Jump to content
I Forge Iron

Newbie looking to buy my first Real Grinder


Recommended Posts

Hello all. I am looking for a 2x72 beltgrinder. My budget is @ $800-$900. I am looking at the OBM single speed setup. What thoughts do you all have for this machine? Do you have any alternative machines I should look at?

What belt recommendations do you have?

Thank you for any advice. I have learned much from this site and I am thankful for you all taking your time to share!

Link to post
Share on other sites

I ended up with the Ameribrade and after reading and watching vids and making a wish list of features I completely blew my budget ! I have a package that I think will cover all my needs. I have on order the grinder with 2 hp VFD, 7in drive wheel, 10 round contact wheel and tooling arm, flat platen with tooling arm, small wheel holder with tooling arm, 2 small wheels, The new tilting hinge for horizontal grinding, and the stand with arm storage. Usually the only negatives that I hear about the Ameribrade is that it uses 2in arms instead of the 1.5. I do find that the accessories that they make to be reasonably priced so I don't think I will regret my choice. Now comes the long wait as the are about 4 weeks out before shipping.

Link to post
Share on other sites

Sounds like you got all the bells and whistles.  Hopefully you have had some experience working with a lesser machine so you can fully appreciate what you have purchased.  Now make sure you order the right belts...

Link to post
Share on other sites

Oh I don't know Latticino. New guy breaking into a field, shops around with a strict budget, blows it on lots of bells and whistles because they sound/look good in the advertisements. Sounds like one of the gang to me. Here's to the beginner learning to use the bells and whistles that actually MATTER so he can help the next batch of new guys make fresh mistakes. 

If we're nice we might get a real deal on it used. :ph34r:

What I'm saying in my usual wise buttock way is we've all bought fancier stuff than we need, still do sometimes. :unsure:

Frosty The Lucky.

Link to post
Share on other sites

No, in this case I think he got all the right stuff.  I've used and appreciated all the extras he has picked up my self, though I haven't found the 90 degree swivel to be quite as important as I expected it to be.  Wish I had a better arm storage system, the shelves I use are very haphazard.  I just meant that if he had used a lesser machine he would appreciate what he spent all this money on.  The VFD and 2 HP motor alone will be game changers, in my experience.

I made my first blades with hand sanding only, from a premanufacturered blank that I clayed and heat treated.  My first forged blades got shaped on an old 4 x 36" belt sander  with Alumininum Oxide belts then hand sanded to a 600 grit finish.  I really like my 2 x 72!

Link to post
Share on other sites

More power's good for sure. I guess I sort of went the other way and built one and not being a knife guy I haven't used it enough to know what to do with the few "options" I built in. I used my 2" x 48" belt grinder for 35 years sharpening and dressing blades. Always hated how the platen didn't extend past the motor so I was seriously limited in how long a knife I could sharpen. My 2" x 72", under powered and sort of . . . odd as it is, is a pure joy. 

May we see pics of your new grinder Dangerruss? Please? We LOVE pics you know.

Frosty The Lucky.

Link to post
Share on other sites

I'm wondering about that 7 inch drive wheel and the effect on power.  I run a 4 inch drive wheel and at moderate speeds I can bog the 2 hp motor down if I lean into it.  Hope he's running it on 220 or it will only be about 1.5 hp.  That would almost certainly be underpowered with a 7 inch drive wheel.  Either way I hope we get an assessment after a bit of use.

Link to post
Share on other sites

where did you get the silly idea that a 2hp motor is only 1.5hp if it is ran at 120v ? its the same wattage draw at what ever voltage its wired for, meaning the same power factor

Link to post
Share on other sites

Steve, I've heard the same thing about loss of power running at 120 V single phase vs 240 single phase, each using a VFD to convert to 208 3 phase  for the motor, in the past from equipment manufacturers.  Something to do with losses in the drive electronics from not having two hot legs already out of phase perhaps?  I don't know but am curious about your take on that.

Link to post
Share on other sites

A two Hp single phase motor is rated for two Horse Power PERIOD,  Horse Power is the amount of work a motor can do, no matter what the rated voltage or phase configuration if wired correctly.  VFDs are not 100% efficient (physics says that no conversion ever is)  so there is some loss using them, most normally run at 80% efficient.

a 3 phase motor runs at 60%  power if running on only two legs and if you are wired for 240 volts and only using 208v of course its lower horse power because its wired wrong, low voltage will naturally give lower horse power. except for bad windings that is the ONLY way it runs at less than rated power, 

I will bet my 36 years experience and Electrical Masters license on it. anyone telling different is wrong

Link to post
Share on other sites

Steve, wasn't questioning you, just trying to get your take.  Specifically I was talking about VFD that are used not only as speed controls, but also to convert either 240 single phase to 3 phase or 120 single phase to 3 phase to work with a 3 phase, RPM controlled motor.  The KBAC 27D VFD are a common example I believe.

Nothing about incorrectly selected or wired motors.  Thanks for confirming that with the conversion  efficiency numbers.  Do you know if the percentage is different between 120 and 240 single phase?  My guess is yes.

Link to post
Share on other sites

I just looked up their manual.  Per the manufacturer the internal converter limits the output at nominal 115 V input to 5.5 amps, or 1.5 HP.  At an input of nominal 208 to 230 single phase, this drive will put out 3 phase at 6.7 amps, or  2 HP.  This is for the ubiquitous KBAC 27D drive rated for a 2 HP motor.  Other drives may be different.  In fact I'm still battling with the programming of an Eaton drive I have on a different grinder that appears factory set for torque limiting...

Link to post
Share on other sites

Agreed, which is why I mentioned phase conversion specifically in my posts on this thread.  I'm not aware of any single phase motors that can be speed controlled by a variable frequency drive (but I could be wrong about that).  I've only seen 3 phase motors used that way, so you either would need native 3 phase or a converter.  Perhaps someday ECM motors will be more common, but I'm not that familiar with their characteristics.

Link to post
Share on other sites
  • 2 weeks later...

I used files first. Then upgraded to a 1X30 HF . I have used it for a while and feel I have reached it's limits. I know that I can't buy skill. I do hope that a better tool will allow my skills to grow. I think the grinder is the most used of all the power tools in knife building so I wanted to have one I would not outgrow. 

I went the 7in drive wheel per the manufactures recommendations and according to them the output of the motor with the VFG on 120 is 1.5 hp. Hopefully I wont have any issues but I could always swap out the 7in to a 4in . This wait is hard!  I hope it ships soon.

Next upgrade is an anvil! I have been using a HF ASO and it's edges and face are showing some dents. I want and think I can afford at a hundred pound anvil. I have looked for used but the prices are crazy around here for broken junk. I think that new is what I will end up doing. I am very appreciative of the forum for all the knowledge that you all share. Thank you!

Link to post
Share on other sites
On 4/17/2020 at 6:03 PM, Steve Sells said:

where did you get the silly idea that a 2hp motor is only 1.5hp if it is ran at 120v ?

Gee, I don't know.  Maybe the manufacturer of the equipment.  The claim isn't about just the motor alone.  It's the entire system.  This is something I've seen on many many sites of people who sell variable speed 2x72 belt grinders with 2hp motors.  Maybe they all have it wrong.  Maybe in theory one can get the full 2hp out of a 3 phase motor running on 110v, which in our country will require a converter.   What matters is how much power we actually get in use with a given configuration rather than the rating label on the side of the motor and a theoretical but unrealistic input imho.

Link to post
Share on other sites

its all in the details, they would never state a motor is loosing power if wired for lower voltages.  You just said its the system they are using, yet argue with what I said about a motor ratings. Someone said a motor Hp is lower if wired for lower voltage and that is false.

I already explained that the converter is not 100% if you bothered to read it.   I also explained that using a VFD does not supply the rated voltage to the motor so of course its not full power, power drops as the (voltage) speed control goes down I already explained that as well, I am wasting my time and not every one needs a converter.  You only need a converter if you dont have 3ph power to the building. many commercial places have it as 3ph is a standard industrial system.

I commented about the motor which many people get confused about and think they have to buy certain things to get full power and that is not true they just dont pay attention to the details.  I say again its its wired for 120 volts and supplied 120 volts it will have the same HP as if it ran on 240 and wired for that voltage.  I was trying to help clear up confusion

Link to post
Share on other sites
On 4/17/2020 at 5:32 PM, Buzzkill said:

Hope he's running it on 220 or it will only be about 1.5 hp.

That's what I said.  YOU interpreted that to mean the motor only, and then used your straw man argument. 

It's not our fragile egos here.  We're trying to make sure people have good information when making purchases.  It doesn't really matter WHY someone will only get 1.5 hp out of a 2 hp system if it's run on 110/120v.  What matters is that with the system being discussed here, that is the case.  When you contradict that with information that does not pertain to the item being discussed, you are providing a potentially false impression to someone else who may be considering the purchase.  That creates confusion rather than clearing it up.

In my mind "it" was referring to the grinder as a whole since we were discussing a specific grinder and not just a motor.  If I came across to you or others as referring to the motor only then I can see the potential confusion and your desire to explain this further.  I have no desire to continue nitpicking on this, and anyone who has read to this point should now be clear on both points of view.

Link to post
Share on other sites
  • 1 month later...

At long last the grinder is here!! I’m still waiting for the flat platen and stand. Thanks to Fed-x ineptitude it won’t be here till Monday.

 I only got to play with it for @ 90 minutes . I’m amazed by how much metal it will move and how much cooler the steel is! I have to work all weekend so I won’t be able to get back to it till later Monday or Tuesday.

 

735EE8C9-EEEF-4D1C-992C-6821AD9D9EAD.jpeg

7040F11B-FFD5-443B-A66D-156D1FE7A279.jpeg

Link to post
Share on other sites

Good Morning,

Don't blame the carrier pigeon! You received the important part. Rome was not built in a day!!

Welcome to IFORGEIRON.

A Blacksmith makes Tools, Tools do not make a Blacksmith.

Neil

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...