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2 x 36 Grinder for Knifemaking?


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Hey everyone, 

 

Firstly, just wanted to say how great this forum has been. I'm a beginner,  I've made now 5 or 6 knives that have been so much better for all the knowledge I've gotten from this forum. 

 

My first knives were made with what I had lying around - a handheld belt sander for woodworking that I turned upside down and clamped to the bench and it works fine (aka slow and ineffective but works with persistence) but I'm looking to upgrade to something a bit more suitable now that I know I like knifemaking. My question is: has anyone had any experience with a 2 x 36 inch multitool attachment on a bench grinder set up (like this https://www.totaltools.com.au/145906-multitool-po362-attachment-suits-tm400-200-itm-200mm-bench-grinder-po362200)? Apparently the orientation of the attachment can be changed so that the platen is straight upright in the more conventional way. To me it seems like it would do the job, but I haven't exactly been doing this for long so would love to know what others think. I'm asking about this specifically because a lot of the budget options that are discussed in the forum are hard to find in Australia (eg smaller Grizzly or Jet units), and as a student the  $500 AUD (or $315 USD) that this costs is about the top of the budget. 

 

Some alternatives I've got available are a 4 x 36 like for woodworking (that seems to not be very popular) or something like this https://www.bunnings.com.au/ryobi-370w-bench-grinder-sander_p6210415

 

Would love to hear some thoughts or any alternative suggestion if any Australian readers know any better! 

 

Cheers 

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Im sure that that would work, but is a little underpowered . rule of thumb for metal grinding is 1hp (750watt) per inch of belt width,

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I have also looked at these attachments as I've also used a 4x36 wood sander for years for metal work.  It's done the jobs I've asked of it over the years, but it is meant for wood work. That means I've had to strip all the plastic from it, it is only like a 1/4 hp.  I would say that if your looking to upgrade, get something like the grinder attachment that is better to use for grinding metal. I've been looking at them for a while, but I do very little knife grinding over all.

 

However if your serious, a 1hp 2x72 can't be beat.  I've used a few at my local craft school for many different projects over the years. As hobbyist, I look at a 2x72 as a wish list item. I wish I could have one, but for the price of one and how often I would use it could one of those attachments work for me on the grinder I already have.  

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I must say, that multitool attachment looks pretty good.  My 2x72 is a 1hp, and it is underpowered, but it still gets the job done.  With a 36" belt you have half the surface area to try and stall out, so 600W should work, or, (and here's a thought!) a C-frame electric motor might be able to bolt right to the belt attachment, giving you the chance to use more power..  The Ryobi is out, that's not a real tool in any sense unless you're making tiny models from wood and tin.  I used a 4x36 for a few years, until I figured out files are faster and they don't have bearings to get clogged with metal dust.  

 

My main concern with the Multitool is availability of belts.  What can you get to fit it?  

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At $500 you are within spitting distance of the Grizzly grinder which is probably going to serve you better.

 

This is a rare time when I'll push back on Alan a bit.  Most of the load for knife making will come from the 2" belt width  times however much length in contact with the work.  The rest of the belt isn't really adding that much load.  I think a 2x36 running at 600W would feel just as weak as a 2x72 running that sized motor.

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I own one of these and tried it for knife making. It hasn’t worked out for me. I’ve had it for over two years now. I bought better files. Not to say I don’t use it. But files do most of my work. You can get belts from Jantz or amazon. Not as many grits available for it like a 2x72. The drawback to this thing, for me, is bad tracking and horrible vibration at high speeds. Makes it impossible for me to grind good bevels. There are some things I know I could do to make it better but I don’t want to put in the time and effort. I use it a lot on handles and for leatherwork. Steel, not so much. Attached a pic. It doesn’t look like this now.

8EDDBE44-709E-4E84-AF73-F47FB6E19594.jpeg

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1 hour ago, Brian Dougherty said:

This is a rare time when I'll push back on Alan a bit.

 

By all means, do so when needed!  :lol:

 

38 minutes ago, Jon Bishop said:

The drawback to this thing, for me, is bad tracking and horrible vibration at high speeds.

 

And that's exactly what I needed to hear.  Since the one Antony linked is not variable speed, sounds like it will be of even less use than a 4x36.  

 

Antony:  Talk to Rob Toneguzzo here on the forum.  He's up by Darwin, and his friends recently built a 2x72 belt grinder.  He may be of service in sourcing parts.  

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Posted (edited)

I will add on the tracking. It will track true but getting it there is a pain. I’ve destroyed new belts trying to get it to track. In the  picture, on the left of the belt you can see a little paddle. This is the tracking adjustment. It is very sensitive. One way or the other too far and it will shred a belt fast. I’ve taken to using a wrench to tap on it up or down to get it to track at the slowest speed. If I want to increase speed for grinding steel I increase slowly and tap in the direction it needs to go. The thing is you will tap too hard because you can’t see anything changing. (The tracking varies by speed by the way.) Then the paddle loses its tension and goes loose. Belt shredded. My setup is good at lowest speed to about 1/3 up. Anything faster and it’s horrible. You can still remove metal with it. But I can’t “hog” off steel with it. At higher grits on slow speed it will considerably cut down on hand sanding. I forge by the way. If I were doing stock removal an angle grinder and good files would work better. Hope this helps.

 

Jon

Edited by Jon Bishop
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Posted (edited)

Thanks everyone for all the advice! 

 

9 hours ago, Brian Dougherty said:

At $500 you are within spitting distance of the Grizzly grinder which is probably going to serve you better.

 

 

Do you know which model you mean? Other than that Grizzly doesn't supply to Australia, it would be good to know in case one ever pops up! The G1015, which seems to be suggested a lot, is $600 USD which once you convert to AUD is well past the budget unfortunately. Unless you're referring to either their 1x42 or 1x30 models? 

 

Total beginner question here but what exactly does bad tracking mean? I know tracking means getting the belt to stay centered over the platen so does bad tracking mean that while grinding the belt can move too far to either side and get shredded by getting caught up in the wheels? 

 

Jon, great to find someone who has one of these! Yes I make my knives with stock removal. Do you think that even with your setup working at its best (as in low speeds), you would still prefer to use files for the bevel? I'm sure I could find the attachment and a variable speed grinder so it's still an option I think. And as you mentioned, one of these is useful for handles and other wood working purposes, which I do a lot of, which is why it got me interested in the first place. Gameco down here stocks a good supply of 2x36 belts which fixes that problem. 

 

Thanks again everyone

 

 

 

Edited by Antony Y
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There was a group buy of 2" x 36" Multitool attachments on the now-defunct British Blades forum a few years ago. I think it was an importers stock clearance, but the price was a fraction of list (I think they were about 60 quid each). I bought 3 of them, and a 4" x 36.

 

One of the guys on the forum came up with a kit to fit the MT to an IEC metric 80-frame foot-and-face-mount motor. It was a pretty simple kit: basically a few bits of plasma-cut 6mm plate, a few fasteners and a bit of 1mm shim stock to wrap round the 19mm motor shaft and adapt it to the 3/4" bore of the wheel. I bought 2 of them. They worked brilliantly, though the shim thing was a lot of faffing about and I just used Loctite on the second one I built.

 

I used 0.75 kW (1 HP), 3-phase, 4-pole motors because I had a number of different VFDs available. If I was doing it again now, I would use a 1.1 kW (1.5 HP) 2-pole motor and a Sensorless Vector VFD.

 

I mounted the third attachment to a really cheap, nasty 1/2 HP bench grinder. It beats the wotsits out of having no belt grinder, but is definitely underpowered. I had a try of one that someone had put on a 900-Watt bench grinder and that was a properly useful tool in a fab shop.

 

The MT kits we had were for a 3/4" shaft with reducing bushes supplied to fit smaller sizes. I gather there have been other kits that will only go to a maximum 5/8" shaft, so cannot be readily used on an 80-frame motor. It's worth checking maximum shaft size on the one you are considering.

 

In your shoes, I'd get the Multitool, mount it to a cheap/available bench grinder, then save for a motor and VFD. Have a think about making an adaptor plate in the meantime. That way, the only thing that you'd need to buy that wasn't on the direct upgrade path would be the cheap bench grinder.

 

Even on a 1/2 HP bench grinder (a little under 3000 RPM, assuming you are on 50 Hz mains), it's able to stock-remove for knifemaking faster than most beginners can do with files. It does mean that you get to develop grinding skills, rather than filing skills.

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8 hours ago, Antony Y said:

Do you know which model you mean? Other than that Grizzly doesn't supply to Australia, it would be good to know in case one ever pops up! The G1015, which seems to be suggested a lot, is $600 USD which once you convert to AUD is well past the budget unfortunately. Unless you're referring to either their 1x42 or 1x30 models? 

 

Yeah, the G1015 is the one I meant.  I didn't catch that you were talking $AUD.  You can get the G1015 for $500US or less when they run sales.  I almost bought one for $475 about 4 years ago, but decided to save for something better.

 

There are a number of DIY 2x72 plans out there if you can get the parts fabricated.  

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Hi, Antony. Yes I would still use files. My set up might not be greatest for this belt grinder. It’s just a cheap lowes bench grinder. The thing is, at slow speed with a 36 grit belt, on soft steel that will drill, it would take awhile to do stock removal on something like 3/16”x 1-1/4” steel. Most likely two to three belts. High speed will take more metal off. But I can’t handle it with set up. Thinner  narrower stock it could do well. As I said I forge and set the bevels that way. Say a 4” blade 3/4” tall by 1/8” thick pre beveled during forging, I’m not really gaining anything with this grinder the way it runs. I can finish file a blade that size with good files in a reasonable amount of time. Without a lot of risk ruining the bevel. I will use it on the tang of hidden and thru tangs and also contour work on full tangs. It has its uses for sure. I like Pferd files with a safe edge. If you have more questions let me know. I’ll help the best I can.

 

Jon

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  • 4 weeks later...

4EA1FBD8-2C2A-4032-8BB9-F0CFC20FD32A.jpegHi Antony, like you I’m very much a beginner. I’ve bought one of those grinder/linisher attachments from Hare and Forbes in Melbourne Australia, about $240, I think it’s great. I did have it running with a wire wheel in the opposing spindle, the vibration made it unusable, removed the wire wheel and it runs perfectly. The tracking adjustment is sensational. Having said all of that I’m yet to grind a knife with it, nor have I ground any other knife. I’ve moved it over to the left hand side of the grinder, installed it vertically so as the platan faces forward. I’m going to fabricate a table and a file guide before I attempt my first grind. Juju

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