Monster Lathe Phase One (and a "small dilemma") [Archive]

David DeCristoforo

07-22-2012, 2:59 PM

Spent a few hours patching up all of the small voids in the concrete and easing the hard edges. Then a coat of "hammer finish" paint. Also woking on rearranging things to fit this into my workspace.

Now… the big dilemma. Some of the pics Mark posted show a jackshaft with a large reduction pulley and some step pulleys. Pricing all of the stuff needed to replicate this and with the big wheel, the step pulleys, bearings and all of the misc hardware needed to get it all working and I'm in for almost as much as it would cost for a 3ph motor and a VFD.

I know VFD setups have been discussed frequently on this forum and I have read most of the threads. I seem to recall someone mentioning a VFD/motor combo that was not too expensive. Some advice here would be most welcome. My knowledge of these setups is most basic. I would like to have a 1.5 - 2hp motor and I know the VFD and the motor have to be matched up in some way. I can input either 110 or 220.

Meanwhile, I am working on the other "major missing piece"... a tool rest setup!

Oh and one other thing. I have no idea what the exact size/thread count in the spindle end is. I tried to measure it and it could be 1 1/8, 1 /3/16 or 1 1/4" depending on which way I squint and seems like I could count either seven or eight threads per inch again depending on how I squint... I emailed Mark to see if he knows exactly what adaptor I need but I think he might be on vacation!

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Roger Chandler

07-22-2012, 3:17 PM

Nice job on the paint, David. I really like your idea of going with a VFD and matched up motor, especially since it would be in the ball park on price. If it is possible for you to find a 3hp, it would be a great addition and make your lathe truly in a league with the big boys as to power.........perhaps a find will come along........perhaps someone in this community will have a lead for you.

Wonder if you sent a picture with the dimensions to someone like Brent English, if he would fabricate a tailstock for you? Some pics of the underneath where the clamp plate would be and precise dimensions, would likely be enough info in order for him to fabricate something...........then, I also would check with Jeff Nicols........he might take on the challenge since he had some interest in this unit early on..........one does not know unless they communicate.

Good luck on this......we are all watching with great interest in your progress.........:)

Nate Davey

07-22-2012, 3:58 PM

Man that looks good, David. Have you seen these (http://www.dynamotors.com/) motors? Don't know the cost but something to think about.

David DeCristoforo

07-22-2012, 4:27 PM

Nice looking motor. But no indication of price. Low RPM is 800 so step pullys would still be needed. I would love to know the cost. Maybe a phone call on Monday...

phil harold

07-22-2012, 4:38 PM

I am fan of that hammer paint!

I like the idea of variable speed motor

and with most boy toys,

the bigger the better!

Nate Davey

07-22-2012, 4:46 PM

This pulley calculator (http://www.temecularodrun.com/ref/rpm_calc.asp) may be helpful as well.

Phil Harris

07-22-2012, 4:48 PM

Hi David

I'm going to the Nor-Cal Woodturners club meeting in Sacramento Tuesday evening. If you would like me to I could leave early and bring by my chuck that has a 1 and 1/4 by 8 tpi insert and we might possibly resolve what size the spindle end is. I will send you an email with my phone number and you can contact me or send me your address by email.

Phil Harris

David DeCristoforo

07-22-2012, 5:09 PM

That would be great. I'm pretty sure it's 1 1/4" X 8TPI but it would be nice to know for sure. Mark said it was "the standard" size but there seems to be a lot of "standard sizes"!

Alan Trout

07-22-2012, 7:17 PM

David,

You can get a 3hp VFD and motor in the $600 to $700 dollar range. Talk with Brent over at Robust. He can give you a good idea of actual cost. I have always found him very open about such information and always willing to help.

Alan

David DeCristoforo

07-22-2012, 7:55 PM

Thanx, Allan. But six or seven hundred is out of my price range right now. I'm trying to do this "on the cheap" if at all possible. There's used 3ph motors to be had for under a hundred and the VFD looks possible at under two.

Roger Chandler

07-22-2012, 8:36 PM

I bookmarked this site about a year or so ago..........

http://www.dealerselectric.com/

Don't know if you could use this info or not, David.........but they have motors and inverters.........maybe useful for your lathe build, and some of the prices seem pretty good to me.

philip labre

07-22-2012, 10:03 PM

Looks good, David! I think you are on the right track with a 3ph motor and an FM50 VFD for variable speed and reverse. Lots of good info on VFD's in the electrical forum at OWWM too.

David DeCristoforo

07-22-2012, 10:40 PM

"I think you are on the right track with a 3ph motor and an FM50 VFD..."

I'm leaning hard in that direction. I would love some specific information like how slow this unit will run the motor etc. I'm looking for a spindle speed range of 200 - 2000 RPM. I will probably try calling a dealer tomorrow...

Richard Bell CA

07-22-2012, 10:56 PM

David:

If Phil Harris stops by to check the spindle threads, you might consider hitching a ride with him to the Tuesday night Nor-Cal meeting if you have the time. We installed a Teco FM50 VFD on one of the club lathes and it is located at the meeting site, so you can see it firsthand. I also installed a slightly different TECO model on a disc sander in my shop. Both VFD's came from Dealers Electric and have been working well. You will probably need to use 220v for the size of motor you are talking about. You are also welcome to visit my shop to examine the setup on my disc sander - I live about an hour east of you.

Richard

philip labre

07-22-2012, 10:59 PM

I will probably try calling a dealer tomorrow...
I wish I could help, but I started researching this, then a 10hp motor came my way for free and I built a rotary phase converter for my shop instead.

Jim Underwood

07-22-2012, 11:14 PM

Well if you can't measure the spindle dia and thread pitch by eye with a ruler, you could always get a thread pitch gage. They are pretty cheap. As for the spindle size, if you have a HF nearby, then those 6 in digital calipers are relatively inexpensive as well - $10 if you catch them on sale. I'd give you a coupon if you were close by...

Rick Markham

07-23-2012, 2:31 AM

I'm contemplating a project, which has a similar problem (needs pulleys) Is there any reason a guy couldn't just turn your own pulley's out of aluminum blanks? or lignum vitae?

The lathe looks great David, like an entirely different beast! You put some time into it, it's going to be a sweet machine.

Those big brushless motors look really nice, I bet the price is high though. (Though brushless motors "supposedly" will outlast brushed motors)

Dale Miner

07-23-2012, 8:25 AM

David,

Investigate the drive system well before finalizing the design. Going on the cheaps or going a wrong direction might make using the lathe a chore or worse.

Take a look at some of the larger swing lathes that are offered by the better manufacturers. They all use multi pulley designs with the VFD. They all also use poly V belts. The advantage of the poly V belts is they can wrap around small pulleys and still drive well. A standard V belt loses it's ability to carry torque as the pulley size becomes smaller. In the picture of the headstock, it looks as though there is a single groove standard V belt pulley. If you plan on doing items that are at or near the swing capacity of the lathe, I doubt that you will be able to transmit sufffcient torque to the spindle from that single pulley to take more than (continous) light cuts. A double V belt with larger diameter pulleys might be needed, or a single wider poly V belt on larger diameter pulleys. In order to get a usable speed range, and maintain avaliable torque throughout the range, it very probably will be neccessary to use a step pulley arrangement somewhere in the drive system. With a VFD, the motor speed can be brought down to virutually zero, but the torque of the motor does not increase to any extent as the speed slows. To maintain horsepower from the motor the rpm's of the motor need to be kept up fairly high; A step pulley/jackshaft arrangement seems to me to be needed for that purpose. A VFD reduces the need for a wide variety of steps on the pulleys, but does not eliminate the need for at least some steps.

You mention a desired speed range of 200 to 2000 rpm. If only a single step pulley reduction is used, and the motor max rpm's are held at 4000, then the motor would be spinning 400 rpms with a spindle speed of 200. Assuming a 3 hp 1800 rpm motor, slowing the motor to 400 rpm reduces the available hp to 400/1800 x 3 = 2/3 hp. There might be some slight increase availble from the use of the VFD's characteristics, but not enough to garner the full 3 hp at 400 rpm. No doubt the 200 rpm's would be used on the largest swing items, where the need for torque is at it greatest. At times like that, it would be desirable to have the motor rpm's close to nameplate.

Just my thought, but is 2000 rpm going to be used often, if at all? Shooting for a 1200 rpm top speed might make keeping available torque throughout the entire speed range easier and less expensive.

BTW, what is the swing of the lathe?

Your paint job is looking good and is perfect for the machine.

Reed Gray

07-23-2012, 11:36 AM

Well, any motor above 1 hp runs better/more efficiently on 220 volt current. That much I remember from when I was researching setting up a shop. As for a motor to run your lathe, I have a Robust Liberty lathe with the 2 hp 'vector drive' motor. I don't know the specs on the motor, but it has more than enough torque, surprising for one so small, and it only uses one pulley. If you could get one from Brent, he could help you get it set up right. I do know they have been using the brushless motors in model cars and planes, and they have amazing amounts of torque. Stuart Batty had a really interesting motor on his Omni Grinder (still isn't out yet... AARGH!!!, been teasing me for over a year now) that is supposed to be 2 hp, and will be about the size of a 1/2 gallon milk carton. Sounds like a fun project.

robo hippy

David DeCristoforo

07-23-2012, 1:02 PM

Step pulleys are definitely going to be in the picture. Here's how I'm figuring it:

Motor Speed @ 600 RPM w/ a 2" pulley on the motor and a 6" pulley on the main shaft = 200 RPM

Motor Speed @ 1750 RPM w/ a 5" pulley on the motor and a 4" pulley on the main shaft = 2187 RPM

I was thinking about setting up a jackshaft arrangement the way Mark showed in some of his pics but then realized that there would be no way to use step pulleys there because the main shaft and the jackshaft are both fixed. I could possibly use "Power Twist" belts which could be "opened" to move from step to step but that's getting kinda cumbersome. And even so, it's going to be hard to get the speed range I want using only pulleys. The VFD seems like a much more "elegant" solution and, as I said, it's almost a "wash" cost wise. The pulleys, shafts, bearings, etc total out to almost as much as a VFD and a motor.

I'm also looking into the "Dynamotor" that Nate posted a link to. They seem to max out at 1.5 HP but that would be enough "for now". I do have 220 available so that is not an issue.

BTW, the "capacity" of this thing is going to end up at around 40" diameter with a 20" swing. At this point, I'm not planning to use the bed, at least not in it's current configuration so I'm working on an articulated tool rest design that will allow a large swing. Not that I plan on turning anything that large but it could be done. I'm thinking that if I ever do set it up with a bed, it will be more of a "stubby" style arrangement. Not thinking about doing any spindle work on this! But it would be nice to be able to bring a tailstock into play at some point.

Dale Miner

07-23-2012, 3:14 PM

David,

Some thoughts.

If you use a VFD, it is fairly common to 'overspeed' a 1750 motor to about 3600 rpm. On the 3520b the namplate rpm is 1750, and wide open my tachometer has it running above 3500 rpm (mechanical limit of the tach). If 2000 rpm top speed is your goal, you could still have a smaller pulley on the motor than the spindle.

Also, it makes life simpler when changing pulley ratios if the combined diameter of the pulleys on all ratios are the same. In the example you mentioned, the 2"/6" and 5"/4" would mean that there would need to be considerable adjustment avaliable to take up the extra length of belt when going to the slower speed.

In a jackshaft reduction arrangement, the step pulleys are typically put on the motor and the jackshaft. The jackshaft to final shaft is usally not disturbed when making speed range chages.

It might be a good idea to look into a VFD that has external dynamic brake resistor capability. Shutting down a near 40" diameter piece will result in quite a bit of energy that needs to be dissapated somewhere. A friends 24" Oneway that lacks the brake resistor will trip out when shutting down larger pieces. Another friend fried his VFD on a 3520 when shutting down a large piece.

Mike Cruz

07-23-2012, 4:09 PM

DD, looking good so far! As for the motor VFD thing. I'm not sure about a combo of the two. But I have found good 2 and 3 hp Baldor 3 ph motors for $75-100 at my local motor shop (I've bought three of them so far from them, and all have worked flawlessly). The VFD (TECO FM-50) for one of those should run $150-200 respectively (new). So, you should be able to get set up for $225-300 (and some shipping, maybe). Not sure if that is the number you came up with regarding jackshafts, pulleys, and bearings. Keep the posts and pics coming!

Baxter Smith

07-24-2012, 1:19 PM

Cool pics!! Thanks for sharing them!

Dick Strauss

07-24-2012, 2:05 PM

Some thoughts...

One pulley is plenty for 3hp...think back to when a car used a 10hp AC compressor driven by one std v-belt with no issues.

Mike C is right...used 2-3hp 3ph motors can be found on the cheap. Inverter duty motors are better but not necessary for our limited duty use of motors according to folks in the know.

HP vs Torque...you need torque, not hp to turn large items. Some motors will have constant torque down to 1/1000 or 1/20 of the nominal speed. You can mount cast iron 5-position stepped pulleys on the motor and drive spindle like the Maska ones (http://www.electricmotorsite.com/c/pul_step_a/A+Belt+Step+Pulleys.html) if you need more torque.

TENV (totally enclosed/non-ventilated) motors will do better at slow speeds (with VFD) because of their mass that doesn't rely on a fan for cooling. TEFC (totally enclosed/fan cooled) motors will tend to run hot at slow speeds because their fans don't move enough air.

Good luck with your project!

John Aspinall

07-24-2012, 2:30 PM

Oh and one other thing. I have no idea what the exact size/thread count in the spindle end is. I tried to measure it and it could be 1 1/8, 1 /3/16 or 1 1/4" depending on which way I squint and seems like I could count either seven or eight threads per inch again depending on how I squint...

I would think that a small investment in a thread pitch gauge (e.g. http://www.amazon.com/GRIP-Metric-Thread-Pitch-Gauge/dp/B004ROIU2A or http://www.parts-express.com/pe/showdetl.cfm?Partnumber=365-158 ) and a cheap digital caliper (e.g. http://www.harborfreight.com/6-inch-digital-caliper-47257.html or http://www.maxtool.com/us/products/CP5906.asp ) would immediately answer that question, and pay off in future use.

David DeCristoforo

07-24-2012, 8:30 PM

Phil Harris stopped by this afternoon with a 1 1/4" X 8TPI chuck adaptor and it screwed right on. So now I know the spindle size. Just right for a Nova Titan chuck! Also have a line on a motor setup that I think will be of inerest to more than myself. More on that soon...

Mike Cruz

07-24-2012, 9:51 PM

5 hp?!?! Cool!!!! Yeah, DD, I kinda assumed it would be 1 1/4" x 8 TPI. That is pretty standard for PM and other larger lathe manufacturers. When I had Jeff build my bowl lathe, I asked him to make the spindle 1 1/2" x 8 TPI because that is what my PM90 is, and that way all my chucks and faceplaces will swap over without any "changing out inserts" or spindle adapters.

neil mackay

07-24-2012, 11:13 PM

[contemplating a project, which has a similar problem (needs pulleys) Is there any reason a guy couldn't just turn your own pulley's out of aluminum blanks? or lignum vitae?

If get down to your local steel scrap dealer and look for an old beat up bench drill and get the stepped pulleys of it.

Olaf Vogel

07-25-2012, 7:26 AM

Some thoughts...

HP vs Torque...you need torque, not hp to turn large items. Some motors will have constant torque down to 1/1000 or 1/20 of the nominal speed. You can mount cast iron 5-position stepped pulleys on the motor and drive spindle like the Maska ones (http://www.electricmotorsite.com/c/pul_step_a/A+Belt+Step+Pulleys.html) if you need more torque.

I totally agree with this once you get into larger diameters (ex. 20").

I have almost exactly that setup: 3 hp, 3 ph with a VFD (that converts from single phase to 3 ph).
For roughing in large diameters, I had to slow it down a LOT to reduce / eliminate vibration. At that point, the motor didn't have the torque to allow decent cuts. The constant torque feature of VFD's only works to a point. Its still the motor that has to create the torque and if you're at 5-10% of its rated speed, it just can't do it.

The solution was to create a secondary mechanical speed deduction. I.e. larger pulleys. Being cheap and impatient, I hit Home Depot for some Birch plywood, laminated a chunk and turned a very large v-belt pulley myself. Not the prettiest, but works well and is replaceable. The smallest pulley is 6", the largest 14". I still use the VFD for fine speed adjustment and change the belts to different pulleys only when going to a very different sized piece.

In my case, the pulleys are between the bearings so its pain to mount new ones. But in case of the Monster, they seem to go on the end which should be really easy.
I used v-belts because they are cheap and easily available. But for really high torque, you may need several in parallel to avoid slipping. In that case, making the pulley's yourself is much cheaper, because the commercial pulleys for multiple belts get very pricey and hard to find.

Looks like a great machine. Once the initial issues are sorted out, i'm sure you'll love it!

Mike Cruz

07-25-2012, 8:09 AM

Olaf, for the reasons you just described, that is one of the things I love about my PM90. I have a 2 hp 3 ph motor with a VFD. I have manual control via the Reeves drive for speeds from 400 to 2200. If I need to drop below 400, then I use the potentiometer for the VFD. That way, if I wanted to drop as low as 200 rpm, I'd still be at 50%...which is still high on the torque output. But I agree with you that if you are down to 5-10% using your potentiometer, you'll lose a significant about of torque.

David DeCristoforo

07-25-2012, 1:28 PM

The manufacturer of the new "Dynamotor" is sending me a 1.5 HP 220v motor for "testing and review".
237645
There are some advantages and some disadvantages to going this way. On the plus side, it's pretty much a "bolt on" solution. Everything is self contained in the motor itself although I will be rigging an on/off switch on the front side of the lathe (Mark provided a box cast into the front for exactly this purpose). Obviously I would like a more powerful motor but realistically, I'm not going to be spinning 48" diameter chunks of wood on this thing. At least not right away! And the whole thing can be upgraded at some point if I find I need more power. Also, this motor is designed to maintain a high torque level at lower speeds. Even so, the mfgr recommends keeping the motor at 600 RPM or better to maintain maximum torque. The speed range of the motor is 400 - 2400 RPM so some pulleys are going to be needed. The spindle already has a 6" pulley so I plan to mount two pulleys on the motor, a 2" and a 6". This will give me two speed ranges. With the motor dialed down to 600 RPM, I can get the low end spindle speed down to 200 RPM with 2400 RPM being the high end. This motor is full of "new age technology" and that's a lot of little gizoids and rizmos, something that I have always tried to avoid when making tool decisions. But it's a beauty and will look great hanging off the back of the lathe and, hopefully it will work well forever. A full review on this motor is in the offing.

As to the tool rest, here is my basic plan:
http://www.daviddecristoforo.com/Misc/tool_rest.pdf

Still thinking about this one but I sent a copy of this to Jeff Nichol and also to a welder friend who used to live here but moved "up north" and may or may not be able to do this. This is the biggest "sticky wicket" at this point because I have zero tools for making anything like this.

So that's it for now.......

Rick Markham

07-25-2012, 3:33 PM

David, I will be interested to see what you think about the brushless motor. They tend to have some different characteristics than brushed motors. These are the first large AC motors I've seen, I know their smaller DC counterparts outperform traditional DC motors. Definitely let us know your thoughts, it should offer higher torque in a smaller package, with the benefit of outlasting traditional brushed motors. (They also tend to sound different)

Mike Cruz

07-25-2012, 3:51 PM

DD, I picked up a VEGA bowl lathe with a 24" swing a little while back (ended up selling it when Jeff made me the other bowl lathe). It came with a 1/2 hp Baldor motor! Yes, 1/2 hp. The reason, is that it had a jackshaft, thereby increasing the torque. So, if you want to make "sure" that that 1 1/2 hp motor will be enough, use a jackshaft.

As for the tool rest, is that supposed to be bolted down? Might be a bit tippy if not...

David DeCristoforo

07-25-2012, 4:39 PM

"They also tend to sound different"

That's one of the things the guy mentioned. He said, it's not loud but it sounds different from a "regular" motor. Remaining to be seen (or heard!)

"...tool rest...Might be a bit tippy..."

I'm thinking that the steel plate gussets should make it pretty rigid. I have not come up with "specs" on this yet but I'm thinking that the main column would be 2" steel pipe which should also be pretty rigid. I'm not wedded to this design and am open to any and all suggestions at this point. I was looking at some pre-made units like the one Robust sells but OMG! The prices! Like I thought hey... I could rig up a PM 20" bed extension and get a PM tailstock and have a "stubby bed" thing! That would be cool. But the bed extension alone is twelve hundred bucks! Not in the cards right now. I might still need to work out some kind of short bed/tailstock setup because it would be great to be able to bring a tailstock into play. And I'm already thinking about trying to find someone who could bore a 1/2" hole through the spindle to allow for vacuum chucking.

A jackshaft might still factor in but I would like to just lap the motor on and see how it works. Then, if it's needed, a jackshaft could easily be added. But if I can keep it simple for now, that would be good...

Thom Sturgill

07-25-2012, 6:02 PM

One suggestion on the tool rest would be to make the foot adjustable vertically (with a locking mechanism of course). Floors are never completely level and true, and I'm sure that's true of your tent as well.

I would suggest either welding a nut on the end of the main 'L' tube and all-thread on the foot plate with a lock nut on the all-thread, or just duplicate what you are probably doing at the top for the tool rest post and drill a hole on the side of the L tube and weld a nut on so that a threaded handle can lock the foot post.

Making that adjustable also gives some lee-way on mounting that to the monster once its fabricated.

Mike Cruz

07-25-2012, 10:00 PM

DD, two thoughts. If you really want a bed, see if you can pick up a used old parts lathe. I've seen 'em around. There's even a PM90 one on Ebay for $160 right now in CA. Item number: 350582420514

Secondly, here's a link to a guy's bowl lathe and how he tackled things. http://www.winburn.com/AboutMe.asp Maybe that'll give you some ideas...

David DeCristoforo

07-25-2012, 10:28 PM

I've been looking at that lathe for quite some time now. That's very close to how I would like to do a bed. Only I might go a bit longer to accommodate a tailstock... Sure wish my welder buddy hadn't moved!!!

Rick Markham

07-26-2012, 3:17 PM

DD, The brushless motors I have heard sound "off" for a normal electric motor, it's just enough different in motor noises that it would make you think something isn't right. (it's just different from what we think an electric motor sounds.)

If you had a friend at a machine shop, you could have him make you some beefy articulated arms, using large thrust bearings (like on the Kobra) for your articulated tool rest. If you used a stack of two like in your drawing you probably wouldn't even need a foot on the bottom (other than to keep it where it needs to be) I guarantee there wouldn't be any vibration/deflection. You could set two pickup trucks on it :eek::D (you know you want to)

David DeCristoforo

07-26-2012, 4:57 PM

"If you had a friend at a machine shop..."

I only wish. I used to have such a friend. He was an amateur machinist and had a "full on" machine and welding shop in his garage. Plus he was the kind of guy who would leap right off the wall at the mere mention of such a project. Unfortunately, he moved to Arizona some years back and , more unfortunately, his parting of the ways with his wife at the time was somewhat less than amicable and she made mention of the bottom of the Sacramento river when the subject of his tools came up….

I also had another friend who was a metal sculptor and ran the UCD welding shop. It was a "dream job" but he met a lady who lived in Washington and… well… you know how that goes.

So at the present time, I am bereft of such resources and lacking is any of the equipment needed to make this stuff. If I had some welding kit and metal cutting and drilling tools, I would be out on the back patio on my hands and knees right now...

"...You could set two pickup trucks on it...(you know you want to)..."

One pickup truck would do fine....

David DeCristoforo

07-26-2012, 8:04 PM

Roger Chandler

07-26-2012, 9:39 PM

On paper that looks like it will work, DD...........the actual hookup of every component will tell the story.......looks like you are on your way........good luck!

Rick Markham

07-26-2012, 11:33 PM

If I had a knee mill, and the metal lathe that's on my eventual "to-do" list (right after the freestanding shop in my backyard, on said list) I would jump on the opportunity to make the parts.

Maybe it's time to make a new friend in the Metalworking section of the Creek. (If it's still on here and active)

David DeCristoforo

07-26-2012, 11:37 PM

"If I had a knee mill, and the metal lathe..."

If I hade those things, I'd invite you over to help me make the parts!

Rick Markham

07-26-2012, 11:46 PM

"If I had a knee mill, and the metal lathe..."

If I hade those things, I'd invite you over to help me make the parts!

If you had those and you invited me over you would probably have to chase me off LOL

Van Huskey

07-27-2012, 2:52 AM

David, do you have a price on the Dynamotor? It can't be "cheap" but I have several projects planned using VFDs and I would love to try one if it is even in the ballpark for me cost wise.

Rick Markham

07-27-2012, 4:15 AM

David, do you have a price on the Dynamotor? It can't be "cheap" but I have several projects planned using VFDs and I would love to try one if it is even in the ballpark for me cost wise.

Lurking again :p When are you finally going to come to the dark side?

Van Huskey

07-27-2012, 9:18 AM

Lurking again :p When are you finally going to come to the dark side?

Always lurking... As to your question when I get an American Beauty for $29.95 shipped... actually I have already started picking up small items to lessen the blow, like a couple of chucks and extra jaws, Wolverine etc.

Dick Strauss

07-27-2012, 10:13 AM

For your two pulleys 2"+6", you'll probably need at least 3" of shaft length on the motor (the 2.3" and 4.95" pulleys are about 1.375" thick each). These single pulleys are available through Grizzly, Electric Motor Site, etc. (After further research I found that unfortunately the specs call for a 2.06" x 5/8" diameter shaft length for the 1.5hp motor)

For whatever reason, the 1.5hp versions of this motor are non-continuous duty cycle (according to their data sheet) similar to compressor motors. I don't know what the derated duty cycle is but this may be a show stopper for you.

David DeCristoforo

07-27-2012, 2:33 PM

No worries. I'm sure I can figure out how to gang two pulleys together!

I have a call in to the guy to ask about the duty cycle but when I spoke to him before and described the intended use of the motor, he had no issues with it. I'm sure the motor will work fine!

David DeCristoforo

07-27-2012, 2:36 PM

The tool rest for the "monster" is going to be fabricated by SMC's "favorite tool maker", none other than "our own" Mr Jeff Nichol! I'm thrilled to have Jeff be the one to make this for me. I have one of his steadies and the workmanship is top notch so I know the tool rest will be likewise. Plus, Jeff has some ideas on improvements to my basic design. I'm sending him the necessary information today. We're sneaking up on it here….

Roger Chandler

07-27-2012, 2:40 PM

Awwriiightttt! Jeff is a good one for this.........way to go Jeff for putting your stamp on this project........the lathe might belong to David, but with all his posts and the original fabricator of this, putting all the process on SMC, it almost feels like an SMC family project! Progress..........tis good 'eh?

Rick Markham

07-27-2012, 2:48 PM

I'd say without a doubt in my mind, that Jeff is the man for the job! He amazes me with his metalworking (and woodturning) abilities. I can't wait to see his take on this!

Nate Davey

07-27-2012, 4:46 PM

Awesome progress, David. Really looking forward to your thoughts on the motor.

george wilson

07-28-2012, 12:36 PM

You'd better be sure that a VFD operating a motor at very low RPM'S will have enough oomph to not stall out when turning large diameter work. Even my 20" swing General wood lathe with VFD had a 4 speed step pullet in the headstock to assist in slower speeds with the VFD.

David DeCristoforo

07-28-2012, 12:52 PM

Jon Prouty

07-28-2012, 1:37 PM

Jeff notified me this morning that he will not be able to make the tool rest. He is buried under a heap of other projects. So I'm back to square one on that score. By the end of next week I will have this under power and ready to go. I'm still "on the fence" about the ballast section and how I will integrate it but it will for sure be mounted off the "back" side. But that is a small "issue" and the tool rest is the "big one" at this point.

Hey David,
how about fabricating the tool rest from wood and adding drill rod to the working area? This is the way I would go if I were in your situation. Another option, post on CL that you are needing some fabrication done and I'm sure you will get some offers.

Jon

Mike Cruz

07-28-2012, 5:46 PM

I was wondering how Jeff was going to resist the urge to build this! I know he's busy, tired (exhausted), and overloaded. But the creative side of his brain probably couldn't walk away...

Mike Cruz

07-28-2012, 5:48 PM

I'm with Jon on the CL thing. Maybe another idea is getting ahold of a tech school or something, and have the teacher have the students build it. Tell 'em you'll cover the cost of materials!, and that you would be happy to hear about some design advice if he had any...

David DeCristoforo

07-28-2012, 6:00 PM

Jeff sounded like it was hard for him to turn it down. But he mentioned some promises he had made to his wife and those would, of course, have to take precedence. So far I have contacted the welding shop up at UCD, placed an ad on Craigslist and searched Craigslist for welders. No action on the UCD thing although I did talk to one guy who said he "could do it but did not have the time". Tow guys contacted me from the CL ad but they seemed totally baffled by the thing and one asked didn't I "have a trailer hitch or something that needed welding". There's also a guy nearby who does "artistic" metalwork and I have a call in to him.

I'm sure I'll get this part sorted out. It's the last "big hurdle" to getting this thing running. By the end of next week, I will have the entire drive system done and at that point I'm going to want to try it out. I may have to yield to temptation and fall back on that "make shift" arrangement Scott H. mentioned, at least for the time being.

I'm not too keen on trying to make it out of wood. I had a bad experience with a similar setup some years back that left me firmly convinced that steel is the only way to go!

Kathy Marshall

07-28-2012, 11:30 PM

David, are you going with a free standing tool rest? Don't know why I didn't think about it until now, but I have a Delta outboard turning rest and it looks like it would be fairly simple to duplicate. I'll take some pics tomorrow. I think you could probably do it all yourself by just bolting it together.

David DeCristoforo

07-29-2012, 2:55 PM

I'm trying to avoid, if at all possible, any kind of "freestanding" setup. But, if I don't find a maker by the time I have this thing all ready to go (probably another two weeks yet) I may yield to the temptation!

Mike Cruz

07-29-2012, 3:33 PM

DD, they've been selling on Ebay for $200-300...

Kathy Marshall

07-29-2012, 3:39 PM

This is the Delta outboard tool rest. It's pretty heavy, weighs about 60 lb. If you wanted to make your own, you'd just need to come up with some kind of base. The upright pipe is 2 1/4" OD, length would be whatever you need to get the tool rest in the right height range. I took off the cap that holds the tool rest (takes a 1" post so any of your current rests would fit).
If you want to give it a try, or at least an interim solution until you get a permanent one fabricated, I'd be happy to send you the cap, then you'd just need a pipe with the right threads, and a base, and you'd be up and running. Just send the cap back if/when you get a permanent setup made.
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James Combs

07-29-2012, 3:51 PM

Sometimes we all need a smack in the head! When I woke up this morning, I remembered that I still have a spindle that I had made years ago to jig up a faceplate to turn some radiused crown moldings. I dug it out this morning and it's perfect for a jackshaft and even has an 8" sheave on the end! All I'm going to need is two flange bearings, two pulleys and some belts. I can pick those up locally in the next couple of days.
Here is what the final drive setup is looking like at this point. All of the speed ranges are based on not running the motor below 800 RPM.

http://www.daviddecristoforo.com/Misc/monster_drive_config.pdf

Dave, just curious but why are you considering a jack shaft instead just using two 3or4 step pulleys, one on the motor and one on the spindle? You can get the same speed ranges assuming appropriate pulley sizing. Given similar motor speeds versus spindle speeds torque will be the similar in either setup. The only difference in torque will be the loses inherent in the extra belts and bearings of the jack shaft set-up. Of course the question is mute if the motor and or spindle shaft is not long enough for the thicker step pulleys. This may have already been mention but if so I must have missed it someplace.

David DeCristoforo

07-29-2012, 4:09 PM

"...why are you considering a jack shaft instead just using two 3or4 step pulleys..."

I'm trying to get the spindle speed down to 200 RPM while at the same time keeping the motor RPM between 800 - 1,000. With a 6' pulley on the spindle and a 2" on the motor, the motor speed would have to drop down to 600 RPM. So far i have not found any multi step pulleys with a large diameter of over 6". So the jackshaft arrangement seems like a good solution. Plus, I already have most of the necessary pulleys on hand and will not have to buy any step pulleys. Good quality ones with a 6" large diameter and a 2" small diameter are not cheap and right now, I am!

David DeCristoforo

07-29-2012, 4:11 PM

"I'd be happy to send you the cap..."

That's a very generous offer. I would consider taking you up on it but I'd be afraid I would never "get a round tuit" when it came time to send it back!!!

David DeCristoforo

08-01-2012, 5:43 PM

"For whatever reason, the 1.5hp versions of this motor are non-continuous duty cycle (according to their data sheet) similar to compressor motors. I don't know what the derated duty cycle is but this may be a show stopper for you."

I spoke to the people at Dynamotor yesterday about the non-continuous duty rating on the larger motors. The explanation was that these motors are fan cooled. They also have thermal overload protection built into them. If the motors are run under load at slow speeds for extended periods, they can get hot enough to trip the overload. They explained that they are building a larger motor with a fan that maintains a high RPM regardless of the motor speed and these motors will have a continuous duty cycle rating. They also assured me that running the motor under load at 800 RPM or higher should not cause the thermal overload to kick in. Since I have worked out a way to keep the motor at 800 RPM and a spindle speed of 200 RPM, it should work out fine.