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Outboard turning - is this a bad idea

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Forum topic by Rink posted 02-08-2019 05:07 PM 858 views 0 times favorited 15 replies Add to Favorites Watch
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Rink

116 posts in 423 days


02-08-2019 05:07 PM

I have an old Delta Milwaukee 1460 lathe with 12” capacity, 1hp motor and a low speed of 435. I also have an auxiliary freestanding tool rest. The lathe is on a stand with wheels that allow me to move it, and cam levers on one side of the base that takes the weight off the wheels onto rubber feet. I’ve been happily turning bowls under 12” without any issues, but have been itching to try something larger.

I put a 14.5” blank on the outboard end, started it at low speed, and the lathe wobbled terribly. So, then I screwed some weights onto the blank on one side to try to equalize the weight. That actually helped, but not enough.

Then I piled bricks on the base, and that also helped but there was still too much wobble to work. Then I put an old dovetail jig which is very heavy on top, and that helped enough so that I could start scraping, but still too much wobble for accuracy.

So then I tried a flywheel concept and put a 5” weight on the inboard spindle. I thought this would tend to equalize any weight discrepancies.

This helped enough so that I was able to cut this bowl shape. There is now very little wobble.

Questions:

Am I harming the lathe and/or bearings with this flywheel?

After using the flywheel for a while, my fear of it being dangerous has lessened, but I’m still not sure.

There is still a little constant wobble, and if I press too hard with a chisel, the wobble increases. Then I have to wait a few seconds for it to stop. I can’t get a perfect cut. Is there a better way? Is the only way to do better for me to take the lathe off the stand and bolt it into the cement floor? I’d rather not do that – my workshop is small and it helps to be able to move things around.

Thanks for any advice, David


15 replies so far

View Brawler's profile

Brawler

34 posts in 216 days


#1 posted 02-08-2019 05:22 PM

I had a similar issue, I have an old Oliver 167. I anchored it to the floor. I just put it in the corner between the garage door and the wall. I also have all my machine on wheels, except for the lathe. I don’t ever plan on moving the lathe because I can’t think of a better pl

-- Daniel

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LesB

2089 posts in 3829 days


#2 posted 02-08-2019 06:35 PM

I would say you can’t put a 1 ton load in a 1/2 ton pickup truck. The springs, bearings and tires just won’t handle it.

You can turn larger diameters on the outboard side but not if they are heavy and out of balance. No matter how many bricks you put on. For instance I have turned a large bezel for a clock, about 1 1/2” thick by 3”across and 18” in diameter mounted to a piece 1/2” plywood with on problem, but there was not the bulky extended weight you are trying to work with. Also your use of the chuck only extends the weight further from the head stock. Try using a mounting plate to keep it closer in.

-- Les B, Oregon

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LesB

2089 posts in 3829 days


#3 posted 02-08-2019 06:36 PM

Something strange is happening on this thread. This is the second time I have posted a reply in the past week only to have it disappear and then end up double posted. I caught this in time to delete the second post.

-- Les B, Oregon

View gwilki's profile

gwilki

299 posts in 1859 days


#4 posted 02-08-2019 07:27 PM

The weight on the inboard side is not going to bring things into balance as it’s evenly distributed around the spindle. Since the blank is out of balance, if you are going to bring it into balance temporarily while you turn it finally into balance, the inboard weight must be out of balance opposite to the outboard piece. So, for example, if the heaviest part of your bowl is at 6 o’clock, you need to offset that with an equal weight at 12 o’clock.
I do off balance pieces, but I mount them so that I have a piece of plywood larger than the diameter of the piece between the chuck/faceplate and the piece. Then I hot melt glue blocks onto the plywood to counter the off balance of the piece.
Clearly, you need to keep changing the weight of the counter balancing as you true up and balance your bowl.
Assuming you have the bowl centered on your spindle, it will gradually come into balance. The exception to this is if the bowl blank is, for some reason, heavier on one side. If this is the case, you need to retain the counter balancing until the bowl is finished.

-- Grant Wilkinson, Ottawa ON

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OSU55

2298 posts in 2375 days


#5 posted 02-09-2019 01:38 AM

No, the flywheelis not harming anything. Mounting to a faceplate vs a chuck will help but difficult to know how much. Need dimensions/weights to calculate. Is the stand wobbling side to side – if so closing in the ends with plywood screwd into the legs will create a torsion box, much stronger/less movement. Unfortunately it appears it is difficult to add weight to the spindle end with the motor and pulleys, but weighting the spindle end will help much more – your whole stand may be twisting in line with the lathe bed. Mass is your friend here. Iron/steel/lead any where on the spindle end,

I had the HF large lathe for 6 years – pretty similar in stand design and maybe lighter, with a low speed of 650 rpm. I turned a lot of pieces this size. One advantage was the swivel head – I rotated 90 to be inline with the long axis of the lathe, which provides more resistance to the forces generated.

View Lazyman's profile

Lazyman

3385 posts in 1773 days


#6 posted 02-09-2019 03:52 AM

My first thought is that perhaps the real problem is that the stand itself is not that rigid? You added a bunch of weight down low but if there is any flex at all where the legs meet the top, an off balance blank is going to move the top around even if the bottom stays relatively still. I wonder if some cross braces on the ends would help? You could even attach a plywood plate to each end to make sure it is rock solid?

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View mike02719's profile

mike02719

107 posts in 4172 days


#7 posted 02-09-2019 02:20 PM

Necessity is the mother of invention. Looks like you went to the max trying to do something. I am always amassed at how ingenious people can be when they want to do something. Your lathe should be able to withstand the punishment given to it. How stable is your tool rest in relation to the lathe mainframe? You can’t have the lathe vibrating and the tool rest not vibrating in sync. You may try c-clamping the toolrest to the lathe. Also I think 435 is a tad fast for a large outboard turning.

-- Mike, Massachusetts

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CMDEvans

34 posts in 2911 days


#8 posted 02-09-2019 02:52 PM

I have that lathe. You aren’t harming anything by adding the inboard weight. I would check your bearings if you ran it for any length of time out of balance. On mine I’ve had to tighten the “thrust nut” bearing keepers up several times after turning out of balance pieces. Eventually I’ll put real thrust bearing in there, but it hasn’t been much of a hassle.

-- We hold these truths to be self-evident, that all men are created equal. . .

View Planeman40's profile

Planeman40

1406 posts in 3147 days


#9 posted 02-10-2019 04:43 PM

I have that exact same lathe and have turned large items on the outside of the headstock. Don’t worry, it can take it. And I had the very same balance problems you did. Once I took enough wood off the blank to even it out, all ran smoothly.

-- Always remember: It is a mathematical certainty that half the people in this country are below average in intelligence!

View Nubsnstubs's profile

Nubsnstubs

1556 posts in 2116 days


#10 posted 02-10-2019 05:10 PM

I started turning on that lathe also. When I got, it didn’t have a motor, so I got a VFD, 2 hp 3 phase motor, and then started using it. The slow start and slow speed made it as comparable to the Powermatic 3520 I now have, with the exception of the swing. It’s a good lathe, but has limitations that can be overcome by upgrading the drive, possibley increasing the swing. I wouldn’t go over 16”.

Looking art the first picture with all the bricks and the motor and the jack shaft, I can’t believe that you can’t get your speed any lower than 435. What is the motor speed??

Planeman, CMDEvans, and Rink, can you tell me what your serial numbers are. I found 1 lathe in Oklahoma that was under 97 numbers off from mine. It originally was sent to Arizona to the school system in 1947. The Oklahoma owner bought it in Tonapah, Arizona, and took it back home to Ok. ............... Jerry

-- Jerry (in Tucson) www.woodturnerstools.com

View Rink's profile

Rink

116 posts in 423 days


#11 posted 02-11-2019 06:21 PM

Thanks everyone for your feedback! This weekend, I made some changes.

I took the wheeled base off. I had lumber on hand to laminate some plywood to make wider stance legs. On the bottom of the base I glued on pieces of a mat made from recycled tires to help with vibration. Then I attached a shelf to the new base for rigidity and stacked over 300 pounds of bricks onto that shelf. I leveled the lathe, tightened up bolts, screws and pulleys. It feels like a rock now.

Then I put the chuck and bowl on the outboard spindle, and it still shook!!

I have two more things to try. One is that, as OSU55 and Nathan suggested, I’m going to screw plywood to the shelves on both ends and on the back. That should add some rigidity. Second is that, as Les suggested, I found a left hand thread faceplate on Ebay that’s on it’s way. That will bring the bowl closer in and should help. If not, I may give up on outboard turning.

Also, I forgot to take into account that by adding the base to the lathe, my independent tool support is now too short. I can sort that out, I think, but, as Mike suggests, I’d love to figure out a way to attach a support to the lathe for use with outboard turning. Any ideas for that?

CMDEvans, I don’t know what thrust nut bearings are, let alone how to check, tighten or replace them. Can you point me to some information on that?

Jerry, the serial number of my lathe is 39-6497. Does that mean it was made in 1939? My motor speed is 1725. Any suggestions on how to slow the spindle down more? I think I’m maxed out on pulley configurations.

David

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MrUnix

7383 posts in 2585 days


#12 posted 02-11-2019 06:29 PM

Jerry, the serial number of my lathe is 39-6497. Does that mean it was made in 1939?

Nope – means it was made in 1945.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Rink's profile

Rink

116 posts in 423 days


#13 posted 02-13-2019 05:23 PM

Success. At least, I think so.

I added a side support, screwing it in on four levels. And I added a back support, screwing it in on the backs of the shelves.

I also had to raise the outboard support, so added a base. It’s pretty stable.

I don’t have experience on many lathes so I don’t know how much vibration is acceptable. I didn’t have a nickel handy, but I found this metal pin that I stood upright on the lathe bed. With the outboard bowl rotating, it stood easily. There’s not absolutely no vibration, but it’s very minimal.

So, I’m good to go. Hopefully this thread will help someone else in the future.

Remaining questions:

Jerry – I just realized that you made a suggestion that I had missed: possibly increasing the swing to 16”. Did you do that on your 1460 with 2” risers? Also, did you get a slower speed than 435 with your 1460?

Anyone – Do I need to worry about my thrust nut bearings (or any bearings)?

Thanks again for all advice.

David

View Nubsnstubs's profile

Nubsnstubs

1556 posts in 2116 days


#14 posted 02-14-2019 04:31 AM

David, I got the 3520 before I got a chance to increase the swing. It’s really pretty simple, but you need to be accurate in doing this. A 2×2 white oak, or some other eastern hardwood to support the headstock would work, but metal would be more secure. Fit it to the bolt holes, get longer bolts, raise the headstock up on the risers, and bolt it down. The tailstock will be about the same, except you need to have the guide absolutely centered to keep the tailstock aligned with the spindle. My description below would be the same whether you do a half inch, or two inches.

As soon as I got the lathe that was just a headstock, ways, banjo, and who knows where the tailstock came from. All I wanted to do was turn so I immediately removed the headstock pulley and made one 2” and 4” to fit a J8 belt. I installed a 3500 rpm 2 hp treadmill motor with a 2” drive pulley.The lowest speed was near 40 rpm, and the highest was equal to motor rpm.

The tailstock was for an 11” swing. I have access to a machine shop. I got a piece of 3/4” thick steel plate the size of the base. It was machined to be 1/2” thick where it fit on the ways, and was left at 3/4” at the center the width of the ways gap forming the guide. I then drilled and tapped holes at the corners of the funky tailstock. Next , I drilled the holes for the base and mounted it to the tailstock. The clamp hole was drilled at the same time. I used an eye bolt for the clamp.

When it was put together, it was aligned on swing, but the side to side was off a RCH, so I drilled and tapped the step on the base that went into the ways, and inserted set screws.. I was able to align it to where it was on the money.

Since all that work I did, I had to replace the motor with a 3 phase 2 hp, and got a VFD. It was still 12” swing. I turned a lot of pieces upwards of 11 1/2” od. I just don’t remember any really off balance stuff. But, my rpm’s were started very low, and increased as it was shaped and stayed in balance

About a month ago I gave this lathe to a friend in Missouri. I hope he uses it. I also told him I’m heading east again in 18 months, and if he hasn’t started making things with it by then, it’s coming back to Tucson

My lathe was made in 47, but I think the serial ended with a 7. I can’t find the paper I wrote it on to get the other numbers. It’s here somewhere.. .............. Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

View Rink's profile

Rink

116 posts in 423 days


#15 posted 02-15-2019 06:26 PM



David, I got the 3520 before I got a chance to increase the swing. It s really pretty simple, but you need to be accurate in doing this. A 2×2 white oak, or some other eastern hardwood to support the headstock would work, but metal would be more secure. Fit it to the bolt holes, get longer bolts, raise the headstock up on the risers, and bolt it down. The tailstock will be about the same, except you need to have the guide absolutely centered to keep the tailstock aligned with the spindle. My description below would be the same whether you do a half inch, or two inches.

Thanks, Jerry. I’ve been thinking about this and doing some research. I think I’m going to play with the lathe the way it is now for a while and see how it goes before starting a project like this. Adding riser blocks doesn’t seem like that difficult a project, but I would be using wood which isn’t as accurate as metal. Also, once I add riser blocks, I’d have to figure out a way to raise and extend the banjo and tool rest. I think there are extensions sold for this purpose, but then I’m throwing more money at this. Time is my pleasure, but money is money.

David

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