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Thread: 3HP not enough?

  1. #1
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    Default 3HP not enough?

    Looking at buying/upgrading to a 20" Carbatec thicknesser with a single phase 3HP motor, I currently have a 12" 1800w(~2.5HP) JET benchtop thicknesser, and this struggled with a 9" wide slab of yellowbox, even with new blades(HSS).
    I was thinking this was a decent upgrade, but now comparing the power of these motors, I'm not sure it is.

    If I did the helical cutterhead upgrade on this 20" thicknesser, how much easier does it cut?

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  3. #2
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    I agree with your comments re HP. Check out the Grizzly USA website for a comparison where you will see they have 220V 5Hp single phase motors on their 20 inch thicknessers. In my own case I did replace a 3Hp SP motor with a 5Hp SP motor on my 15" Carbatec thicknesser as it was underpowered especially when fitted with the Byrd cutter head. Whilst that was quite a job to fit with new mounting and wiring/switchgear along with a new power circuit it made a very positive difference with difficult hardwoods. In regard to easier cutting I have observed that the major issue is users want to take off too much in one pass and this can easily overload 3Hp motors. I have also recall being shown some data from Felder showing power demands from different cutter heads relative to their own machines. In past years 5Hp models were also sold in the USA on 15" machines for heavy duty use. My wood group has a new Powermatic 20" thicknesser with a 5Hp (3.7Kw) 3Phase motor and Byrd cutter head and it seems to handle large slabs without issues.
    Cheers,
    Paintman

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    How much were you trying to take in a pass? Yellowbox is tough stuff, so I'm not surprised you struggled with a benchtop unit.

    IMO, 3hp is nowhere near enough for 20", especially with the feed on the same motor. We have 10hp on 24" helical head at work with a separate 1hp feed motor and that might push through a 2mm full width pass on the slowest feed; 3hp on 20"...maybe 0.5mm a pass?

    Interesting side-note on power requirements for helical heads, they may actually take more power than straight knives in some cases. We went from a 4-knife straight head to a 10-row helical and it certainly sounds like it's working harder. I didn't have the foresight, equipment or skills to take before/after measurements, maybe someone with more knowledge can help?

  5. #4
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    Quote Originally Posted by elanjacobs View Post
    How much were you trying to take in a pass? Yellowbox is tough stuff, so I'm not surprised you struggled with a benchtop unit.

    IMO, 3hp is nowhere near enough for 20", especially with the feed on the same motor. We have 10hp on 24" helical head at work with a separate 1hp feed motor and that might push through a 2mm full width pass on the slowest feed; 3hp on 20"...maybe 0.5mm a pass?

    Interesting side-note on power requirements for helical heads, they may actually take more power than straight knives in some cases. We went from a 4-knife straight head to a 10-row helical and it certainly sounds like it's working harder. I didn't have the foresight, equipment or skills to take before/after measurements, maybe someone with more knowledge can help?
    How much was I trying to take off? The absolute bare minimum, maybe 1/8-1/4 of a turn of the wheel.

    I agree yellowbox is tough, its nearly the same hardness as ebony!(Janka 2.9k vs 3k)

    Cheers for the insight, if I need to upgrade the motor as well as the cutterhead, I don't think I'll be purchasing this one.

  6. #5
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    Quote Originally Posted by PaintMan View Post
    I agree with your comments re HP. Check out the Grizzly USA website for a comparison where you will see they have 220V 5Hp single phase motors on their 20 inch thicknessers. In my own case I did replace a 3Hp SP motor with a 5Hp SP motor on my 15" Carbatec thicknesser as it was underpowered especially when fitted with the Byrd cutter head. Whilst that was quite a job to fit with new mounting and wiring/switchgear along with a new power circuit it made a very positive difference with difficult hardwoods. In regard to easier cutting I have observed that the major issue is users want to take off too much in one pass and this can easily overload 3Hp motors. I have also recall being shown some data from Felder showing power demands from different cutter heads relative to their own machines. In past years 5Hp models were also sold in the USA on 15" machines for heavy duty use. My wood group has a new Powermatic 20" thicknesser with a 5Hp (3.7Kw) 3Phase motor and Byrd cutter head and it seems to handle large slabs without issues.
    Cheers,
    Paintman
    I'm very patient, if I could take off .25mm per pass I would, but it really bogs down, and I need to help it through by pushing/pulling.
    Would a 5HP(3.7kw) trip a standard 15amp circuit breaker? 230v * 15amps = 3450w, I think starting up the motor would trip this breaker, 4hp might be my limit unless I get some electrical work done.

  7. #6
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    I think breakers have a tolerance for higher inrush current

    How much is the machine you're looking at buying? You might be able to find a decent used one and put the savings towards a helical head

  8. #7
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    Quote Originally Posted by elanjacobs View Post
    I think breakers have a tolerance for higher inrush current

    How much is the machine you're looking at buying? You might be able to find a decent used one and put the savings towards a helical head
    The one I'm looking at is used and $2k, these 20" 3HP ones retail for ~$2.9k.
    I'll ask some of my electrical minded friends about inrush current, see what they say.

    Thanks.

  9. #8
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    It is my personal opinion that most carbatec machines are not built for heavy duty work. 20" I'd want 5hp just look at the HP felder supply with their machines. Even those that are 12-16".

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    Quote Originally Posted by hurcorh View Post
    It is my personal opinion that most carbatec machines are not built for heavy duty work. 20" I'd want 5hp just look at the HP felder supply with their machines. Even those that are 12-16".
    Yep, I'm coming to the same conclusion.

  11. #10
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    Quote Originally Posted by elanjacobs View Post
    I think breakers have a tolerance for higher inrush current

    How much is the machine you're looking at buying? You might be able to find a decent used one and put the savings towards a helical head
    Also was told by an electrician you can swap out a 15amp breaker for a 20amp breaker on your switchboard to solve the inrush current problem.
    2.5 twin active is rated to up to 20amps, you can also buy power points that are 20amp rated, that have bigger prong hole things, so 5hp single phase is doable.

  12. #11
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    bk201

    There are a few issues you have raised and I have had a little to do with some of them.

    Firstly, a bit like muscle cars (there's no substitute for cubes), there is no substitute for horsepower. If I said you should go for the largest HP version possible, that may not be absolutely neccessary, but you should be mindful that all machines have their limitations. I'll give you an example. A while back I was attempting to thickness some 150mm Stringybark planks for a friend to make a BBQ table. At the time I was using my 300mm Timbecon "lunchbox" thicknesser. I quickly realised it was going to be an all day job taking a "skim" off each time and the two of us carted the timber to another friend, who had an industrial style 24" thicknesser. The 24" machine took three planks at a time and took off 3mm at one hit without even blinking.

    So a lot depends on what you plan on doing with your machine. I have one of Carbatec's 20" thicknessers with the 3HP single phase motor. This should run off a 15amp outlet, but because I have a 20amp outlet I have connected it to that. Incidentally you can have 32amp single phase power point also which in theory will allow you up to 7.5KW (10HP), but as with the 20amp you can't just substitute the plug. The wiring normally has to be up graded and the wire gauge will increase as the the distance extends. You best bet, as in cheapest option, is if your power point is right next to the switchboard, but you need to consult with your electrician on requirements for your situation.

    A thicknesser is started unloaded (without timber in the cutter head) so normally the startup current (inrush current) is not an issue. If you try to take too large a cut in a wide board the machine may bog down under the load and that is the circumstance when it may trip your breaker. The solution is to take a lighter cut.

    Generally I have been pleased with my machine. Many of the timbers I use are difficult like your Yellowbox: Ironbark, Grey Gum, Forest Red Gum and Tallowwood are some. I rarely take off more than 1mm at a time and this may be on a board that is 150mm to 200mm wide. I have ended up with three sets of blades, which I sharpen myself on an old fashioned, but dedicated machine. Blade sharpness is quite important with the harder, hard woods and very noticeable in the ease of planning.

    Remember you can consider a three phase machine (5HP) if you are prepared to use a VFD and have the wiring and plug to suit, but that may not be an immediate option as you are looking at second hand machines. The only issue I have really had with my thicknesser is that the feed rollers seem to gum up and I have to clean out the timber residue as they become reluctant to feed the timber through the machine. However this is partly to do with putting some semi dried timber through on occasions.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

  13. #12
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    Quote Originally Posted by Bushmiller View Post
    bk201

    There are a few issues you have raised and I have had a little to do with some of them.

    Firstly, a bit like muscle cars (there's no substitute for cubes), there is no substitute for horsepower. If I said you should go for the largest HP version possible, that may not be absolutely neccessary, but you should be mindful that all machines have their limitations. I'll give you an example. A while back I was attempting to thickness some 150mm Stringybark planks for a friend to make a BBQ table. At the time I was using my 300mm Timbecon "lunchbox" thicknesser. I quickly realised it was going to be an all day job taking a "skim" off each time and the two of us carted the timber to another friend, who had an industrial style 24" thicknesser. The 24" machine took three planks at a time and took off 3mm at one hit without even blinking.

    So a lot depends on what you plan on doing with your machine. I have one of Carbatec's 20" thicknessers with the 3HP single phase motor. This should run off a 15amp outlet, but because I have a 20amp outlet I have connected it to that. Incidentally you can have 32amp single phase power point also which in theory will allow you up to 7.5KW (10HP), but as with the 20amp you can't just substitute the plug. The wiring normally has to be up graded and the wire gauge will increase as the the distance extends. You best bet, as in cheapest option, is if your power point is right next to the switchboard, but you need to consult with your electrician on requirements for your situation.

    A thicknesser is started unloaded (without timber in the cutter head) so normally the startup current (inrush current) is not an issue. If you try to take too large a cut in a wide board the machine may bog down under the load and that is the circumstance when it may trip your breaker. The solution is to take a lighter cut.

    Generally I have been pleased with my machine. Many of the timbers I use are difficult like your Yellowbox: Ironbark, Grey Gum, Forest Red Gum and Tallowwood are some. I rarely take off more than 1mm at a time and this may be on a board that is 150mm to 200mm wide. I have ended up with three sets of blades, which I sharpen myself on an old fashioned, but dedicated machine. Blade sharpness is quite important with the harder, hard woods and very noticeable in the ease of planning.

    Remember you can consider a three phase machine (5HP) if you are prepared to use a VFD and have the wiring and plug to suit, but that may not be an immediate option as you are looking at second hand machines. The only issue I have really had with my thicknesser is that the feed rollers seem to gum up and I have to clean out the timber residue as they become reluctant to feed the timber through the machine. However this is partly to do with putting some semi dried timber through on occasions.

    Regards
    Paul

    Thanks for the detailed reply!

    This is more future proofing, I don't want to buy this 3hp, then in a few years it struggles with some slab I'm cleaning up, so I'm trying to buy one that will last my lifetime.
    So if a motor is a 5hp motor, and it bogs down trying to cut a wide slab, can it draw more than 5hp?
    3 phase is a possibility if the right machine came up for sale, I got a quote to get it connected to my switchboard from my energy supplier: $800. I'm looking 2nd hand as I can't justify spending money for brand new tools, when I know there are machines out there that are up to 100 years old that will still do the job, that and I like finding a bargain

  14. #13
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    The availability of three phase power completely changes the ball park. $800 sounds like a good deal. I would go for it. This now extends your scope of second hand machines in particular. The 3Ph machines are often quite cheap because not everybody can use them. You can also consider the ancient behemoths that were just magnificent but today are outmoded for commercial use. Thicknessers and Jointers fall into this category but other wood working machines too.

    Regards
    Paul
    Bushmiller;

    "Power tends to corrupt. Absolute power corrupts, absolutely!"

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