's in the post above, flush with the floor. When the lathe is in use, I would screw large Eye bolts into the floor inserts and use ratchet straps to clamp the lathe in position. The straps would absorb some of the vibration that would get transferred from the lathe to the concrete anchors if it was directly bolted down.
 

Dennis J Gooding

Beta Tester
Beta Tester
Joined
Apr 10, 2010
Messages
824
Likes
732
Location
Grants Pass, Oregon
.,,,,,,,,,,,,,What are your opinions on bolting down a lathe? Other than some of you might want the liberty to move the lathe around, for whatever reasons, to clean up, to turn outside on a nice day, etc.. I'm happy with where my lathe is, and for obvious reasons, I will never move her. Aloha

Emiliano, as an engineer, I see no problem with bolting down a lathe that “walks” under unbalanced loads. First of all, the “walking” usually is sliding not hopping. It takes far less sideways force to slide the smooth steel feet of the lathe over smooth concrete than it takes upward force to lift the lathe off the concrete, yet the two forces are roughly equal for a spinning unbalanced work piece. I would regard operating at a speed and degree of unbalance that would produce hopping as dangerous and counter- productive. The anchor bolts normally would need to resist sliding.

I take issue with the concept that bolting a lathe to the floor will increase the load on the spindle bearings when turning an unbalanced piece. In fact, it may tend to increase the maximum load on the spindle. First of all, note that when an unbalanced work piece spins, the unbalanced component of the weight produces a net rotating centrifugal force outward from the spindle. When the rotating unbalanced component is in the upper half of its orbit and tending to lift the lathe upward, the lifting force on the spindle at any instant is that component of the centrifugal force that is directed upward, less the total weight of work piece. When the heavy side is in the lower half of its orbit, the downward force on the spindle at any instant is that component of the centrifugal force that is directed downward, plus the total weight of the work piece. Therefore, even if letting the lathe rise would reduce the spindle load when the unbalance point is in the upper half of its orbit, the larger load which occurs in the lower half of the orbit (larger by twice the weight of the work piece) would remain.

Furthermore, if the lathe lifts, depending on how high, hence how long is the flight time, it may crash back down just as the unbalanced point of the work piece reaches its lowest point (where the spindle load is largest). This would make the maximum force on the spindle even larger than if the lathe were bolted down.
 
Joined
Oct 15, 2015
Messages
157
Likes
285
Location
Smithville, MO
Emiliano,
I have not thought about bolting down my AB but I'm thinking about it now. If you really wanted to take one for the team, you could get a nice unbalanced piece on your lathe and see what maximum speed you can run the lathe. Then unbolt the lathe and turn it back on. This would give us a really good idea as a side by side comparison using the same set of circumstances. :D
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
Emiliano, as an engineer, I see no problem with bolting down a lathe that “walks” under unbalanced loads. First of all, the “walking” usually is sliding not hopping. It takes far less sideways force to slide the smooth steel feet of the lathe over smooth concrete than it takes upward force to lift the lathe off the concrete, yet the two forces are roughly equal for a spinning unbalanced work piece. I would regard operating at a speed and degree of unbalance that would produce hopping as dangerous and counter- productive. The anchor bolts normally would need to resist sliding.

I take issue with the concept that bolting a lathe to the floor will increase the load on the spindle bearings when turning an unbalanced piece. In fact, it may tend to increase the maximum load on the spindle. First of all, note that when an unbalanced work piece spins, the unbalanced component of the weight produces a net rotating centrifugal force outward from the spindle. When the rotating unbalanced component is in the upper half of its orbit and tending to lift the lathe upward, the lifting force on the spindle at any instant is that component of the centrifugal force that is directed upward, less the total weight of work piece. When the heavy side is in the lower half of its orbit, the downward force on the spindle at any instant is that component of the centrifugal force that is directed downward, plus the total weight of the work piece. Therefore, even if letting the lathe rise would reduce the spindle load when the unbalance point is in the upper half of its orbit, the larger load which occurs in the lower half of the orbit (larger by twice the weight of the work piece) would remain.

Furthermore, if the lathe lifts, depending on how high, hence how long is the flight time, it may crash back down just as the unbalanced point of the work piece reaches its lowest point (where the spindle load is largest). This would make the maximum force on the spindle even larger than if the lathe were bolted down.
The perfect explanation! Thank you, you made my day! Appreciate you taking the time to comment. Aloha
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
I need my lathe to be mobile so I can put it away when not in use. I've not turned anything heavy or large enough to cause walking or significant vibration.

If walking becomes an issue, the approach I would take is this. I would drill a couple of anchor holes and install inserts, similar to Leo's in the post above, flush with the floor. When the lathe is in use, I would screw large Eye bolts into the floor inserts and use ratchet straps to clamp the lathe in position. The straps would absorb some of the vibration that would get transferred from the lathe to the concrete anchors if it was directly bolted down.
Not sure if that would work...
 
Joined
Mar 1, 2020
Messages
89
Likes
85
Location
Lebanon, TN
I transport my motorcycles pretty much using this strap principle. Four anchor points in the floor would be ideal, triangulating the straps from the lathe. Imagine where the straps go around the frame was a point on the lathe and the trailer attachment points are where eye bolts would be anchored in the floor. Do this on both ends and it's not going anywhere.

GLTieDown3_zps1c1e1c59.jpg
 
Joined
Jul 10, 2017
Messages
824
Likes
665
Location
Windermere, British Columbia
Emiliano, your are correct in the assertion that bolting a lathe down increased the forces on the spindle shaft and bearings with out of balance rotation, however as many are stating the parts can take it.
I don’t think this is right. I think there are more loads and forces on spindle if lathe is allowed to jump or move around. The spindle is bring jarred etc on each hop. If bolted down the forces are transferred into the floor and the spindle does not get that jarring , so less damage to lathe.

think of driving down a bumpy gravel road. You have a box in the back allowed to bounce up and down. Guaranteed something will be broke. Now tie the box down and drive the same road. Do damage.
 

Dennis J Gooding

Beta Tester
Beta Tester
Joined
Apr 10, 2010
Messages
824
Likes
732
Location
Grants Pass, Oregon
The perfect explanation! Thank you, you made my day! Appreciate you taking the time to comment. Aloha

Emiliano, here is one more reason to bolt down a lathe if it tends to “walk”. It relates to the three-legged versus four-legged stool phenomenon: A three-legged stool is always stable whereas a four-legged stool is rarely stable on typical floors. If the lathe feet are perfectly adjusted for a given position on a typical concrete shop floor, the adjustments may not be correct when the lathe walks even a few inches. It is important that all four feet be in firm contact with the concrete; otherwise, an unbalanced work piece may cause a rocking motion about the two diagonally situated legs that are firmly in contact with the floor. Some use an elastic pad under the legs to take up any slack. In my opinion, this should be used with care. If the pad is too thick or too yielding, it may make the problem worse. In any case, it would not be as effective as bolting the feet down firmly, shimming as necessary for fit.
 

Emiliano Achaval

Administrator
Staff member
Beta Tester
TOTW Team
Joined
Dec 14, 2015
Messages
3,307
Likes
4,226
Location
Maui, Hawaii
Website
hawaiiankoaturner.com
Emiliano, here is one more reason to bolt down a lathe if it tends to “walk”. It relates to the three-legged versus four-legged stool phenomenon: A three-legged stool is always stable whereas a four-legged stool is rarely stable on typical floors. If the lathe feet are perfectly adjusted for a given position on a typical concrete shop floor, the adjustments may not be correct when the lathe walks even a few inches. It is important that all four feet be in firm contact with the concrete; otherwise, an unbalanced work piece may cause a rocking motion about the two diagonally situated legs that are firmly in contact with the floor. Some use an elastic pad under the legs to take up any slack. In my opinion, this should be used with care. If the pad is too thick or too yielding, it may make the problem worse. In any case, it would not be as effective as bolting the feet down firmly, shimming as necessary for fit.
If you ever make it to Maui, please stop by, we will have some fun in the shop. I really like your explanations. Thank you for such a detailed response. Aloha
 
Joined
Jan 8, 2020
Messages
189
Likes
52
Location
Bloomfield, New Jersey
Emiliano,
I have not thought about bolting down my AB but I'm thinking about it now. If you really wanted to take one for the team, you could get a nice unbalanced piece on your lathe and see what maximum speed you can run the lathe. Then unbolt the lathe and turn it back on. This would give us a really good idea as a side by side comparison using the same set of circumstances. :D


We need video, too ;-)
 

Dennis J Gooding

Beta Tester
Beta Tester
Joined
Apr 10, 2010
Messages
824
Likes
732
Location
Grants Pass, Oregon
Not to belabor the issue, but I think it is instructive to consider the size of the forces involved here. As a first example, consider a moderately large semi-circular green wood bowl blank that is 16 inches in diameter and 8 inches deep. Assuming that it a typical green wood that just floats or almost floats in water, it would weigh about 40 pounds. Further, assume that there is some aberration in the density or exact shape of the piece that it is unbalanced in a way that is equivalent to adding a 1.0 pound weight (2.5 % of the weight of the bowl) centered a point on the outer rim of the bowl. Now suppose the bowl is spun at 500 RPM. Reference to any of several on-line calculators reveals that the centrifugal force acting on the spindle is about 57 pounds—more than the weight of the bowl. Similarly, doubling the speed to 1000 RPM would result in a centrifugal force of about 227 pounds.

As a second example consider a bowl blank 40 inches in diameter and 20 inches deep (a challenge for Emiliano’s new Stubby 1000). Under the same assumption as above, it would weigh about 600 pounds. Assume the same 2.5% unbalance centered at a point on the outer rim as before. At a speed of 200 RPM the calculated centrifugal force is 340 pounds. Doubling the speed to 400 RPM increases it to 1360 pounds.

The moral here is “balance the bowl blank as well as possible before turning on power and keep the speed way down”.
 
Joined
Jul 26, 2016
Messages
2,326
Likes
1,105
Location
Nebraska
Take one of the wheel weights off of your vehicle and drive it down the highway at a high rate of speed and you will quickly see what an ounce of weight being out of balance can do to your vehicle while driving down the road. Enough out of balance weight and the tire will start bouncing off the surface of the road as your shock goes into overdrive trying to counter the action of the out of balance wheel.
 
Joined
Jun 30, 2008
Messages
172
Likes
212
Location
Chatham, Ont.
Not to belabor the issue, but I think it is instructive to consider the size of the forces involved here. As a first example, consider a moderately large semi-circular green wood bowl blank that is 16 inches in diameter and 8 inches deep. Assuming that it a typical green wood that just floats or almost floats in water, it would weigh about 40 pounds. Further, assume that there is some aberration in the density or exact shape of the piece that it is unbalanced in a way that is equivalent to adding a 1.0 pound weight (2.5 % of the weight of the bowl) centered a point on the outer rim of the bowl. Now suppose the bowl is spun at 500 RPM. Reference to any of several on-line calculators reveals that the centrifugal force acting on the spindle is about 57 pounds—more than the weight of the bowl. Similarly, doubling the speed to 1000 RPM would result in a centrifugal force of about 227 pounds.

As a second example consider a bowl blank 40 inches in diameter and 20 inches deep (a challenge for Emiliano’s new Stubby 1000). Under the same assumption as above, it would weigh about 600 pounds. Assume the same 2.5% unbalance centered at a point on the outer rim as before. At a speed of 200 RPM the calculated centrifugal force is 340 pounds. Doubling the speed to 400 RPM increases it to 1360 pounds.

The moral here is “balance the bowl blank as well as possible before turning on power and keep the speed way down”.
Just to concur with you Dennis, the example of loads you give are fine as long as the wood remains intact and nothing flies off at those speeds/weights. It is when the "unexpected" happens without warning that a serious situation could occur.
My early warning system is leaving my 2426 Oneway "floating" on 3/4" chipboard over 1" styrofoam that sit on concrete floor. (the whole shop is covered in this for foot comfort) I realize this is radical to opinions here, but it works for me and automatically keeps me turning safely. Under these conditions the lathe (legs) physically move approx. 1 1/2" every 7 years.
 
Joined
Oct 13, 2016
Messages
1,053
Likes
1,463
Location
Rainy River District Ontario Canada
Not to belabor the issue, but I think it is instructive to consider the size of the forces involved here. As a first example, consider a moderately large semi-circular green wood bowl blank that is 16 inches in diameter and 8 inches deep. Assuming that it a typical green wood that just floats or almost floats in water, it would weigh about 40 pounds. Further, assume that there is some aberration in the density or exact shape of the piece that it is unbalanced in a way that is equivalent to adding a 1.0 pound weight (2.5 % of the weight of the bowl) centered a point on the outer rim of the bowl. Now suppose the bowl is spun at 500 RPM. Reference to any of several on-line calculators reveals that the centrifugal force acting on the spindle is about 57 pounds—more than the weight of the bowl. Similarly, doubling the speed to 1000 RPM would result in a centrifugal force of about 227 pounds.

As a second example consider a bowl blank 40 inches in diameter and 20 inches deep (a challenge for Emiliano’s new Stubby 1000). Under the same assumption as above, it would weigh about 600 pounds. Assume the same 2.5% unbalance centered at a point on the outer rim as before. At a speed of 200 RPM the calculated centrifugal force is 340 pounds. Doubling the speed to 400 RPM increases it to 1360 pounds.

The moral here is “balance the bowl blank as well as possible before turning on power and keep the speed way down”.

You have it exactly right Dennis, and it seems to me a lot of turners do not appreciate the forces involved, if one turnes just small like 4 or 5 inch pieces the inertia is not very great, still can hurt you but unlikely to kill, take a 12 inch blank and crank the speed up to 2000 RPM as some have been known to do, a larger size chunk coming off and hitting the turner has a good chance to put him between 6 planks.

Advice like turning up the speed till the lathe start vibrating and than back off a hair is not good advice, asking for trouble IMO
 
Joined
Aug 6, 2009
Messages
693
Likes
497
Location
Lummi Island, WA
Following this thread and enjoying having the engineering expertise brought to bear. I’m now wondering if I should bolt my AB to the floor. I’m not on a slab - it’s a wood floor with doubled 2x12 joists on 12” centers (running perpendicular to the bed). I added two 6x8 timbers jacked up from the bedrock in the 5’ high crawlspace under the legs on both sides running parallel to the bed. Large unbalanced blanks will cause some vibration, but its never attempted to walk away. I keep the speed down until balanced.
Will there be a significant advantage to bolting down?
 

Dennis J Gooding

Beta Tester
Beta Tester
Joined
Apr 10, 2010
Messages
824
Likes
732
Location
Grants Pass, Oregon
Following this thread and enjoying having the engineering expertise brought to bear. I’m now wondering if I should bolt my AB to the floor. I’m not on a slab - it’s a wood floor with doubled 2x12 joists on 12” centers (running perpendicular to the bed). I added two 6x8 timbers jacked up from the bedrock in the 5’ high crawlspace under the legs on both sides running parallel to the bed. Large unbalanced blanks will cause some vibration, but its never attempted to walk away. I keep the speed down until balanced.
Will there be a significant advantage to bolting down?

If you have it leveled and it doesn't move around, then probably not. If it does move, then bolting it down will keep it leveled.
 

odie

TOTW Team
Joined
Dec 22, 2006
Messages
7,074
Likes
9,473
Location
Panning for Montana gold, with Betsy, the mule!
There is no question that a smooth vibration free circumstance promotes precision turning......to be sure, it doesn't guarantee it.....but it does create it's availability for further exploitation. From that point, it's up to the skill of the turner to take advantage of it. :D

It seems to me there are three elements to consider. The overall weight and balance of the individual piece of wood being turned......the rpm.....and the ability of the lathe to withstand the residual forces applied at any given rpm. All of these things, in combination, are what is considered "harmonic" vibration. THAT is what you have to control, in order to create the circumstances that will allow your skill level to succeed to the highest degree possible. The latter cannot exist without the former.

Advice like turning up the speed till the lathe start vibrating and than back off a hair is not good advice, asking for trouble IMO

I'm one who advocated what Leo is describing here.....until the invention of the "vibrometer" came into play. What he is saying is correct, within some limitations. The vibrations I'm detecting now, are with far greater sensitivity than what was detectable with my own sense of feel through my fingers. The result is, I'm now running my rpm's at approximately 75% (+/-) of what I used to. Since rpm can influence the quality of the cut, lowering it will require a greater attention to tool selection AND preparation, along with an evermore refined skill in making that cut. This doesn't mean that simply lowering the rpm is the answer......because "harmonic" vibration is not a constant throughout the rpm range. It also doesn't mean that finding the least harmonic vibration is the answer, either.......it's just a necessary component leading up to the most advantageous application of your own tool selection and acquired skills. :eek:

Getting back to Emiliano's original query.....bolting down the lathe does effect the ability of the lathe to be stable, in accordance with the forces applied.....and, in turn.....effects the circumstances that will create the opportunity to apply your acquired skills to their best advantage. As I said before, I believe adding weight to the lathe may have very similar effect as bolting the lathe to the floor.

Keep on keepin' on, gentlemen.......:)
-----odie-----
 
Last edited:
Back
Top