View Full Version : noob grinder question


thompsje
03-18-2003, 05:49 PM
Hi everybody,

First, even though everybody else has said it, this is an awesome forum. I'm still digesting a lot of information and completely in awe of some of the creations posted here. It has really inspired me to get back to something that I love to do. (Spent the last 5 years as an apartment dweller with no power tools). But now I have a house, some space, a tax return, and a very loving wife who seems willing to indulge me in my knifemaking pursuits.

With that in mind, I am looking at getting a belt grinder. I have read the FAQ about the KMG1 and have seen the Baders in the Texas Knifemakers catalog. My question isn't so much which one to get, but what do I need in terms of attachments?

Can the KMG1 Rotary Platen suffice to do some of the slack belt type of shaping that I imagine doing for handles/scales, or would I need the actual attachment for that? Can I grind edges against the rotary platen setup, or would I need a more "normal" platen? Do I need a contact wheel if I don't plan to hollow grind? Should I worry about AC/DC conversion speed control, pulleys, or just get a Variac?

As you can see, I'm full of questions. I have used belt grinders before (in a machine shop summer job many, many moons ago), but never one configured just for knife making. Everything else I have ever done has been by hand.

Thanks in advance for any advice/input,
-Jeff

edit: mispelled the subject I was so excited. :)

Ray Rogers
03-18-2003, 06:39 PM
Somebody who owns a KMG will probably come along soon and answer those questions for you or you could talk to Rob Frink at Beaumont (the people who make the grinder) and get it straight from the horse's mouth.

But, I wanted to throw in my 2 cents on variable speed and contact wheels. My main grinder is variable speed and I can't imagine life without that feature. The more horsepower you can get, the better, with a variable DC motor. If you decide to go with the pulleys, that's good too but the DC units are a lot more convenient.

A variac steals a lot of power from the motor to slow it down. The only affordable variacs I know of are the router control units and they don't work on more than 1 hp if I recall correctly. There will probably be a lot of opinions on this and that is mine.

Yes, you'll probably want a contact wheel. They get used for a lot of things besides hollow grinding. They are very handy when shaping a folder handle or a fixed blade handle, rounding corners and edges, putting curves in blades (like a clip area or recurve), etc. You could probably learn to do many of those things on a platen but I don't think most guys do it that way. Maybe that KMG rotary platen is an exception though...

whv
03-18-2003, 07:43 PM
first, welcome to ckd.
i can't answer your question directly, but here is ed caffrey's review (http://www.caffreyknives.net/KMGarticle.html) which is out on his web site. nice machine!

Darren Ellis
03-18-2003, 10:07 PM
Hi Jeff,

If I were you I'd get a KMG1 set-up with a flat platen and a contact wheel size of your choosing...the 14" wheel is sure nice though. The beauty of the KMG1 is the versatility it provides, you can always get more attachments later on with a tooling arm so you can just slide one out and slide the other back in. Give Rob Frink a call or email him, he's a super nice guy and is extremely helpful. Variable speed is a must have feature in my opinion. I have a fixed speed Grizzly and recently got a KMG1 which I am setting up and really wish I had listened to everyone who told me in the beginning to save my money and just buy a variable speed KMG1 from the beginning. Rob put a lot of research and development into this grinder, going as far as to perform computer simulations on the model to tweak different variables in the design to optimize everything, as I understand it. On top of that, his craftsmanship is superb. Hopefully someone with a rotary platen will chime in and give a review of it, I'm interested in hearing about it as well! :)

-Darren

mmattoon
03-18-2003, 11:30 PM
Howdy. I'm just another FNG myself. I'm also looking at getting a KMG down the line (When I get my taxes done!) I did a bit of searching in the archives, and it seems that variable speed is worthwhile, despite added expense. People that commented regarding variable speed, regardless of brand of grinder, typically closed by saying they wouldn't live without it. Consider AC variable speed. Search the archives for "VFD". Stands for Variable Frequency Drive. This is cool stuff. You can run a 3 phase motor at variable speed with single phase 220-230 input. Setting up the controller IS technically difficult, but not impossible. My other finding was that general consensus was 1.5 HP as minimum. I found a 2HP motor/VFD combo for 385.00/421.00 delivered to my door at www.dealerselectric.com. That's about 180.00 cheaper than I could find locally. I'm also lucky enough to have a friend that's an industrial electrician. I understand about half of the manual! It's the other half that scares me:) As far as the contact wheel setup, it's cheaper if bought up front. The feedback I got was that even if I didn't do hollow grinds, the contact wheel was useful for profiling, (grinding the outlines), and for shaping handles. I have not got any good handle on the use of the rotary platen attachment. It seems that belt wear is reduced by the support provided by the backing belt, as opposed to a steel platen backing. I will probably get one. I can see many non knife making uses it would be good for that make it worthwhile for me to try. For what it's worth. Regards, Mark

Darren Ellis
03-18-2003, 11:36 PM
Hi Mark,

I have that very combination VFD three phase motor you mentioned and should have it up and operational this week. Hopefully by the weekend I'll be able to report on my initial impressions. The beauty of the VFD drive is constant torque. I have a 1 H.P. set-up on the way also with a 56HC frame to hook up to the horizontal grinder Rob just released. :)

-Darren

mmattoon
03-19-2003, 12:49 AM
Darren, would you consider sending me your programing parameters? I understand the programing process, just not how to optimize the parameters for the motor. Some of the pre-programed parameters seem appropriate, while others seem questionable to me, who knows little. Are you going to leave the VFD exposed? I sand a lot of wood and stone in my shop/garage, and am trying to come up with a plan to keep the VFD clean, and fed with plenty of fresh air. The plan so far is to raid old computer parts for a couple 120mm fans, filters, power supply to run them, build an enclosure to house and filter airflow, and extend the analog style pontentimeter knob. Put in a small window for the LED display, and the VFD should be able to survive in my garage. I'm a little Cro-Magnon in my work habits, hence the worry about protecting the VFD. Let me know how the unit works for you. I'm probably a month or so away from buying the KMG, and trying to set it all up. Regards, Mark

Darren Ellis
03-19-2003, 01:21 AM
Hi Mark,

Send me an email so I have your return address. When I get them worked out, I can send you an email with what I came up with. I've been so busy with helping with the construction of a hydraulic press to bring to Batson's and the last of the flood cleanup we experienced a few weeks ago that I haven't set down and spent some quality time with the manual yet.


"I'm a little Cro-Magnon in my work habits, hence the worry about protecting the VFD" :)


All I'm planning to do is something I saw Gary Riner do in his shop for a temporary paint booth. I've run small steel cable from one wall near the ceiling to the end of my grinding/buffing area and then made a 90 turn and went to the wall to partition off this space. I'm hanging clear plastic sheeting with chain attached to the bottom (for weight) on this cable and will create a little room to hopefully keep the grinding dust contained and the wood dust from the wife's woodworking area out of my part of the shop. Later I plan to add an air cleaner overhead exhausting out of the "little room" and possibly a box fan with a filter blowing in. Dust collection for the grinders is via a 2 h.p. HF dust collector connected to one of those pseudo cyclones attached to a metal garbage can. I think this will probably be good enough, along with cleaning it with the shop vac from time to time. Most of these controllers are fairly robust. If you've ever been into a production factory you'd be really surprised that things keep running for so long under some pretty extreme conditions. Before I went back to school I worked as an industrial electronics technician (which just means I did some electronics and a little of everything else required to keep production machinery running) in both a printing plant and a brass and aluminum forging and machining plant. It amazed me that those places actually kept running and the equipment wasn't broken down all of the time given the conditions present and the managements aversion to preventative maintenance! Sounds like your VFD will have a big smile on its face. :)

-Darren

mmattoon
03-19-2003, 01:41 AM
"Dust collection?, We don't need no stinkinking dust collection!" Sorry, couldn't resist. E-mail = mmattoon1@earthlink.net Last year I had the bright idea of cutting some pipestone in the porch off the kitchen with a 10" tile saw. The water circulation system was intermittent at best. Turned about half my house red. Sometimes it's good to be single........

Osprey Guy
03-19-2003, 03:22 AM
I think you'll find this thread pretty much covers it...
http://www.ckdforums.com/showthread.php?s=&threadid=8931&highlight=KMG+AND+maska

Among other things regarding the KMG, that thread addreses the subject of HP at length.

As you'll discover when reading that thread, I have a 1HP Leeson...and months later I couldn't be happier. I have a friend with a 1.5 HP "Cheapie" AC motor and we both feel my 1HP yields more power than his 1.5HP...Like anything else, there's horsepower and then there's horsepower

Just to qualify myself, I haven't put enough grinding practice in yet to suit many of the folks here,...(Some seem to be in a bigger hurry for me to be grinding my own, than me...I'm taking my good old time while having a blast making my heavily embellished kit knives...) Having said all that, I still get plenty of use out of my KMG already...

You can't go wrong with the KMG...and as you'll read you probably won't require a whole lot of horses...

Note: Now that I'm back at work and making a full-time income, my agenda has changed, and I expect to be picking up the pace on my grinding (less pressure now to be making and selling expensive kit knives;) )

Good luck...have fun the new grinder!

Dennis Greenbaum

Yeah Baby!:smokin

PS. I'm still trying to get used to being back on a work schedule...I fell asleep way too early and woke up at 3:30am...couldn't get back to sleep, so here I am:rolleyes: :p

floridafred
03-19-2003, 06:44 AM
I just wanted to add my own satisfaction with the KMG. After using it for a few months I find it to be a great machine. I purchased mine with the three speed pulley system which does a fine job for me. I have the 8 inch contact wheel, platen and recently purchased the small wheel attachment which is great for getting into the small inside curves prevelant in many of my profiles. I've tried profiling on the platen and the contact wheel and find the contact wheel to be much more efficient for profiling. If I were to do anything different I would probably get a little larger contact wheel. Eventually I may opt for the rotary platen but at this point I can pretty much do anything I want to do with the attachments I have.
A couple of things I would suggest is a good air filtration system. I already had one since my shop is an existing wood shop. After the first day of grinding I could not believe how black the filters got in my system. This made a beleiver out of me.
The second thing is use good belts. I've used cheap belts and good 3M belts. Good belts are a no brainer.
One last suggestion: When moving the belt by hand to be sure it is properly lined up on the wheels be sure to let go of the belt before your finger goes between the belt and contact wheel because this hurts like hell. Use it safely and wisely.:smokin

Rob Frink
03-19-2003, 06:43 PM
Hello Jeff,

I'll try to answer a few of your questions....

The rotary platen can be used for slack belt work however I think it is a bit too stiff for handle shaping and I prefer to use a standard slack belt set-up which allows the belt to conform to more generous contours on the handle. I particular, I like to split a belt to about 3/4" or 1" wide for handle shaping. Just my preference...

Your best results for flat ground blades is to use the traditional platen attachment to rough out your flat grinds. The rotary platen will save hours when it comes to finishing flat ground blades by reducing the amount of hand sanding/stoning. Speedy finishing with fantastic results is where the Rotary Platen really shines. As far as rough grinding with it.....not the best choice unless your making veggy choppers and clevers.


Yes, you need a contact wheel. You'll find a bazillion uses for it other than hollow grinding. It is much more efficient for hogging out profiles compared to the platen. It also produces very nice edge finishes such as on the spine and around the handle on a full tang knife. It can be used for handle shaping as well....and who knows what else. The most popular size is the 8". They out-sell all the other sizes about 10:1.

For speed control.....you have a ton of options. You can run a KMG with just about anything that'll spin it. The most popular choice is a 1.5-2hp motor....or even bigger. If you have 220V in your shop then you can use standard AC, DC or a VFD. If you only have 110V, then I say you are limited to a 1.5HP standard AC motor and do not recommend a DC set-up on 110V. Multiple grinding speeds is a neccesity. You can get it by using a variable speed motor, or by using a single speed motor with a selectable set of pulleys. Either way, they both generate the same speeds. i.e...2000 ft/min is 2000ft/min.... regardless of how you get it. The VS set-ups are very convienient and also more expensive. The step pulley set-up is much less $ but requires you to stop to change the speed. Home shop drill presses typically have step pulleys for speed selection....I haven't seen too many drill presses with VS motors and drives. More food for thought...


If you need a recommendation: I suggest the KMG8 package, a small wheel attachment with a few wheels, and the 1.5 hp AC motor with a set of step pulleys. You can run this on 110V or 220V and it will make a ton of knives. As you learn more about how you make your knives...and what type of knives you like to make....you may buy more attachments as needed.


These are just some of my thoughts and opinions. There are many ways to do the same thing so simply consider what I've said and be sure to listen to others....then decide. There are several very nice grinders on the market as well...so you have plenty of decisions to make. The most important decision is to get started. Once you start making knives...then the more you'll understand what you need.

I hope this is helpful.


Sincerely,
Rob

floridafred
03-19-2003, 07:06 PM
I'm glad to see that Rob jumped in here and I fully expected he would. Just to reiterate it is one hell of a machine and it's really nice to have Rob behind it. What he said is pretty much what I have so I can confirm that it is the best way to go. At least I am very happy. I profiled 12 blades today and didn't break a sweat.

Hey Rob: That small wheel attachment is right on the money. Took your advice on setting up, in particular the 3/4 inch wheel. No problem. It does just what I wanted. I'll be in touch.

thompsje
03-20-2003, 03:23 PM
Thanks very much for the input guys. Hopefully this weekend I'll get myself out to Home Depot and get enough lumber to build some decent work benches. After that, I'd guess that a KMG1 won't be too far behind.

Thanks again,
-jeff

yendor
05-15-2003, 10:36 PM
for years i have used a 1/2 hp sears crap 1 x 42 grinder. Today i just got a kmg-1 with all most all the attachments you can get. Wow i Belive any other grinder is a waist of money.

floridafred
05-16-2003, 06:48 AM
As time goes on you will learn to appreciate it even more.