Surface grinder belt conversion - super easy

[JTknives]

After getting my surface grinder all set up and running smooth I set the wife on the task of surfacing a bunch of D2 stock that I just annealed. My grinder came with a crap ton of wheels in all the colors. But no matter the wheel we tried it still was taking WAY to long to surface off the scale. The scale was not even that bad becaus I ran the 30hr annealing operation with nitrogen flooding so it actually is rather good. But it was taking way to long to get down to nice clean steel and then get a good finish. Then I tryied prepping some damascus billets for restocking and had enough very quickly. I talked to Salem about this issue and he reiterated what he said befor. Switch to belts he said, you will never go back to stone wheels once you try a belt. So I kinda kicked the idea around but realised the linch pin to this entire conversion is finding or modifying a contact wheel to fit the grinders hub. He told me a straight aluminium wheel is best. That sounded hard for me to believe and went ageist what I had seen used in the past. I jokingly said “well if an aluminium wheel is best to bad we can’t just use the stone wheel I have and run a belt around that”. That sparked more conversation and a glimmer of hope that It might not be as crazy as it sounded.

So the next day I ran into the shop and started building. The project went rather quick and easy, I just used what I had on hand. The biggest issue I had was I did not have any pipe that was large enough to fit the round nose of the grinders spindle. So I had to fire up the forge and forge one to shape. I am very very happy with the results and being that I’m using the stone wheel I can dress it And it’s perfectly smooth and true to the spindle. The other thing great about the stone is that ANY ONE can do this conversion. You no longer need an expensive contact wheel to be made to fit your grinder.It’s 1” wide so I just split the belts in half which ends up being better anyways becaus you use the leading edge of the belt while grinding. The other super sweet thing is it runs like a dream on my used belts that are no longer good for the belt grinder. I have been hoarding all my used belts and now I’m glad becaus I have about a life time supply for the surface grinder. The finish is amazing and when you put a 50grit used blaze belt on there it straight up rips steel off. A normal stone would do .0005-.002max and on high aloy steels like D2 it was more like .001 per pass with around a .002 step over. Belts will take as much as you give it at a full step over. I’m not sure what the max step over is on my machine but it over .100 and with a .010 depth of cut per pass its impressive.

Here are the pictures of the build.

Here it is all assembled, I did not have a spring so I used an air cylinder and plugged the holes with valves. This is actually really handy. I can open them and the arm comes complete down. Or I could even pump air in and increase the weight. I find that that the two values are great for the weight I need. I can open the top and just have the bottom of the cylinder pull a vacuum which is a nice amount of weight. The slick thing about that is the force stays the same through the entire stroke. The force is just the 14.7lbs of 1 atmosphere times the surface area of the of the upper part of the piston. If I want more force I close the upper valve and now I have a vacuumed on one side and compression on the other. So it’s rather slick and will defiantly get used on other projects in the future.

All the pivots are shoulder bolts with bearings. This keeps the bolts from loosening.

So I’m very happy with the conversion and will not go back to using wheels. But if I ever do need the precision of a wheel all I have to do is pop off the belt and I got a wheel right there to use. So it’s quite handy to be able to switch back and forth in a matter of seconds.

 

[autogateman]

The wheel won’t tear up the inside of the belt?

 

[JTknives]

No it won’t. At first it was but that was because it was tracked over the edge of the wheel. I quickly found out that a standard crowned tracking wheel is a no go. I could not get it to track using that wheel. I replaced it with a warn out bemount 2” contact wheel and all is good. But even before the switch it was not messing up the belt much at all.

 

[Natlek]

I don t think so , to tear belt must slip ? No chance that belt will slip on that wheels ...............brilliant idea

 

[kuraki]

Isn't your grinder an automatic?

ETA: Reading a little closer. .001" depth of cut and .002" stepover? You're not running coolant?

When I grind annealed steel I'm grinding .025" doc and .005" stepover. Then just walk away and do something else for 5 minutes.

 

[Natlek]

@JTknives , I think that now you need this tool ............but maybe you already have it

 

[Tom Lewis]

Thanks for the pictures, very nice work. I also changed my surface grinder to run a belt. For me the belt works much better than the stone.

 

[JTknives]

Yeah I’m not using coolant on this grinder. Yes it is automatic but still takes a long time at such shallow DOC and around .020 step over. How are you doing a .025 dec on a surface grinder even with a .005 step over.

 

[autogateman]

That had to be a typo. No way he’s taking .025 doc on a surface grinder. At least I’ve never seen one that could.

 

[Ken H>]

Maybe he meant .005" DOC with a .025" stepover?

JT, is that a hydraulic cylinder you're using to put pressure on the tracking wheel rather than a spring? From the size of it you can sure get the "pressure" applied {g}

and good work coming up with the change over to belts.

 

[Lieblad]

Nice!
Hope that up facing aircylinder seal holds up against swarf.

 

[JTknives]

It’s a pneumatic cylinder. I have just capped off both ports with the cylinder completely retracted. This creats a vacuum in one area and pressure in the other when I pull on the arm. Works really good. I could actualy pressurise the cylinder with a fitting if I wanted more tension. Air is nice because you can let it out and put the belt on then pump it back up. If you had a regulator set to X pressure you could run it through a valve and one way would let it down and the other way would tension it.

 

[kuraki]

No typo. You need to use coolant and a fryable wheel. The leading edge of the wheel breaks down as it cross feeds. This is why I don't understand the penchant for converting to belts especially on an automatic. Unless you're determined to run it dry.

Also the size of the machine. Nothing under a 10" wheel will have the hp to do it without slowing down.

 

[JTknives]

I think Salem is doing .025 doc at .120 step over.

 

[HSC ///]

This is why I don't understand the penchant for converting to belts especially on an automatic.

I worked with two ABS MS both who have belt conversion surface grinders. From what I can tell, the primary reason to do the conversion is the flexibility of surfacing various materials and setups that a belt can give you. You can surface stag, handles, liners, folder work, pretty much anything....
Because they are not machinists per se, they are master knife makers. The belt grinder conversion is simply more efficient for them for the requirements of quick and accurate surfacing.

 

[Karl B. Andersen]

I run my SG daily - for everything.
.003" depth and about .100" step over using a 1" 60 grit belt.
I never save used belts from grinding. Just keep dedicated NEW belts for the SG and dress them to make them FLAT. Do you want things flat? There's no telling now irregular the belts are when they've already been abused.
Gator belts are your friend.

 

[kuraki]

I worked with two ABS MS both who have belt conversion surface grinders. From what I can tell, the primary reason to do the conversion is the flexibility of surfacing various materials and setups that a belt can give you. You can surface stag, handles, liners, pretty much anything....
Because they are not machinists per se, they are master knife makers. The belt grinder conversion is simply more efficient for them for the requirements of quick and accurate surfacing.

That makes a lot of sense.

 

[JTknives]

I run my SG daily - for everything.
.003" depth and about .100" step over using a 1" 60 grit belt.
I never save used belts from grinding. Just keep dedicated NEW belts for the SG and dress them to make them FLAT. Do you want things flat? There's no telling now irregular the belts are when they've already been abused.
Gator belts are your friend.

But belt flatness is not a big deal when, A: your prepping billets and B: you run your belt all the way across the steels surface. I do love the gator belts on the surface grinder. You can dress them just like a stone with a diamond point.

 

[Karl B. Andersen]

I worked with two ABS MS ...... The belt grinder conversion is simply more efficient for them for the requirements of quick and accurate surfacing.

There are a LOT! of people out there using belt conversions who have nothing to do with the ABS, and/or are not MS.
The precision obtainable by many folder makers using belt conversions is wide spread.
Using just a little common sense and a 2-3 belt progression, the sky is the limit.
I would be hard-pressed these days to make any knife without mine.

 

[john april]

awesome idea !