Replies

1. 
   JohnWW | Mar 24, 2004 06:10pm | #1

   Dave,

   Changing speed by using different size pulleys or different gear ratios has no affect on the horsepower available to the cutting head.  In fact, if you reduce the spindle speed, the torque will increase proportionally.  In practical terms, a slower speed cutter will be harder to stall, not that you're likely to stall something driven by a 5 HP motor. 

   Pulleys do waste a certain amount of power, to minimize the loss always use the largest pulleys that will give you the speed you want and will fit in the available space.  Using linked belts will make changing pulleys go a little faster and will give a smoother running machine.

   A more sophisticated approach would be to use an inverter control and a three phase motor which would give an unlimited speed range, including higher than stock speeds,, reversibility, and braking.  If the motor is already a three phase, this would definitely be the way to go for probably under $500.00.

   John W.

   P.S.  All of my comments here apply only to DECREASING cutter head RPM, there are very real risks associated with increasing the speed beyond the machine's or the cutter head maker's  allowable maximums and this should never be attempted.

   
   

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   Edited 3/24/2004 2:17 pm ET by JohnW
   

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   Edited 3/26/2004 11:34 am ET by JohnW

   
   

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   Edited 3/26/2004 11:42 am ET by JohnW

1. 
   daveallan8 | Mar 25, 2004 07:02pm | #2

   John W.

   Thanks for the info.  The motor is single phase so I guess I will have to try changing the pulleys.  As far as stalling the motor, I did actually do that once with a freeborn raised panel cutter, so I had to make several passes to get to the proper depth.  Any advice on how to find the right sizes and fit to my motor and spindle would be appreciated.  Thanks again

   Dave

1. 
   JohnWW | Mar 25, 2004 09:14pm | #3

   Dave,

   If you can tell me what diameter pulleys you have on the machine now and whether or not you can fit a bigger pulley on the spindle I'll give you a couple of options for pulley sizes.  Hopefully the machine uses ordinary standard size pulleys which can be ordered from a number of sources.

   It is quite possible that Delta has optional pulleys already available for slowing the spindle down, you might check with them first, their customer service is supposed to be quite good.

   I'm not that familiar with Delta shapers, can you also give me your machines model number so I can look it up.  One last question, how does your machine switch between the two speeds, is it a motor control, a gear shift, or do you have step pulleys that you need to switch the belt on?

   John W.

1. 
   daveallan8 | Mar 26, 2004 11:46pm | #9

   John,

   The pulleys are difficult to measure but I think the motor pulley is 6 1/2" and spindle is 3".  The pulleys have six grooves in them and they are stepped.  There isn't much room to go bigger on the spindle, maybe 1/2" tops.  The model# is 43-455.  Thanks again for all of your help.

   Dave

1. 
   JohnWW | Mar 27, 2004 10:38pm | #10

   Dave,

   If you kept the 3" pulley on the spindle and put a 3" pulley on the motor you would have 3,400 rpm, a 4" drive pulley would give you 4,500 rpm, and a 5" pulley would give you 5,600 rpm.  The belts on your machine are poly v-belts which can be harder to locate pulleys and belts for but there are sources.  Delta doesn't offer alternative pulleys for your machine.  If the spindle pulley would fit on the motor shaft you could order a spare one from Delta and use it for a drive pulley but you would still need to get a shorter belt 

   You could also replace both the drive pulley and the spindle pulley and use a standard v-belt drive, possibly using twin groove pulleys with two belts for better power transmission.  For many years Delta made that shaper with a standard single v-belt drive set up for 10,000 rpm.

   Having said all of this, I would repeat the question asked by another poster, are you sure you need to go below 7,000 rpm?  I looked up your type of cutter and according to the source I used, at 7,000 rpm the cutter can be up to 5" in diameter and still be used safely.  Of course the ultimate opinion on safe cutter speed is the cutter head's maker so you should contact them to be sure. 

   If the cutter is small enough to be used safely at 7,000 rpm and you aren't getting a good cut, the cause of your problem probably isn't the cutter speed.

   John W.

   Edited 3/27/2004 3:48 pm ET by JohnW

   Edited 3/27/2004 3:50 pm ET by JohnW

2. 
   daveallan8 | Mar 28, 2004 10:23pm | #15

   John

   Thanks again for the info.  To clear things up I need to explain exactly what my problem is.  The problem doesn't have to do with safety.  I primarily use corrugated back or lock edge cutters which are bigger and heavier than say a 3 wing cutter.  I worked in a shop that had a 15 hp SCMI shaper and we ran everything at 6000 rpm or lower.  The 2" cutter head I refered to is 2" high and 4" in diameter without knives in it.  With some moldings the overall diameter can be as much as 6".  If I try to run a 6" diameter cutter on a 1 1/4 spindle at 7000 rpm I get a lot of chatter.  Sometimes I need to run a 4" casing but at 7000 rpm my shaper sounds like its going to take off.  So I really think I need the slower speeds for some situations.

3. 
   Tao | Mar 29, 2004 02:17am | #16

   By chatter do you mean vibration when you are not cutting, or do you mean chatter on the wood?

   If it's vibration when you are not cutting, either your knives are not balanced or you have a brearing problem.  Either way, it would be much better for you to correct the problem rather than just slowing the speed down.

   If you are getting chatter on the wood, your wood is not supported firmly enough.  Most power feeders I've used don't support the wood well enough to make a 4" cut on the face of flat stock run on edge.    I used to make a back fence for those kinds of cuts and run the wood between the back fence and the spindle, like a sticker.  Obviously, you need a power feed for this.  I used it as a push feed, and used the outboard portion of the fence as a holddown.

   As I said before, I ran bevel edge (and lock edge) knives at 10000 RPM for over 20 years with never a hitch.  This includes taking some HEAVY cuts on an automatic shaper, and profiler, as well as hand fed template work and power fed straight work.  If your assembly is over  6" diameter, then slowing to 7000 would probably be in order, but if the machine and cutterhead are in good condition and properly installed, you don't have to slow down below the stock speeds of the machine.

   I would recommend that you find the real problem and correct it.  You'll be a lot safer.  I've run a couple of really old (flat belt) shapers with slow spindles, and believe me, it doesn't do much for the quality of cut.

   Michael R.

2. 
   lynnroy | Mar 25, 2004 09:26pm | #4

   Is it dangerous to replace old motors with new motors with more horse power but the same rpm range?

   I have just bought an ancient shaper that is supose to be very stout. I purchased it site unseen.

   I like excitement and I have found that if the guy is of a certain age and a long time wood worker he is most often honest.

1. 
   JohnWW | Mar 25, 2004 11:19pm | #5

   Lynn,

   A tricky question without seeing the machine in question, but in general as long as the motor mounts properly you can, within reason, go to a greater horsepower.  I wouldn't go to anything larger than what is normally supplied on a machine of equivalent size.  For electrical safety you may also have to replace the motor's controls at the same time, since it will need to have a magnetic switch matched to the new motor's horsepower.   

   Another warning on increasing the power is that you shouldn't abuse the machine by overloading it just because the new motor can handle it, some of the other components may not be up to the added strain, especially if the machine is very old. 

   The risk with an old shaper is that the spindle could shear off if it had past damage or fatigue cracks, but if those problems exist the spindle might eventually give out even with the existing motor.  If you wanted to be safe, pull out the spindle and take it to an automotive machine shop and have them test it for hidden cracks.  If the shaft is visibly chewed up, except for the usual wrench dings on the cutter end, it should be retired. 

   On a lathe, not having too much horsepower is something of a safety factor, but on most woodworking machinery all it takes is a fraction of a horsepower to do damage to the human body, so whether a machine had three or five horsepower at the time of an accident is usually not terribly relevant.

   The bigger risk on many older machines is that they often lacked even the most elementary of guards and often had cutter heads that could do incredible damage if you got tangled up in them.  Some old machines are beautiful, but too dangerous to use without a fair amount of modification which often isn't practical or feasible.

   Have fun but Be Careful, John W.

   P.S.  Just so there is no misunderstanding:

   All of my comments here apply only changing the machines motor for one of greater horsepower, without changing the cutter head RPM.  There are very real risks associated with INCREASING THE CUTTER HEAD'S SPEED beyond the machine's or the cutter head maker's allowable maximums and this SHOULD NEVER BE ATTEMPTED.

    

    

   Edited 3/25/2004 4:38 pm ET by JohnW

   Edited 3/26/2004 11:41 am ET by JohnW

   Edited 3/26/2004 11:43 am ET by JohnW

2. 
   GHR | Mar 26, 2004 04:59pm | #7

   It is always dangerous to replace a small motor (low hp) with a larger motor.

1. 
   JohnWW | Mar 26, 2004 06:27pm | #8

   George,

   Claiming that increasing motor size is "always dangerous" seems a bit alarmist, could you explain why?  If we are talking about a modern machine fitted with the largest motor installed by the manufacturer, I would question the wisdom of increasing the motor's size, but that wasn't the case in the question being asked. 

   Increasing motor speed or changing pulley sizes to increases cutter speed will create a dangerous situation but again, as I'm reading the questions, this was not going to be attempted.  Just to be sure, I will go back and edit my posting to make the risks of increasing speed very clear. 

   I think my reply covered the possible problems and risks of changing motors, but I've seen motors changed out often enough to know that it can be done safely.  Used machines regularly show up fitted with undersized motors for some unknown, long forgotten, reason and there is no risk from replacing the existing motor with a properly sized motor.

   John W.

   Edited 3/26/2004 11:45 am ET by JohnW

1. 
   GHR | Mar 28, 2004 02:16am | #11

   With a larger (more hp) motor larger loads are placed on all components. This leads to parts failures and damage to people.

2. 
   JohnWW | Mar 28, 2004 05:08pm | #12

   The loads placed on a machine's driveline are not determined by the size of a machines motor, the load or stress on the driveline is determined by the load on the cutter.  On smaller woodworking machinery, the design of the cutters and the limits on how fast an operator can hand feed stock will keep the load on the driveline within a safe range no matter what the motor's size. 

   For example, you could install a 1/4 hp motor on a tablesaw and it would spin the blade just fine, as long as you didn't try to saw any wood with it.  To saw wood you need to install a 2 hp motor on the saw.  With that motor and a sharp blade you could now rip a 2" thick board at a good pace. 

   If you increased the motor size to 4 hp you might rip the stock a little faster, but there is a limit to how fast you can hand feed stock and be in control.  Working by hand, you simply wouldn't be able to feed the wood twice as fast as you did on the 2 hp saw. 

   If you went up to a 10 hp motor you still wouldn't feed the stock any faster than you did with the 4 hp motor and, as a result, the stress on the machine would be the same as when using a 4 hp motor.  Of course there is no point to installing a 10 hp motor, the extra money spent wouldn't improve the way the saw cut, but the motor wouldn't be placing any additional stress on the saw's driveline.

   As long as the machines operator is rational, and uses only cutters made for the machine, it is nearly impossible to overload a woodworking machine's driveline when hand feeding stock no matter what the motor size.  In 35 years of woodworking I have never seen a driveline failure on a hand fed home shop or light industrial machine, I just don't think it is possible.

   John W.

3. 
   GHR | Mar 28, 2004 05:36pm | #13

   If you used small text, I would not feel you were shouting at me.

   You don't see the failures because few people install larger motors than a machine is designed for.

   In addition, if as you say one cannot effectively use the power of a larger motor, the larger motor is economicly unsuitable.

4. 
   JohnWW | Mar 28, 2004 06:25pm | #14

   I'm not using large type to "shout", but I apologize for offending you. 

   I find it very fatiguing to try to read small type on a computer screen.  I sometimes work for long stretches at a computer, I'm a writer in addition to being a woodworker and machinist, and I just don't see the point to getting eye strain.  I'm only going from size 10 to 12 and I don't have some fantasy that putting my ideas in large type is going to make them more valid, it is just making them easier to read. 

   You are right that it is uncommon to see oversized motors in woodworking machinery but I have seen some and they did not have problems. 

   In any case, my primary point was that the cutters, and limits on how fast stock can be hand fed, keep the load on a machine within safe limits no matter what size the motor is and that is generally safe, within reason, to use a larger motor if one is available.

   In one of my postings I said that there was no point in using a larger motor than was usually installed new in a machine of similar size and in my last post I said that installing a larger motor than was needed was a waste of money, so I have already agreed with you on your last point.

   John W.

2. 
   Tao | Mar 26, 2004 01:59am | #6

   Dave, are you sure about those RPM limitations?  I ran 2" wide bevel edge knives at 10,000 RPM for years on hand and automatic shapers, with never a bit of trouble.  Surely a corrugated back knife is more secure that bevel edge?

   I'm not encouraging you to do anything unsafe, but it might not hurt to double check.  10,000 and 7,000 or thereabouts has been a standard for an awfully long time, and it takes a pretty large diameter cutter to require a lower speed.  No sense changing things around if it's really not necessary.

   Is it your spindle size that is a problem?  3/4" spindles can get pretty scary with heavy cutters.  1 1/4" or even one inch is a lot better.  Most deltas have interchangeable spindle sizes, and that's a lot less trouble than changing your drive.  Cutters are not too expensive to bore out.

   Michael R.

   
   

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   Edited 3/25/2004 7:04 pm ET by Woodwiz

3. 
   jako17 | Mar 29, 2004 04:24am | #17

   Dave reading some of your posts,ie stalling a 5hp motor etc IMHO I would be looking at your technique closely.Things you might look at are feed rate ,depth of cut,how high on the spindle is the head, spend out on 4 knives rather than 2 on the serrated head,insufficient support for the stock,I set the knives with a clock gauge both for height and concentricity(I have had knives ground indexed to different serrations)If some of these points have been raised by other posts please excuse the repetition.Since I escaped being disembowelled by a serrated backed knife that shattered and exited by the dust boot rather than my abdomen the thought of stalling 5 hp boggles the mind.

4. 
   dwf67 | Dec 17, 2011 12:55pm | #18

   Shaper speeds

   I have a 3hp Delta/Rockwell shaper and I am running a 7" pulley on the motor(the one that came on it years ago). I have a step pulley on it and it is on the smaller size. I want to put it on the larger size on the spindle but how do I do that and also if I put it on the larger size of the spindle will it slow it down or speed it up? Anyone that can help email me @ [email protected]

   I have never had to mess with the speeds on the bits I have ran in the past but I am changing over to inset bits and I am getting chatter on the raise panels. I have had the spindle and bearings checked and everything is like new. Any help would be very much appreciated.

   Thank you,

   David

1. 
   JerryPacMan | Dec 18, 2011 10:09am | #19

   Below is a link to calculating pulley diameters and speeds.  Don't forget to click the circle that you are solving for.  I find that the Freud 4 wing raised panel cutters work good.

    http://www.culvermotor.com/Engineering-Formulas/Pulley-and-RPM-Calculator.html