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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Mon Jul 12, 2010 2:08 pm 
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Hi Chris,
Don't worry about the table adapter being off, that's just a minor inconveniece. Instinct will tell you to set the angle at 45 degrees and everything will line up. Don't do that, rather leave the angle free, with the table adapter in the quill, loose, without the dop stick attached. Lower the table adapter onto a flat lap and tighten the table adapter once it is radially true to the lap. Then raise the faceting head up until the adapter is parallel to the lap, then tighten the angle setting. After that there may be a little fine tuning required but you will have a starting point.

I notice a small difference between your faceting head and that of the vendor. Your quill pivot is set on machined metal inserts screwed onto the brass holder, while the vendors picture show the pivot mounting machined into the brass holder.While this has no doubt contributed to your height dilemma it may be to your advantage as at some stage you can have a set made up with round holes to accomodate the shaft size and not have to worry about the quill trying to jump out on you while using lower angles.
Every cloud has a silver lining.

Sean.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Mon Jul 12, 2010 3:55 pm 
Thanks Sean fpr your reply!

I'm not worried about the table adapter being off, but rather the dop stick in it, as when I "made adjustments" to tthe table adapter, it was to fix an improperly drilled hole where the dop stick fits.

When you looked at the hole from the top, you could see equal halves of the circle shape on each side of the long rectangular gap (the space you can tighten with the screw to clamp the dop stick into the table adapter), but when you looked at the bottom of the table adapter, the part where the dop stick protrudes and makes contact with the cutting surface, you could see that one half on the circle of the drill hole looked even, while the other side was not as big of a circle shape, if that makes sense. So what I had to do was manually bore out the one half of the dop stick hole, on the bottom side of the table adapter.

I put a ruler along the table adapter, and measured with my digital calipers the distance between the ruler and the dop stick where it first comes out of the table adapter, and then compared to a similar measurement from the ruler to the end of the dop stick where the gem mounts, it was almost totally equal, so I think the dop stick will mount in there giving an exact 90 degree angle (zero degrees actually) as it should. Hope all that made sense...lol.

I'll probably have to make some adjustments when using the table adapter, but once I know which way the table adapter is naturally skewed, I will know to automatically make the same adjustment each time I polish a table.


You know, I NEVER noticed that my faceting head was different than that of the vendor's picture!

I must have looked at it a thousand times and never noticed those 2 metal holders where the quill rests in it.

Those 2 steel holders are what I was considering putting a cover over top, to ensure that they do not pop out of place when in action. I cannot see any reason why I would need to remove the quill on a regular basis do you? (other than if I were in a factory setting and were to hand my incomplete work off to the next guy who is polishing the next step of all the stones or something like that in an assembly line)

I was just going to put a small piece curved metal up against the bare part of the exposed shaft, and then fill that gap with JB weld, and then shave it all down on the top and sides all nicely, and then mount a small rectangular piece of metal to cap the top and hold it all in place. i love that JB weld stuff, it's like making pottery with steel...lol

Thanks again for your advice!

:)


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Mon Jul 12, 2010 4:36 pm 
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I'll probably have to make some adjustments when using the table adapter, but once I know which way the table adapter is naturally skewed, I will know to automatically make the same adjustment each time I polish a table.


That is often the case anyway, if the adapter was not made on the most modern equipment. A conventional Bridgeport Milling machien, for example, will not read much closer than 1/10°, and that is nowhere near where the table operation has to be. So adjusting index trim and angle is common.

Quote:
I cannot see any reason why I would need to remove the quill on a regular basis do you?


That was a "feature" of the original design, and has the good point of making the stone easier to inspect..it kind of bridges the gap between the mast-type machines and the Raytech-Shaw types. You are not supposed to be using the kind of forces in faceting that would cause the quill assmebly to jump out of the trunnions, anyway. You could always make ball-bearing pillow blocks for it in the future. This would eliminate slop and wear.

Essentially, the purchase gave you finished castings with which you could build a faceting machine, so it was a good way to learn the mechanics, and end up with a machine, without spending a fortune, or taking the chance of buying a used something, worn-out and rusted, that was found in a barn somewhere. Not a bad deal at all.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Mon Jul 12, 2010 7:06 pm 
Hey Gearloose,

Thanks for that uplifting piece of advice, I think I like your attitude and approach to things, in fact, I think we must share similar reasoning.

Most people will not see the learning curve aspect of a situation like this, but only see the "inconvenience:" of it all when they want to just jump in and start faceting.

Actually, I "prefer" challenges like this, it's kinda like owning a ford minivan (which I do, don't laught too hard, F-found O-on R-road D-dead, ......F-ix O-or R-repiar D-daily, .........F-fast O-only R-running D-downhill .....haha), meaning that I PREFER to have encountered problems and KNOW how to address and fix them immediately, rather than be clueless, and have to depend on someone else to fix it!

I usually hear negative things because I haven't splurged big bucks for some serious entry level kit of some type when I newly get into something, as most people that are deep into a hobby or industry would not think of having to have a hassle with something, and therefore regard anything less than perfect as junk, I find the same attitude with opals, alot of people won't bother hunting for good deals in a bargain parcel of rough, they want to pay more, and be ASSURED a good value in what they have purchased, little do they realize that they just PAID more to ensure that!

I don't mind purchasing a hundred buck parcel of opal, and taking the time to dig through what the sorters or miners may have missed, and I don't mind shopping at value village either...lol.

There are times however when you do pay the big buck for a decent parcel however, I just know "when" those times are, hehe.

Anyhow, I've looked at your webpage, and realize that you are a person who is definitely MORE than a hobbyist, so hearing from you that I've made a right move in purchasing what I did is a complement, thank you for that!

There WILL be a time in the very near future I'm sure that I will be upgrading to a more serious setup, once I have exhausted the limitations of what I'm building now, and in the meantime, I'm definitely coming to a much better understanding of what makes a good and a BAD faceting setup, what features are important, and which ones are not, and also realizing that for the hardware, faceting machines are VERY over priced for what you are getting for the money. If it were any other kind of precision device, 2 or 3 grand would go a LONG way!

Thanks again for your advice and guidance, I do VERY much appreciate it, and by the look of the gems on your page, very much respect anything you have to say about the faceting industry, they are awesome!

Chris ;)


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Mon Jul 12, 2010 9:02 pm 
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I usually hear negative things because I haven't splurged big bucks for some serious entry level kit of some type when I newly get into something, as most people that are deep into a hobby or industry would not think of having to have a hassle with something, and therefore regard anything less than perfect as junk, I find the same attitude with opals, alot of people won't bother hunting for good deals in a bargain parcel of rough, they want to pay more, and be ASSURED a good value in what they have purchased, little do they realize that they just PAID more to ensure that!


When I started faceting I was a teenager who worked on a farm after school, so I made building my own equipment a hobby in itself. Until the Internet I had never seen a "Real" faceting machine in my life, up close.

It's not for everyone, though, and could even be of dubious gain; When we grow up and have real jobs, it takes fewer hours to earn the money to simply buy a new machine in a box, than it does to make the machine and get it just right.

Likewise, I would also pick through bags of incoming opal that would require a lot of work. (Until Joe Stachura's pity ran out and he put a stop to letting me pick through it...THAT did not last long at all. ) That was a LONG time ago now. Bulk commercial cutters could not use the material, because it was too labour intensive.."Following the Fire", and avoiding cracks and potch.

(Quick Yankee to HC Accent Shift)
There is also the peculiar problem we have in the part of the world where we live; It involves going to the shore and picking mussels off the rocks before the seagulls get them, Eh?
:P


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 12:15 am 
I know what you mean about the financial feasibility of an operation, it makes sense that if you cannot make your labor hours turn into adequate profit for your business then you'd best not be in business!

It's kinda like here in Nova Scotia, where a huge area of the Bay of fundy is rich in gold gems and mineral deposits, and was all bought up by a huge gem company back in the 1800's when they had big dreams of a large scale extraction of profitable material, but in the end, they gave it up and didn't bother mining any of it as their initial investigations were too hasty, and there just wasn't enough material to make a "commercial operation fly, but it's a goldmine for gem collectors and hobbyists who walk the shores of "Amethyst cove" picking up huge chunks of amethyst, garnet, agate and other gemstones that even just was onto the shore, or fall out of the cliff-side onto the beach after a harsh winter storm. I have alot of that material right here on my desk, very pretty stuff!

I have a question that I'm sure you know the answer to Gearloose, since your obviously VERY familiar with faceting machines.

What is the "typical" horsepower motor that the faceting machines have in them?

The reason I ask is because i have a choice of connecting the one speed 1725RPM AC motor via a big pully and belt, as I would with a heavy duty flat lap of rock saw, OR powering the faceting lap with a much smaller DC motor, which is speed and direction controlled, and i think well matched for this type of system, only the HP is quite a bit less.

i was wondering what the minimum HP you would want to use with a faceting machine like this, I can't see it requiring near as much HP as a powerful grinder or flat lap needs to be, as your not really removing all that much material, and also, the preforms are still going to be made on my heavy duty flat lap machine.

The motor is a Baldor DC brush motor, which is rated at 0.04TE HP (I'm not sure what the "TE" means in the rating on the sticker, are you?) at 0.25 AMPS, and it is a 1723RPM motor. It is controlled by a separate DC controller circuit board specifically manufactured to speed control this particular motor by Baldor, and has a potentiometer for precise speed control, and a FWD/REV switch, which comes in handy.

I just wonder if it is enough HP for a faceting job, I know that when it is powered up I certainly cannot stop the shaft of the motor from turning with my fingers, it feels very strong actually.

It would just be nice to put this setup to good use if it is powerful enough for the job, and it's features are probably exactly what I would need, it's just a matter of if it has enough torque for the job I guess.

I see those little inland entry level faceting machines for sale (which are expensive for what you get!) and think they probably have an even less powerful motor in those, and it is probably all plastic too!


I'll post a pic of the motor below so you can see it.
Thanks
Chris ;)

Image

Image


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 5:57 am 
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Quote:
What is the "typical" horsepower motor that the faceting machines have in them? i was wondering what the minimum HP you would want to use with a faceting machine like this, I can't see it requiring near as much HP as a powerful grinder or flat lap needs to be, as your not really removing all that much material


For direct drive, 1/8 HP is a real minimum. 1/5 + is preferred. Multiply the nameplate voltage and current to get peak Watts. The .25 A motor you mention below is probably a 90VDC motor because it is equipped with that KB controller. 22.5 watts. A horsepower is about 740 Watts. The "TE" rating means "Totally Enclosed".
You can use a smaller motor and run it till it screams with belt reduction to give you the needed torque, but I'd forget this particular motor.
A machine that slows down in response to load is frustrating-and you never know what actual speed you are cutting and polishing at.

Quote:
The reason I ask is because i have a choice of connecting the one speed 1725RPM AC motor via a big pully and belt,

Too bulky and heavy. Single speed. Don't bother. Everybody uses an old washing machine motor. Once.


Quote:
It is controlled by a separate DC controller circuit board specifically manufactured to speed control this particular motor by Baldor(Nope.), and has a potentiometer for precise speed control, and a FWD/REV switch, which comes in handy.


Make sure any FWD/REV switch use has a Center OFF position. If you ram it into reverse while the lap is spinning, it's usually the end of the controller.

See the big ceramic white resistor? Those can be changed to "program" the controller for a variety of motor sizes. Baldor buys them from KB. They are off-the-shelf and are on EBay all the time. This particular series may not run a large enough motor for your needs.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 9:56 am 
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If I were building a BIG faceting machine, maybe built into a workbench, I'd scrounge a motor and possibly the controller from a discarded treadmill. "Possibly" because the controller is sometimes what breaks on these machines. Lots of power, reasonably compact.

Actually, now that I think about it, the motor would be around the same size as the one on Graves' Mark I base.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 10:29 am 
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If I were building a BIG faceting machine, maybe built into a workbench, I'd scrounge a motor and possibly the controller from a discarded treadmill. "Possibly" because the controller is sometimes what breaks on these machines. Lots of power, reasonably compact.


They are pretty big, about 4" in diameter+ and nearly a foot long, for the Pacific Scientific models. They are typically in the range of 1/3 to 3/4 HP, but the kicker about these is they are 3600 RPM motors, whose armatures are wound very differently than most other types, with much lower impedance.
A proper controller will cost about $130.00. The PWM controllers in the treadmills are kind of the Amoeba of controllers, but suitable for a treadmill.
Another issue is that they are not Continuous rated.
The real design objective for a treadmill, as we all see driving around locally, is that they are bought, used a few times, and left at the curb for a long time.
You can use one, but they need to be derated. The speed/torque curves are not really right for faceting, as their low speed efficiency is not good.
EBay is well stocked with these motors, often being sold as "Wind generators" in an effort to get someone to buy them for some reason, any reason. I have a few I have tried.
Better a smaller more appropriate motor. You CAN use one of the many 90V 1/2 HP nominal 1750 RPM motors for direct drive.
Avoid lower voltage motors unless you want to go hunting for transformers and diode bridges to add to the circuit. As voltage lowers, currents increase to get the same HP. This is why cars switched to 12 Volts from 6, and military aircraft are 24V. It saved lots of copper.
Avoid the "scooter" motors Ebay is infested with, 12 V or 24V. Not only are they toys with bronze bushings with junky cadmium plated stamped housings, they need outrageous currents because they have four brushes with parallel wound armatures.
Avoid motors other than Permanent Magnet types. Field windiings are last century. The Real Controllers furnish 50VDC for energizing the field, but it's still two more wires and lower efficiencies.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 4:29 pm 
Well, that pretty much puts me in the original position that I was in!

I could not find a motor that was CHEAP and easily accessible to me, I could order one that was VERY expensive, or I could buy one on ebay for a reasonable price, but still not CHEAP enough for me to really afford right now.

That speed controlled setup that I posted pics of is one I purchased off ebay to put into a cabbing machine, but upon receiving it, i immediately noticed that the size of the motor was only .04HP, and NOT the 1/4HP they advertised it as, so I was stuck with it, and a huge cuffuffle ensued.

I looked for a treadmill controller for a LONG time, but could not find one that was cheap, as with the $60.00 - $80.00 plus in shipping to me here in Canada, it started to get way up there in price, so I just said the heck with it.
I know this motor is not "ideal", I was just hoping that it would temporarily "suffice" until a "proper" HP motor happened my way.

You know how it is, when your looking for something, you NEVER see it, and as soon as you stop looking, you see that thing EVERYWHERE!!

Unfortunately right now, the ONLY option I have is the one speed reversible 1/4HP furnace type motor which is 1725RPM, OR the speed controlled wimpy motor that I posted pics of, given the choice of the two (although neither is proper or ideal) which one WOULD you pick if you had no other choice?

I will buy an upgraded motor when I can afford one, and if I can use the same controller as you mentioned by simply upgrading the resistor, then no problem, I'm actually an electronics tech by trade, and have a large assortment of electronic components, including large ceramic power transistors at my disposal, I just need to know the correct resistance and wattage for the motor size if I understand you correctly.

The motor that actually came installed in the "Diamond Demon" Crysalite vertical dual flat lap that I have is also a baldor motor, an older one, which is a whopping 10,000 HP motor, and is connected to an external speed controller. That motor is only a 1/15HP motor, and it does slow down a bit when you apply pressure to the lap with a gemstone, and you have to constantly have your finger on the speed dial to compensate and kick it up a notch when it slows down, because as it has pressure applied to the wheel, it needs more voltage to make it spin at the same RPM you originally intended it on doing, and as soon as you take the pressure off, the speed increases like crazy, so you never really know what RPM's your polishing at! It sux actually!

I know a similar situation would arise with the smaller speed controlled motor unit I have, so i was wondering if it was better to have a very strong constant 1725RPM, or a wimpy fluctuating but speed controlled and reversible setup.

Again, neither is ideal, but one of them will have to do until I can find or afford something else!


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 5:01 pm 
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Quote:
Unfortunately right now, the ONLY option I have is the one speed reversible 1/4HP furnace type motor which is 1725RPM, OR the speed controlled wimpy motor that I posted pics of, given the choice of the two (although neither is proper or ideal) which one WOULD you pick if you had no other choice?


If a gun were pointed at me to force a decision, I would use a SEALED [url]ball bearing[/url]arbor and two 3-stepped pulleys for a VBelt drive with the 1725 RPM induction motor and sell that .04HP on EBay or otherwise dispose of it. Or use it for a fan or something, I guess.
I would not use a 1725 fixed speed lap for faceting in a direct drive application. Way too fast. I am an animal, and do not use those speeds.

You COULD continue shopping for a cheap PM DC motor around 200W and control it with a Variac and a 6 Amp diode bridge. That will give you some basic speed regulation cheaply. When the armature slows under load, reactance+ Back EMF decreases and current rises.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 7:16 pm 
I can tell you've been doing this for quite awhile!

There are things that I also have been doing for years, and wouldn't even think to ask those rudimentary questions about the basic fundamentals, you just know them, so it must be interesting for you to have to think about these things, and have to explain basic concepts to someone when they are all 2nd nature to you....lol.


There are 2 kinds of things that I will build, things built from items laying around the house, and things that I build "properly", carefully planning and purchasing components until I have everything I need on the bill of materials, and then I build it, at least the 1st revision of it...lol.

Home made things are rarely factory perfect after a first build, and usually alot of modifications come with after thought, but hey, that's exactly the same as all production houses in electronics, there is NEVER a 1st revision that just IS the product, just ask Bill Gates, windows STILL doesn't work right!
So, I don't put "too" much pressure on myself to get things perfect, just relatively functioning correctly, that's all.

What I'm building right now is "type 2", the one that is built from things laying around the house, although I have gone out and purchased some metal for the framing to bolt together, so that I can properly build a mount and a deck for the arbor and everything to mount on, that way, I can fine tune the height on all 4 corners of the arbor mount, to ensure I can level both the mount for the mast base of the faceting device, as well as leveling the actual angle of the cutting surface separately. It won't look like a machine shop built it, but it also won't look like it's a piece of junk either!

The point is, all of that stuff is permanent, whatever motor I mount on this thing to drive it is temporary, and will disappear the second I "acquire" something better to turn the arbor.

What do you recommend for a proper speed for faceting? With pulleys I can basically make anything from 1725RPM, I can slow it down pretty good with the large and small pulleys that I currently have in my box of tricks, I just don't know what the preferred RPM is for faceting, I was "assuming" it was around 800 - 1000 RPM, am I correct?

I've noticed that the manufacturers of faceting equipment rarely post ANYTHING about the specs of the motors that drive their equipment, it's as if the "know" that if they tell you, they will lose business, as you will just go build your own unit!

I have not seen ONE lapidary unit or faceting unit that posts the speed (RPM's), HP, amps, or anything about the motors that they use, they only say things like "speed controlled", or "reversible motor", but NEVER the RPM or the HP of the motors they use!

I have a pretty heavy duty sealed bearing arbor that has a 1/2" threaded shaft coming out of it, and the shaft appears to be about 5/8th or so in the bearings, so it's pretty heavy duty, probably more geared towards a slab saw or something, but it spins nice and even, with no wobble at all when I mount a lap on it and spin it, in fact, it will just keep turning for about 3 minutes before stopping if I give it a spin with my fingers, so I know the ball bearings are good in it.

I seen an arbor unit specifically made for a faceting unit for sale at Lapidary Discount for only around $57 bucks or so, and they have another one that says it's just for a lap for around $45, if this arbor doesn't work right, I'll just purchase one of those professionally made ones, I think Covington makes it.

It's located here:

http://www.lapidarydiscount.com/Arbors.html

They seem to have very cheap prices, but also don't seem to have an internet tech support address or sales address, only a phone number to call in orders.

Thanks for your advice on the motor! I think no matter what, there is no getting around it, those things just don't fall off of trees and into people's laps for nothing, if you want the right motor to make a unit like this, your gonna have to PAY for one.
;)


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 8:46 pm 
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What do you recommend for a proper speed for faceting? With pulleys I can basically make anything from 1725RPM, I can slow it down pretty good with the large and small pulleys that I currently have in my box of tricks, I just don't know what the preferred RPM is for faceting, I was "assuming" it was around 800 - 1000 RPM, am I correct?


You will hear varying advice on that as it is operator and technique-sensitive and also varies with laps and gem rough. Truthfully, I would say 0-600 RPM as a basic. But that is just me, my shop, my faceting head.

Actually, if you go to flea markets and yard sales, one just may fall into your lap-you can never tell. For example, one of the best motors I ever encountered came from some kitchen appliance. It was off whatever it was made for, so I do not know what the thing was really used for. But a universal AC/DC motor can be controlled with a variac or even (ugh) a rheostat.(1920's retro)

But bear in mind a sign seen in shops:

|GOOD|FAST| CHEAP|
Choose any TWO.


You can take a year and build it well on a budget, you can build it this week cheap, you can spend a lot of money, but you do not get all three.

Remember, YOU are going to have to USE this thing.

The Covington arbors are fine. They have been around for ages.

Read what that ceramic white resistor is labelled on the KB controller; It should have a HP Ident on it and a resistance. I have an idea.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 8:56 pm 
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I could not find a motor that was CHEAP and easily accessible to me, I could order one that was VERY expensive, or I could buy one on ebay for a reasonable price, but still not CHEAP enough for me to really afford right now.

That word in the context of faceting is a noble goal, but of all gemcutting techniques, faceting has the highest entry barrier.

Flying is expensive.
I could probably build a 2-place ultralight aircraft from beach umbrellas, a lawn chair, and a 2-stroke used snowmobile engine for $300, but suspect I may have trouble getting passengers. There ARE limits on savings.


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 Post subject: Re: New to faceting, need help mounting mast!
PostPosted: Tue Jul 13, 2010 9:36 pm 
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Gearloose wrote:
They are pretty big, about 4" in diameter+ and nearly a foot long, for the Pacific Scientific models. They are typically in the range of 1/3 to 3/4 HP, but the kicker about these is they are 3600 RPM motors, whose armatures are wound very differently than most other types, with much lower impedance.
A proper controller will cost about $130.00.


The two that I had were 4" x 7 1/2" by Forehouse Co. Ltd. Label says

Mode DC P.M. HP 2.25 Amps 10 Volts 90
Rotation CW RPM 4700 Duty Treadmill

I sold one to a fellow who said he was going to use a Variac and a Radio Shack 10A bridge rectifier.

DC motors are small for the power. The old Bausch & Lomb Building, on the Genesee river, had DC elevators powered by a special feed from a Rochester Gas & Electric plant beside it.


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