Replies

1. 
   Joby | May 06, 2007 01:42pm | #1

   A lot of auctions that I have seen that have three phase equipment may also have a few converters as well. Check and see. If not, check eBay for one. I got mine very cheap to run a bandsaw I got at auction.

   Good luck.

2. 
   Tony Z | May 06, 2007 02:26pm | #2

   Check the "Old Wood-Working Machines" Website for ideas, thoughts and different methods.

   Several years ago I picked up a Unisaw, a Powermatic Model 90 lathe, a Delta 8" grinder, a Delta drill press and Delta 7" grinder.  Total cost was $1,100.00 and all but the grinder were three phase.  I "putzed" around with the idea of a phase converter and researched both static and rotary types but since the equipment was all duplicate of what I already had, I opted to take a long term approach and change out motors instead, and changed to single phase 220 volt.  I sold the drill press and grinder and made enough for motors for the lathe and jointer.  The unisaw is patiently waiting it's turn, but in the end I'll end up with three pieces of excellent condition, old iron that will easily last several decades or more.

3. 
   TomW | May 06, 2007 02:57pm | #3

   I went with a rotary converter and have it set up to turn on automatically for whichever machine I am using. Other than a 1 second delay after hitting  the switch you would never know it is run on 3 phase. 

   Certainly opens up options for machinery and 3 phase motors can be picked up pretty cheap.

4. 
   JeffHeath | May 06, 2007 08:09pm | #4

   Bob

   I have several 3 phase industrial woodworking machines in my shop run off of a rotary phase converter, including my 12" jointer.  I built my own, but ebay has several different mfg.'s of rotary phase converters, and a few have excellent and easy instructions for wiring into your shop.  I wouldn't hesitate getting 3 phase equipment if I were you, as the old industrial machinery is so much better than the cheap garbage  passed off as new machinery today.

   Jeff

5. 
   [email protected] | May 06, 2007 09:49pm | #5

   At a former employer, we used variable frequency drives (vfd) to convert from single phase to three phase on pump motors up to 10-hp.  It isn't as efficient as three phase so the operating cost is slightly higher.  But, we got the advantage of soft start and stop, which greatly simplified the hydraulic surge protection.  And, didn't have to run twenty plus miles of three phase.

   A vfd, controls the motor speed by doing exactly what the name implies, varying the frequency, while maintaining the voltage.  If the motor is free spinning at 1200-rpm and you put a load on it, the amperage will increase to hold the speed constant.  Output frequencies from 20 to 240-hz are common, with some having lows of 5-hz, and highs of over 240-hz. 

   I just did a check on ebay.  There is a buy it now listing for a Hitachi, rated at 3-hp, single phase 240-volt in, and three phase 240-volt out, with a frequency range of 0.5 to 360-hz, for $285 with free shipping.  The listing says he has 100 of them.  This gives out put speeds for a 3450-rpm motor, from about 30, to 20,000-rpm, while maintaining constant torque.  I'm not sure what is going to happen to the rest of the drive train, i.e. belts and bearings, if you run it that fast, but it is intriguing.  You could put one on a shaper, and run router bits, at 20,000 rpm.  And, one on a drill press would get rid of the stepped pulleys. 

   There is another listing for a 5-hp unit, buy it now is $549 + $25 for shipping. 

   The cost tends to go up exponentially with the horse power rating, but depending on how much you spend on the three phase equipment, it could still be a very cost effective solution.  And, the soft start, variable speed feature is a real bonus. 

    

1. 
   RickL | May 07, 2007 11:48am | #6

   Look at VFD's from http://www.factorymation,com Great prices.

2. 
   philip | May 07, 2007 11:56am | #7

   Just noticed, on passing by:-
   "You could put one on a shaper, and run router bits, at 20,000 rpm."
   I think not- way above max speeds of bearings found on 30mm shaft.Philip Marcou

1. 
   philip | May 07, 2007 03:32pm | #9

   Here are some facts to support what I said earlier, now that I have confirmed their accuracy with my machine manual and the SKF bearing catalogue:
   Top bearing -designation 6008
   Lower bearing- '' 6206
   Maximum permitted speeds with grease: 10000 and 9500rpm respectively-or 13k and 12k respectively with oil.
   I have a typical medium industrial shaper with 30mm shaft.
   Shapers are not fitted with precision high speed bearings-they are not required because, amongst other things shapers are not to run at speeds of much over 10000rpm- maybe 12000rpm at most. The bigger the shaft the bigger diameter cutter heads therefore no need for huge rpm's- unlike routers.
   With reference to routers: one of the reasons why they are always killing bearings is that the top speed of a typical router can be over 25000- my Elu MOF 96 has bearing designation 6003 at lower end- max speed is 19000...well under top speed.
   How is that for an off the subject deviation?Philip Marcou

1. 
   Scrit | May 07, 2007 04:23pm | #10

   "Shapers are not fitted with precision high speed bearings-they are not required because, amongst other things shapers are not to run at speeds of much over 10000rpm- maybe 12000rpm at most. The bigger the shaft the bigger diameter cutter heads therefore no need for huge rpm's- unlike routers."

   I'd agree wholeheartedly with that - a typical 100mm (4in) diameter rebate block cutterblock running at 7,200rpm has a peripheral speed of circa 86mph - to get that peripheral speed out of a 25mm (1in) router cutter would require a spindle speed of just under 30,000 rpm.......

   Scrit

2. 
   [email protected] | May 07, 2007 05:26pm | #11

   Guys, I was just noting that the capabilities of any machine would be greatly enhanced by the ability to control the motor speed, which is a side benefit to using a vfd to convert from single phase to three phase.  It lets you get rid of the stepped pulleys and makes speed changes easy. 

   I am not advocating anyone spin a shaper at those kind of speeds, and wouldn't consider it, with out first checking the capacity of the components to handle it, and modifying as needed.  And I do mean "as needed". 

   I would be more concerned with the dynamic balance, belts and pulleys, and the bearings and balance of the motor, than the spindle bearings though.  The spindle bearings would be relatively easy to upgrade, the rest of the components could be very difficult, if not impossible.  First thought is the belts would stretch and come off, etc. 

   There are bearings available for the spindle that would handle the rpm load, but if the machine isn't balanced well enough to spin that fast the load from the imbalance will hammer things apart in short order. 

   That said, if I had a shaper and a vfd that would let it double the rotation speed, (depending on what router bit you used, you wouldn't necessarily want to even double it), I would investigate the cost of modifying it to handle router bits for the rare occasions I might want to use one of the profiles that would be expensive or hard to procure, as they are not stock items and would have to be custom ground.

1. 
   Scrit | May 07, 2007 07:43pm | #12

   "Guys, I was just noting that the capabilities of any machine would be greatly enhanced by the ability to control the motor speed, which is a side benefit to using a vfd to convert from single phase to three phase.  It lets you get rid of the stepped pulleys and makes speed changes easy."

   Well I'll respond with a bit of practical experience from being an industrial router user (pin and CNC). Modern CNC routers use inverter drives (VFDs) to control the speed, however they suffer greatly from torque loss. Before VFDs came in (really from the late 1980s) we used to use mechanical frequency changers - literally a motor hooked up to a multi-pole alternator - which would generate either two or possibly three different frequencies generally corresponding to 12,000 / 18,000 / 24,000 rpm (and you didn't run at 24k all the time because your brearings simply wouldn't last). The motors we were driving were often rated at 2 to 3-1/2 HP continuous, or 6 to 10 HP peak. In order to achieve the same level of performance we've seen CNC high speed spindles go from 5HP to 7.5HP, to 10 HP and above partly because the VFD motors lack the torque required in heavy cutting, especially if they're loaded up with spindle moulder-type RT tooling and spinning at lower speeds - and the trend towards larger diameter tooling meand that we are now running tooling at much lower speeds than formerly. Perhaps we have an electronics buff in the audience who'd like to put a technical explanation to this, but my experience of VFDs is that at low motor speeds in particular they lose tremendous amounts of torque and become prone to stalling.

   "There are bearings available for the spindle that would handle the rpm load, but if the machine isn't balanced well enough to spin that fast the load from the imbalance will hammer things apart in short order."

   The point about a spindle moulder (shaper), though, is that it is designed to use a completely different type of tooling with a larger diameter. On spindle moulders (shapers) the cutter velocity is derived from using larger diameter tooling, generally in the order of 100 to 200mm (4 to 8in) at a much lower speed than a router. The fence layout on the machines favour ring fence (template) work and straight fence (edge profiling) work. Converting a spindle moulder (shaper) to run router tooling seems to be a total waste of time because the machine is more effectively used with the appropriate tooling - and spindle tooling is normally unsafe to use at extremely high speeds because it is not rated for that due toi the larger diameter

   "That said, if I had a shaper and a vfd that would let it double the rotation speed, (depending on what router bit you used, you wouldn't necessarily want to even double it), I would investigate the cost of modifying it to handle router bits for the rare occasions I might want to use one of the profiles that would be expensive or hard to procure, as they are not stock items and would have to be custom ground."

   With Euro-style replaceable tip tooling it is often cheaper to have a set of knives ground than to buy a stock router cutter. Bear in mind you will need to spend several hundred dollars having a new top piece made to hold something like ER25 or ER32 collets in which to mount your router cutter and for that amount of money I could buy a Euro block and about 6 to 8 sets of off the shelf profile knives. I don't think your approach makes economic sense, especially as there are inverted routers such as the Onsrud/Delta out there which work as a pin router or a router table and have collets to hold router tooling from the get go.

   Scrit

2. 
   [email protected] | May 07, 2007 10:59pm | #13

   Scrit, this thread started out with a question on whether it makes sense to bid on three phase machinery at auction if you don't have three phase power at the shop.  And, the first three or four posts were about getting single phase converted to three phase with rotary converters.  I surmise from the lack of available three phase power, these are hobby or small commercial shops, outside of normal industrial areas.  

   The vfd, is one of the methods available for converting from single phase to three phase.  At current prices it is also probably the more economical on machines of 3-hp and less.  I know that with many vfds there is a loss of torque at the low end, (the newer ones are better).  But in most instances home users would be overspinning and not underspinning.

   My impression of the op's situation, and mine, is that we don't have budget to buy new large machines, and are hunting for bargains.  I'm a hobbyist, and for me the footprint on the floor is also a major consideration, particularly when the machine is a piece of big iron that isn't going to be readily portable. 

   And, yes, it would cost several hundred dollars to have a collet machined to accept router bits.  Have you priced a Porter Cable 7518, or any of the other quality 3+hp routers?   They run $300+.  Add to that the cost of some kind of lift, a decent fence, and building a table to mount it in, (which will eat more space), and you are rapidly pushing $800+.  Before I spend that money on a router table, I will step up to a small shaper.  I am somewhat aware of the cost of shaper cutters, and that you can buy a cutter head with replaceable/interchangeable knives, (I've been looking at them in the wish books for years).  But knives are not readily available in most small to medium sized towns, and sometimes you don't have the five days it takes to ship things in.  The only hardware store where I live is owned by a guy who's hobby is woodworking.  He has as good of selection of router bits, as the two Woodcraft stores I've been in.  I can buy most router bit profiles readily. 

   I understand fully that the tip velocity is what makes a clean cut, and that a larger diameter cutter needs to turn slower to keep the tip velocity in the range between a bad cut, and burning up the cutting edge. I also know there are better machines out there for many of the tasks I and others are forced to do with machines that are less than ideal for the task at hand.  Those machines also cost lots more money than I, and many others, have invested in the entire shop. 

   I'd love a big pin router, and a shaper, and the nifty wood milling machine that Grizzly makes, and a big cabinet saw, and a big band saw, and a jointer with a top the size of an aircraft carrier, and a couple of thousand feet each of several species of really nice figured wood.  If money were no object, I'd build a shop and fill it with lots of really neat big iron. 

   But money is a finite resource that I, and most other hobbyist and small scale commercial shops, have to budget and spend wisely to maximize what we can do with what tooling we do have.  Sometimes we even have to invest lots of time in building tools and equipment to do the job we need done.  We all know that there are already machines out there that will do the task, almost always to a higher level of quality than our shop built device is going to be possible of, but we don't have the money it takes to buy them and tool them up. 

   I don't know if you have seen any of the older editions of "Fine WoodWorking", back when they used to publish articles on making your own machinery.  Things like: belt thickness sanders (no guards); and  a band saw made out of plywood with MDF wheels powered by a washing machine motor; a panel saw from a modified sears table saw; a slider table from plywood, black steel pipe, and roller skate bearings; homemade t-square style fences; and, all sorts of other things that were readily available in the commercial market.  We all know there are wondrous machines that do the job.  So, why was there an interest in those articles?  Most of us can't buy commercial machines.  We have to get by with what we have, or can make. 

3. 
   Scrit | May 08, 2007 12:47am | #14

   I started a small commercial shop quite a few years back when I had less money than many well heeled amateurs so I've made do and mended quite a lot, too. There is a point about not trying to turn a sow's ear into a silk purse - or in this case a spindle moulder (shaper) into a router table - but there is also the fact that it is possible using just a $25 double ended grinder, a selection of thin grinding wheels, engineer's blue and patience to grind your own knives. Whicjh makes a conversion pretty pointless. Of course you can go off and buy a basic profile grinder (such as the Viel or if you really want to spend money a Weineg Rondamat) which will copy a template onto a cutter blank, but in a non-commercial environment all you need is to ensure that one of the cutters is sharp and the correct profile, and that the other one balances it. My notes of caution were sounded because  felt the impression is being given that it is OK to take several hundred pounds (weight) of commercial machine and up the spindle speed to the point at which router cutters will work effectively without any major consideration for the potential pitfalls.

   Scrit

3. 
   Scrit | May 07, 2007 02:46pm | #8

   "...there is a buy it now listing for a Hitachi, rated at 3-hp, single phase 240-volt in, and three phase 240-volt out, with a frequency range of 0.5 to 360-hz, for $285 with free shipping.  The listing says he has 100 of them.  This gives out put speeds for a 3450-rpm motor, from about 30, to 20,000-rpm, while maintaining constant torque.  I'm not sure what is going to happen to the rest of the drive train, i.e. belts and bearings, if you run it that fast, but it is intriguing.  You could put one on a shaper, and run router bits, at 20,000 rpm."

   What would happen is one or a combination or even all of the following, eventually:

   1. The bearings might collapse

   2. The spindle might break-up because it isn't balance to run at that speed

   3. You'd become familiar with the food down at your local ER

   High speed motors and drive trains require much better quality bearings (did you know that 24,000 rpm industrial router spindles generally have ceramic bearings?) and anything spinning so fast needs to be properly balanced

   In any case a 1in or 1-1/4in spindle moulder (shaper) generally doesn't come with any means of holding a router cutter in a collet. They are designed to use completely different tooling. You might strike lucky and get a machine which can take a replaceable top piece. But then how much is it going to cost to have a new top piece to take router cutters made?

   Modern spindles such as those built by SCMI and Panhans, etc are designed to run at up to 10,000rpm. Older machines from the thirties, forties and fifties were frequently designed to have a lower maximum speed of 5,000 to 7,000 rpm. My understanding is that part of the reason was problems of bearing life at higher speeds and also of drive belt slippage. Companies like Wadkin did manufacture special high spindles capable of running at up to 15,000 rpom as far back as the late 1920s, but the few high speed machines like that I've worked on have higher grade bearings than the run-of the mill standard spindles (the bearings still tend to run hot and suffer more from seizures). Personally I wouldn't fancy the idea of driving a model T Ford at 80mph for the same reasons I'm not enamoured of running a spindel moulder at three times it's designed speed.

   Scrit

   Edited 5/7/2007 7:58 am by Scrit

   Edited 5/7/2007 7:59 am by Scrit