Author Topic: OBM Grinder  (Read 2969 times)

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Offline Sarge

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OBM Grinder
« on: November 05, 2016, 11:49:03 AM »
Here is a sneak peak of what arrived yesterday...





I've been using a Craftsman 2x42" grinder for about two years and it has been great! Can't beat it for $169 IMHO but I considered it a stepping stone when I bought it. I've been looking for a 7x72 for a while - read endless reviews, critiques, etc. I know a guy that has had one of these for a while and was able to get first hand info from him. That tipped the scales in favor of this one and I finally pulled the trigger.

It's an Oregon Blade Maker chassis with a flat platen assembly. Base price for this one is $495 but I added a drive wheel and tool rest. A 3/4 HP VFD motor is available from OBM for $545 but I ordered a 1.5 HP from a different source.

Don't have the motor yet ... don't even have a belt ...

I'll post my progress here on the set-up, etc. for those interested.
"The man with the knapsack is never lost." Horace Kephart

Offline wsdstan

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Re: OBM Grinder
« Reply #1 on: November 05, 2016, 01:06:34 PM »
Nice color
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Offline Sarge

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Re: OBM Grinder
« Reply #2 on: November 05, 2016, 02:51:15 PM »
"The man with the knapsack is never lost." Horace Kephart

Offline crashdive123

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Re: OBM Grinder
« Reply #3 on: November 05, 2016, 06:53:17 PM »
Excellent.  I'm not familiar with that particular grinder, but you will like using a 2 X 72.

Offline 1066vik

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Re: OBM Grinder
« Reply #4 on: November 05, 2016, 08:05:11 PM »
never heard of them - but that's a nice price!
thanks for the tip!

Offline PetrifiedWood

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Re: OBM Grinder
« Reply #5 on: November 05, 2016, 09:52:25 PM »
Looks bombproof! Congrats!


Offline Dano

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Re: OBM Grinder
« Reply #6 on: November 06, 2016, 09:26:07 AM »
Congrats Sarge, that's a great looking grinder!!  Looking forward to hearing how you like it

Offline upthecreek

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Re: OBM Grinder
« Reply #7 on: November 06, 2016, 05:57:13 PM »
Can't wait to see what you make with this machine. Enjoy!

Creek
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Offline Sarge

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Re: OBM Grinder
« Reply #8 on: November 08, 2016, 05:51:26 PM »
Thanks, guys. This wait is killing me. The motor and belts should arrive this week. I'm looking forward to firing it up.

I hope it is the real deal. The frame is 1/4" thick plate steel, the tool rest and D-plate for the platen assembly are 1/2" thick. The platen is A2 steel. The tooling arms are solid 1.5x1.5" aluminum. The drive wheel weighs about 5 lbs...

Sorry, didn't mean to sound like an info-mercial. I haven't even used the thing yet.

I'm embracing the bumble bee color scheme.

I post some pics & details when I start on the set-up.

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Offline Sarge

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Re: OBM Grinder
« Reply #9 on: November 14, 2016, 08:11:42 PM »
I've worked a bunch the last week or so and haven't had much knife time. The motor arrived and sat a few a days before I even opened the box. I worked on it a little last night and finished it up tonight. She runs great!


I put it on a tool stand. If that doesn't work out, I'll mount it elsewhere. I painted an ammo can black to serve as a spark and debris collector. I still need to mount it more permanently. I didn't look at the dimensions on that paddle switch when I ordered it. It's huge! When it came in, my wife asked if it was a foot pedal. Haha.


I looked at a ton o' motors and finally ordered this one from electricmotors.com. (It was $229 total) It came with a super simple wiring diagram; so simple I could wire it. I wired it for 110v. 


I took extra time to measure and re-measure before drilling holes in the tabletop to mount the motor and grinder. I got fairly close. Once I bolted them down, only had to tweek the drive wheel up and down the shaft until it was in line with the other wheels.

I guess I'll call it done unless I have to re-mount it or make some adjustment(s). I've got a couple days off now and can hardly wait to put it to work. I'll offer my thoughts on it as I use it and get more comfortable with it. If anyone wants more info or details, just let me know. I'm glad I was able to talk to someone with first-hand knowledge and experience with the machine before I bought one.
"The man with the knapsack is never lost." Horace Kephart

Offline PetrifiedWood

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Re: OBM Grinder
« Reply #10 on: November 14, 2016, 08:50:20 PM »
Looks fantastic! I hope you make many awesome knives on it.

Offline wsdstan

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Re: OBM Grinder
« Reply #11 on: November 14, 2016, 09:22:33 PM »
 :thumbsup:  That is a great grinder. 
A man who carries a cat by the tail learns  something he can learn in no other way. 
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Offline Spyder1958

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Re: OBM Grinder
« Reply #12 on: November 15, 2016, 04:19:41 PM »
lookin good Sarge.
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Offline Dano

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Re: OBM Grinder
« Reply #13 on: November 16, 2016, 03:35:14 PM »

Offline crashdive123

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Re: OBM Grinder
« Reply #14 on: November 16, 2016, 04:39:47 PM »
Looks great.  Be careful with that belt though.  That style is best suited for surface grinding.

Offline Sarge

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Re: OBM Grinder
« Reply #15 on: November 16, 2016, 08:02:05 PM »
Thanks, guys. And thanks for the warning, Crash.

I painted and bolted a piece of plywood to serve as a lower shelf to mount the ammo can debris collector. I bolted the lid down to the plywood and the can slides in/out of the lid. I think I'm finished now but still haven't really christened it yet. I raked leaves and cleaned out gutters yesterday ... worked overtime today ... maybe tomorrow.

"The man with the knapsack is never lost." Horace Kephart

Offline Sarge

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Re: OBM Grinder
« Reply #16 on: November 20, 2016, 08:21:46 AM »
I finally did a little grinding last night. I cleaned up some blades that had been rough ground, HT and tempered. Still getting familiar with it but I am really happy so far. I went from the 2x42 @ 3600 RPM to this 2x72 @ 1800 RPM. Might not remove metal as fast (only used #80 grit and higher), but it feels like I have more control. Tool rest and platen are rock solid. Also went from 1/3 HP to 1.5 HP, so it doesn't bog down.
"The man with the knapsack is never lost." Horace Kephart

Offline wolfy

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Re: OBM Grinder
« Reply #17 on: November 20, 2016, 09:45:40 AM »
So......around $730 for the basic grinder w/motor, but minus platen & tool rest, shipping, tool stand, ammo box, belts, etc.   Will you be giving us a 'bottom line,' real-world figure for the turnkey outfit when you get all the belts you need and are set up to finish the first knife on the new machine? :shrug:

I'm NOT being a smartass, Sarge......just trying to compare the total end price of this grinder (I'm envious, BTW) to going the 'build-your-own-from-parts' route.  My guess is that your well-researched route would be comparable to building your own......somewhere in the neighborhood of $1K, but without the hassle of cutting out, drilling & welding all of the parts for the 'build-your-own' unit.  ???

I'm really enjoying your thread, BTW.......but it's dangerous! :doh: :lol:
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Offline Sarge

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Re: OBM Grinder
« Reply #18 on: November 20, 2016, 02:05:15 PM »
Well, I'd hate to get a fella in trouble, wolfy.... >:D

$1K would be a reasonable expectation .

I started this topic in case anyone was in this same boat trying to decide on a grinder set-up. I tried to do my homework and it's hard to always compare apples to apples. I thought about building one - a friend said he'd help with welding - but pricing good quality wheels and other components adds up quickly. Plus, I thought about the hours to make it vs. how many knives I could make in those hours - maybe one or two, maybe 3 or 4 ... I don't know. The Coote grinder gets some good reviews but you can't swap out tool arms, contact wheels, small wheels, and so on. I came close to ordering a Coote. Then I talked to a guy that owns and loves the OMB. His input tipped the scales for me.

Here are my itemized cost:
$558.47 Grinder chassis, with platen assembly & shipping
 $24.95 Tool rest
 $43.75 Drive wheel (with shipping) - plastic wheel is cheaper but I opted for solid aluminum
$229.00 Motor (free shipping)
 $75.00 Mounting - Tool stand, 10AWG power cord, plywood, spray paint, nut & bolts
 $90.00 Belts from TruGrit (from #36 ceramic to #600 Trizact)
$1,022 TOTAL

I'd call this the turn-key, ready to make a knife cost. Some of this cost could be cut. I bought a new tool stand instead of mounting on an existing bench or table. I also bought a bag of nuts and bolts so they all would match ... because I'm like that. Haha. Of course, you could spend more or less on belts. I think I selected a good variety based on what I've used with the 2x42 grinder.   

I considered running 220v power, 3 phase motor & VFD but decided to stick with 110v. Might one day regret not going with a VFD but not yet. My single phase motor has a start and a run capacitor. It does not kick the circuit breaker, make the lights flicker, etc. It is quieter than the 2x42, might even be quieter than the 1x30.

That's all I can think to offer now....HIH
"The man with the knapsack is never lost." Horace Kephart

Offline crashdive123

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Re: OBM Grinder
« Reply #19 on: November 20, 2016, 03:21:36 PM »
You can change the speed of your grinder by changing the size of your drive wheel.  I prefer mine to run around 4500 feet per minute (you may prefer faster or slower).  Here's a formula to figure out how fast your belt is moving..... Diameter of your drive wheel X Pi (3.14) X motor RPM divided by 12.  This will give you the surface feet per minute.

Offline imnukensc

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Re: OBM Grinder
« Reply #20 on: November 20, 2016, 06:52:41 PM »
Very nice grinder set up, Sarge!   :thumbsup:
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Offline upthecreek

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Re: OBM Grinder
« Reply #21 on: November 20, 2016, 07:20:46 PM »
Looks to me like you coulda got a less machine for more $$. Your setup looks top notch to me. Your craftsmanship it great already, can't wait to see what comes from your new tool.

Creek
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Offline PetrifiedWood

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Re: OBM Grinder
« Reply #22 on: November 20, 2016, 10:28:08 PM »
Biggest issue I had with my Grizzly grinder was high belt speed. It really made you concentrate not to ruin the temper.

Offline Sarge

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Re: OBM Grinder
« Reply #23 on: November 22, 2016, 11:00:00 AM »
Yep, I've cooked a couple blade tips with the 2x42 - it runs 3600 rpm / 4400 sfpm (per the specs from Craftsman). If my math is correct, the new one runs 1800 rpm / 1884 sfpm. I mounted the motor slightly elevated over the table surface to allow for a larger diameter drive wheel so I should be able swap wheels to speed it up if I want.
"The man with the knapsack is never lost." Horace Kephart

Offline PetrifiedWood

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Re: OBM Grinder
« Reply #24 on: November 27, 2016, 09:52:20 PM »
I would love to have a water cooled belt grinder. It would seriously cut down on dust in the shop too.

Offline Sarge

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Re: OBM Grinder
« Reply #25 on: November 28, 2016, 10:29:39 AM »
I would love to have a water cooled belt grinder. It would seriously cut down on dust in the shop too.
That  would be cool!

 Hehe, see what I did there?
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Offline crashdive123

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Re: OBM Grinder
« Reply #26 on: November 28, 2016, 05:40:37 PM »
If I had that, my wife wouldn't give me the stink eye when I come into the house.....meaning ---- take a shower before you touch anything.

Offline Sarge

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Re: OBM Grinder
« Reply #27 on: November 28, 2016, 05:50:07 PM »
I know that look. LOL

A fresh sisal wheel will provoke the stink eye, too.
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Offline Sarge

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Re: OBM Grinder
« Reply #28 on: December 23, 2016, 07:32:04 AM »
I've logged some hours on the grinder now and I really, really like it. I wish I had bought it sooner.

I wanted a larger tool rest area to work with my new grinding jigs. I know...a jig is like training wheels but I'm not comfortable free handing yet.


Here is the tool rest I bought with the chassis.


Here is the 1/4" thick plate I added. It simply bolts to the tooling arm.


Made two grinding jigs out of 1/4" thick 4x4" angle aluminum - one for larger/wider blades and one for smaller/narrower blades. I drilled and threaded a hole on ones side and use the thumb screw to adjust the grind angle.


I put a pin in the other side to help hold the clamped blade in place. Excellent control - I can walk the grind line up toward the spine or walk the cutting edge in toward the center line. I've even cleaned up a few blanks I couldn't seem to get right with the old wooden 2x4 jig.


I've played with a dagger grind on this push dagger. Never tried a dagger before now.

I've ground about a dozen blades with the new grinder.


All over the board with this batch - Kephart, Nessmuk, EDC, Woodlore... I'm gonna try a Skookum style bush tool.


I inset some dice in these ebony scales for a riverboat gambler's knife....

After the holidays, I'll try a larger drive wheel to speed it up a bit. I'll also order the small wheels attachment. I'll need to figure out a good way to Scandi grind on it.
"The man with the knapsack is never lost." Horace Kephart

Offline hayshaker

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Re: OBM Grinder
« Reply #29 on: December 24, 2016, 04:54:53 AM »
i really like those blanks sarge nice job on those
can't wait to see them finished.
btw how well that belt work i've been wanting to get some.

Offline upthecreek

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Re: OBM Grinder
« Reply #30 on: December 24, 2016, 03:42:43 PM »
Big step forward Sarge. Good to watch. Is your new machine noisy in action?

Creek
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Offline Sarge

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Re: OBM Grinder
« Reply #31 on: December 24, 2016, 06:28:28 PM »
Thanks, hayshaker. That's a 3M Trizact or "Gator" belt. Red (from the forum) recommended them to me early on. They aren't great for course, hard core grinding but are great for finishing. I use them for post-HT clean up and polishing. I do not use them on handle material - wood, micarta, etc.

Creek, the new grinder is surprisingly quiet. It just sorta hums. The Craftsman 2x42 is a lot louder. I think the 1x30 might be louder than the new OBM.
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Offline Sarge

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Re: OBM Grinder
« Reply #32 on: January 04, 2017, 06:43:21 AM »
I ordered and received the small wheels attachment and a second tooling arm. Includes 5 wheels - 1/2", 5/8", 3/4", 7/8" and 1" diameters.



I've only briefly used it but it is rock-solid like the platen attachment, tool rest, etc.

I'm working on a Nessmuk style blade with stabilized walnut scales. Here is a before (sanded to 220 grit) and after (wet-sanded with linseed oil down to 400 grit)


I decided to make a lanyard bead to match the scales. No lathe so I improvised...


Attached it to a bolt and chucked it in a drill.


Walnut with brass - still in progress
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Offline crashdive123

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Re: OBM Grinder
« Reply #33 on: January 04, 2017, 07:30:29 AM »
Looking good.  This may not be an issue with the speed you have your belt running, but if you speed it up be careful not to run your small wheel stuff too long.  Those bearings will get hot.  I don't run mine for more than five minutes before I give it a rest.

Offline Sarge

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Re: OBM Grinder
« Reply #34 on: January 04, 2017, 08:04:37 AM »
Thanks, Crash. I've heard it's pretty easy to smoke the bearings in these small wheels. Even though I'm running them fairly slowly, I'll still take it easy on them. I almost dropped one in the ammo can full of nasty water, metal dust and saw dust. I bet that woulda been tough on the bearings.
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Offline wolfy

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Re: OBM Grinder
« Reply #35 on: January 04, 2017, 08:44:05 AM »
........so, with the newest addition to the grinder, what's the bottom-line tally of frogskins come to now? :shrug:
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Offline upthecreek

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Re: OBM Grinder
« Reply #36 on: January 04, 2017, 10:23:36 AM »
........so, with the newest addition to the grinder, what's the bottom-line tally of frogskins come to now? :shrug:

That's like asking a lady how old she is wolfy   :rofl:

Creek
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Offline Sarge

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Re: OBM Grinder
« Reply #37 on: January 04, 2017, 11:36:37 AM »
........so, with the newest addition to the grinder, what's the bottom-line tally of frogskins come to now? :shrug:
The tool arm and wheel assembly w/ shipping was about $190. The EBay store shows shipping cost for each item but you get a discount on shipping if multiple items are shipped together.

This addition to the previous total of $1,022 puts it at $1,212. That's a lot of $$$ to me but I've been able to stretch the outlay over a few months. I'm very satisfied with it and would buy it again.

I just took a quick look at a KMG set-up and compared (as closely as I could) the costs of the KMG chassis, 2 tooling arms, platen / tool rest assembly and small wheels assembly to my OMB. KMG components + my motor, stand, belts, etc. would be $1,800+ vs. $1,212. I'm not knocking KMG by any means. I have never used or even seen one, just using it to compare costs. 

Still got your finger on the trigger, wolfy?  :popcorn:
"The man with the knapsack is never lost." Horace Kephart

Offline Sarge

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Re: OBM Grinder
« Reply #38 on: January 04, 2017, 11:39:26 AM »
........so, with the newest addition to the grinder, what's the bottom-line tally of frogskins come to now? :shrug:

That's like asking a lady how old she is wolfy   :rofl:

Creek
Just saw this! LOL.
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Offline wolfy

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Re: OBM Grinder
« Reply #39 on: January 04, 2017, 12:20:03 PM »
Sarge, I got'ta tell ya' it seems like my finger is always "on the trigger" for some toy I'm trying to convince myself that I can't live without........then Heather decides that the kitchen that we've been using for the last 25 years is no longer 'up to snuff' and needs an overhaul, we need a new roof, the washing machine suffers an early death, all the vehicles need new tires at the same time, etc. :doh:    Oh, well. :shrug:
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Offline Sarge

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Re: OBM Grinder
« Reply #40 on: January 05, 2017, 06:43:42 AM »
Sarge, I got'ta tell ya' it seems like my finger is always "on the trigger" for some toy I'm trying to convince myself that I can't live without........then Heather decides that the kitchen that we've been using for the last 25 years is no longer 'up to snuff' and needs an overhaul, we need a new roof, the washing machine suffers an early death, all the vehicles need new tires at the same time, etc. :doh:    Oh, well. :shrug:
But what about all that free leisure time you have after retirement?! You should get all that knocked out in no time. Haha
"The man with the knapsack is never lost." Horace Kephart