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I just got material to make my own rotary platen, and was going to do the exact same thing. How's the flat platen work for you?
Crowd Dev? New Platen design
- Thread starter Brock Cutlery
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I'm gonna tell you guys one more time. 
There's a much easier way to make a "soft platen" like the super expensive carbide backed rotary platen, that's just as effective, and costs 1/30th of the cost.
Simply glue extra hard industrial felt to a flat platen, you can get it in 2" wide strips from McMaster.
This concept isn't new, the guy that taught me to make slipjoints (Daniel Warren MS), has been using something similar for decades, originally we used rubber drive belting glued to a flat platen, with 3m micron (mylar) belts, turned backwards, glued on to them, as a consumable, which allowed the belts you're cutting with to ride over the rubber, of course, after a few uses it would have to be replaced, and you had to keep the tension and speed low and couldn't really use course belts.
With the felt, which is 1/4" thick, you can run the belts right on top of them, at pretty high speeds, just make sure and use a good strong glue and let it cure fully.
You can do convex grinds on this, or what we use it for, is blending any inconsistencies for a bling ass belt finish at higher grits (400, 800, or 1200) that look much nicer than a scotchbrite or structured abrasive belt finish. It can also save you some hand sanding time if you're doing a hand finish. It's the same idea behind the scrim backed high grit belts, or cork backers, yet much more effective.
Do you guys need a photo?
There's a much easier way to make a "soft platen" like the super expensive carbide backed rotary platen, that's just as effective, and costs 1/30th of the cost.
Simply glue extra hard industrial felt to a flat platen, you can get it in 2" wide strips from McMaster.
This concept isn't new, the guy that taught me to make slipjoints (Daniel Warren MS), has been using something similar for decades, originally we used rubber drive belting glued to a flat platen, with 3m micron (mylar) belts, turned backwards, glued on to them, as a consumable, which allowed the belts you're cutting with to ride over the rubber, of course, after a few uses it would have to be replaced, and you had to keep the tension and speed low and couldn't really use course belts.
With the felt, which is 1/4" thick, you can run the belts right on top of them, at pretty high speeds, just make sure and use a good strong glue and let it cure fully.
You can do convex grinds on this, or what we use it for, is blending any inconsistencies for a bling ass belt finish at higher grits (400, 800, or 1200) that look much nicer than a scotchbrite or structured abrasive belt finish. It can also save you some hand sanding time if you're doing a hand finish. It's the same idea behind the scrim backed high grit belts, or cork backers, yet much more effective.
Do you guys need a photo?
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That looks really nice. If it were able to either swing out of the way, or have a quick removal system I'd likely be a buyer. I think if you cut the end off as you mentioned it would weaken the rest significantly.
Maybe I'll ping him. Thanks for the info!
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Also, in case it sounds like I'm being negative (not my intent), I wanted to say I do really like the removable platen idea. Although I would stick with two rods for alignment purposes, or use a square rod.
This advantage of something like this is speed of reconfiguration, if you have to twist and realign the platen each time, it'd be useless to me.
I'd try to focus on keeping it modular so you can add accessories, as opposed to making it have too many features at once.
I still have one of those flat platen plates from Polar Bear that you can run a 4" and 2" wheel or whatever on, and supposedly switch out from slack belting and turn it for this or that wheel. Yeah on paper that seems nice, but in use, it's simply quicker to have 2" contact wheels on my flat platen (which I use without moving the platen, because then I'd have to move it back), or switch out to a 4" wheel or whatever on it's own tooling arm.
It's simply quicker, because no matter what, you're likely to remove the belt, adjust, put the belt back on, fiddle, etc. Just my 2c.
I would buy/build one of the original design you posted though Kuraki, just to keep from having to take the damn socket head bolts out of my current setup, and have more clearance for slack belting. I'm also using one of Nathan's flat platens with a chiller, and much prefer it to a glass platen.
This advantage of something like this is speed of reconfiguration, if you have to twist and realign the platen each time, it'd be useless to me.
I'd try to focus on keeping it modular so you can add accessories, as opposed to making it have too many features at once.
I still have one of those flat platen plates from Polar Bear that you can run a 4" and 2" wheel or whatever on, and supposedly switch out from slack belting and turn it for this or that wheel. Yeah on paper that seems nice, but in use, it's simply quicker to have 2" contact wheels on my flat platen (which I use without moving the platen, because then I'd have to move it back), or switch out to a 4" wheel or whatever on it's own tooling arm.
It's simply quicker, because no matter what, you're likely to remove the belt, adjust, put the belt back on, fiddle, etc. Just my 2c.
I would buy/build one of the original design you posted though Kuraki, just to keep from having to take the damn socket head bolts out of my current setup, and have more clearance for slack belting. I'm also using one of Nathan's flat platens with a chiller, and much prefer it to a glass platen.
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Yeah, I don't plan on doing it, but it's pretty beefy, probably like 3/8 thick steel. It would likely still be pretty stiff. Swinging the whole thing out of the way is better though.
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I'm thinking square rod now too. Just seems easier to put together. Weld or screw a platen mount plate with cutout for chiller tubes if so inclined. Seems easier, and can have one quick tighten lever. Good point sir.
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I would like to know where i could get this felt. I've been using unicorn pelt, but it's hard to come by since i now have 10 year old twin girls.I'm gonna tell you guys one more time.
There's a much easier way to make a "soft platen" like the super expensive carbide backed rotary platen, that's just as effective, and costs 1/30th of the cost.
Simply glue extra hard industrial felt to a flat platen, you can get it in 2" wide strips from McMaster.
This concept isn't new, the guy that taught me to make slipjoints (Daniel Warren MS), has been using something similar for decades, originally we used rubber drive belting glued to a flat platen, with 3m micron (mylar) belts, turned backwards, glued on to them, as a consumable, which allowed the belts you're cutting with to ride over the rubber, of course, after a few uses it would have to be replaced, and you had to keep the tension and speed low and couldn't really use course belts.
With the felt, which is 1/4" thick, you can run the belts right on top of them, at pretty high speeds, just make sure and use a good strong glue and let it cure fully.
You can do convex grinds on this, or what we use it for, is blending any inconsistencies for a bling ass belt finish at higher grits (400, 800, or 1200) that look much nicer than a scotchbrite or structured abrasive belt finish. It can also save you some hand sanding time if you're doing a hand finish. It's the same idea behind the scrim backed high grit belts, or cork backers, yet much more effective.
Do you guys need a photo?
JDWARE
Knifemaker / Craftsman / Service Provider
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- Nov 28, 2011
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I'm gonna tell you guys one more time.
There's a much easier way to make a "soft platen" like the super expensive carbide backed rotary platen, that's just as effective, and costs 1/30th of the cost.
Simply glue extra hard industrial felt to a flat platen, you can get it in 2" wide strips from McMaster.
This concept isn't new, the guy that taught me to make slipjoints (Daniel Warren MS), has been using something similar for decades, originally we used rubber drive belting glued to a flat platen, with 3m micron (mylar) belts, turned backwards, glued on to them, as a consumable, which allowed the belts you're cutting with to ride over the rubber, of course, after a few uses it would have to be replaced, and you had to keep the tension and speed low and couldn't really use course belts.
With the felt, which is 1/4" thick, you can run the belts right on top of them, at pretty high speeds, just make sure and use a good strong glue and let it cure fully.
You can do convex grinds on this, or what we use it for, is blending any inconsistencies for a bling ass belt finish at higher grits (400, 800, or 1200) that look much nicer than a scotchbrite or structured abrasive belt finish. It can also save you some hand sanding time if you're doing a hand finish. It's the same idea behind the scrim backed high grit belts, or cork backers, yet much more effective.
Do you guys need a photo?
Javan, found the "hard felt" material on the McMaster site. Can you be more specific with the felt you recommend? The "Hard Felt" is offered in 50A, 55A and 80A durometer hardeness, 1/4" thick ..... for temps up to 200F, and only in sheets, not strips. They also offer "Firm Felt" in 2" strips, 1/4" thick, in 25A and 35 A durometers, also for temps up to 200 F. And they offer "Hi Temp" felt (no durometer rating) for temps up to 600F in 2" strips 1/8" thick
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Get the 80A Duro stuff, the hardest felt you can get. The less hard have too much "give". Any of these options still require some technique if you're using it for refining as opposed to convexing. I use the 1/4" thick stuff. You used to be able to get it in 2" strips but now all they offer is squares, still, it's easy to cut it 2" wide with a knife and a straight edge.
I bought some of the high temp stuff and it was way too soft.
I bought some of the high temp stuff and it was way too soft.
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Also, I'm pretty certain even harder felt can be obtained, and stuff that's rated to higher temps, this is just what's easily found via McMaster.
I used to know a guy that was a VP at an industrial felt plant, and was amazed to learn of all the variations, and uses for this stuff. I've seen stuff listed as Extra Extra Firm before however, but I think it'd require some tracking down. I'd actually like this stuff to be a little harder. The rubber belting was harder and actually a little easier to use, but the maintenance was a pain in the ass.
I used to know a guy that was a VP at an industrial felt plant, and was amazed to learn of all the variations, and uses for this stuff. I've seen stuff listed as Extra Extra Firm before however, but I think it'd require some tracking down. I'd actually like this stuff to be a little harder. The rubber belting was harder and actually a little easier to use, but the maintenance was a pain in the ass.
JDWARE
Knifemaker / Craftsman / Service Provider
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Alan Davis Knives
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It works great, I was just doing it to try out and used mild steel but will probably invest in a carbide platen soon. It does get rid of the belt bump completely!
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Javan, that's great info. I'll be getting some of that felt and taking a serious look at a chiller platten. I've been doing a pile of subtly convexed blades recently, and that felt sounds perfect for finish grinding them.
Nathan the Machinist
KnifeMaker / Machinist / Evil Genius
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Hey gang I'm a little late to the party here.
Somebody smarter than me figured out that a shallow S grind has some cutting characteristics that works well for certain cutting tasks. You're getting some of the reduced drag associated with a convex grind at the leading and trailing shoulders of the grind without the additional meat and thickness in the middle. I believe this reduces binding and improves penetration in some cuts such as the 2X4, rope and water bottles etc. This all stems from studying and trying to duplicate the geometry of a knife I have here with three world cutting championships and I believe a world record on it in order to reproduce its cutting characteristics for a Bladesports collaboration we're working on. This led us to this:
It's a radial platen with a tiny radius platen behind it that does a pretty fair job making a good S grind.
That gets hot at hell at speed though.
So we experimented with a layout like this so I could use a regular radius platen and chiller.
If I remember right, that was a 70" rubber belt under the 72" abrasive belt. Only the abrasive belt was run over the tracking wheel, the rubber belt went direct, which allows you to tension them separately.
That layout, when used with a radius platen and chiller, functioned well at high speed without overheating but it's a pain in the ass to setup and I couldn't find the correct width belt at that length.
The concept of a rubber belt over a flat or curved platen works and has a lot of applications. We have a few hundred knives with it under our belt now. I can tell you it eliminates splice bump so I no longer scrape the grit off the splice. We get a smoother finish. It's difficult to fracture a grain so you can't "use up" a belt very well, so we save them for regular flat platen work such as grinding the flats. It's noisy and smelly at first but a rubber belt breaks in after a few days and quiets down. There are good and not so good rubber belts out there, find a good one or it has its own splice bump problems. A hardened A2 platen hasn't worn out after hundreds of hours of production use so it looks to me that carbide might not be necessary.
^ I hope that's useful to some of you.
We're in the middle of a run producing a batch of KMG compatible chillers, end radius flat platens, regular flat platens, radius platens and C plates for 8 and 10" platens. I plan to add some kind of a feature to the 8" C plate to accommodate a 3rd wheel just for running a belt over the platen so I can use a standard platen and chiller with a rubber belt.
Somebody smarter than me figured out that a shallow S grind has some cutting characteristics that works well for certain cutting tasks. You're getting some of the reduced drag associated with a convex grind at the leading and trailing shoulders of the grind without the additional meat and thickness in the middle. I believe this reduces binding and improves penetration in some cuts such as the 2X4, rope and water bottles etc. This all stems from studying and trying to duplicate the geometry of a knife I have here with three world cutting championships and I believe a world record on it in order to reproduce its cutting characteristics for a Bladesports collaboration we're working on. This led us to this:
It's a radial platen with a tiny radius platen behind it that does a pretty fair job making a good S grind.
That gets hot at hell at speed though.
So we experimented with a layout like this so I could use a regular radius platen and chiller.
If I remember right, that was a 70" rubber belt under the 72" abrasive belt. Only the abrasive belt was run over the tracking wheel, the rubber belt went direct, which allows you to tension them separately.
That layout, when used with a radius platen and chiller, functioned well at high speed without overheating but it's a pain in the ass to setup and I couldn't find the correct width belt at that length.
The concept of a rubber belt over a flat or curved platen works and has a lot of applications. We have a few hundred knives with it under our belt now. I can tell you it eliminates splice bump so I no longer scrape the grit off the splice. We get a smoother finish. It's difficult to fracture a grain so you can't "use up" a belt very well, so we save them for regular flat platen work such as grinding the flats. It's noisy and smelly at first but a rubber belt breaks in after a few days and quiets down. There are good and not so good rubber belts out there, find a good one or it has its own splice bump problems. A hardened A2 platen hasn't worn out after hundreds of hours of production use so it looks to me that carbide might not be necessary.
^ I hope that's useful to some of you.
We're in the middle of a run producing a batch of KMG compatible chillers, end radius flat platens, regular flat platens, radius platens and C plates for 8 and 10" platens. I plan to add some kind of a feature to the 8" C plate to accommodate a 3rd wheel just for running a belt over the platen so I can use a standard platen and chiller with a rubber belt.
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I'm gonna tell you guys one more time.
There's a much easier way to make a "soft platen" like the super expensive carbide backed rotary platen, that's just as effective, and costs 1/30th of the cost.
Simply glue extra hard industrial felt to a flat platen, you can get it in 2" wide strips from McMaster.
This concept isn't new, the guy that taught me to make slipjoints (Daniel Warren MS), has been using something similar for decades, originally we used rubber drive belting glued to a flat platen, with 3m micron (mylar) belts, turned backwards, glued on to them, as a consumable, which allowed the belts you're cutting with to ride over the rubber, of course, after a few uses it would have to be replaced, and you had to keep the tension and speed low and couldn't really use course belts.
With the felt, which is 1/4" thick, you can run the belts right on top of them, at pretty high speeds, just make sure and use a good strong glue and let it cure fully.
You can do convex grinds on this, or what we use it for, is blending any inconsistencies for a bling ass belt finish at higher grits (400, 800, or 1200) that look much nicer than a scotchbrite or structured abrasive belt finish. It can also save you some hand sanding time if you're doing a hand finish. It's the same idea behind the scrim backed high grit belts, or cork backers, yet much more effective.
Do you guys need a photo?
Very interesting.... I wouldn't mind seeing some pics.
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Learned a little 3D modeling thanks to DesignSpark and YouTube.
This is a rough draft of my redesigned platen frame assembly for the Esteem grinder. Kudos for the 3 inch wheel suggestion! This is a great dev gang. Thanks BF!
I'm not worrying about the rotary stuff, I have one already. That is another thread / project.
I put a tool arm mount next to the platen mount bar but realized it needs to go on the other side of the frame so as not to interfere with belt changes. Oh well.. I'll move it.
This is designed to fit the Esteem grinder, which does not have a platen frame with a centered tool arm. It could be easily modified for a center mounted config. My current platen frame mounts to a drilled tool arm with a locking bolt to lock the platen frame rod in place. It seems to be a pretty effective mount so far. After 3 years of grinding I have never had it move unexpectedly. It also frees up the right side of the frame to work with the platen mount bar in this design.
This frame should allow for the longer 10 inch platen I have from Nathan. I might need to tweak the bar mount a bit still. That platen has the mount bolt holes on the low side, so the top hangs. Nothing wrong with that I think. I don't grand at the top with any serious pressure. It's just not a centered mount pattern.
Platen shown is standard 8 inch.
2 inch contact wheel on top, 3 inch on bottom.
I was going to go build this thing, but after messing with the modeling, I realized I want to play with it a while and ensure it is as ready for prime time as possible before the build.
This is a rough draft of my redesigned platen frame assembly for the Esteem grinder. Kudos for the 3 inch wheel suggestion! This is a great dev gang. Thanks BF!
I'm not worrying about the rotary stuff, I have one already. That is another thread / project.
I put a tool arm mount next to the platen mount bar but realized it needs to go on the other side of the frame so as not to interfere with belt changes. Oh well.. I'll move it.
This is designed to fit the Esteem grinder, which does not have a platen frame with a centered tool arm. It could be easily modified for a center mounted config. My current platen frame mounts to a drilled tool arm with a locking bolt to lock the platen frame rod in place. It seems to be a pretty effective mount so far. After 3 years of grinding I have never had it move unexpectedly. It also frees up the right side of the frame to work with the platen mount bar in this design.
This frame should allow for the longer 10 inch platen I have from Nathan. I might need to tweak the bar mount a bit still. That platen has the mount bolt holes on the low side, so the top hangs. Nothing wrong with that I think. I don't grand at the top with any serious pressure. It's just not a centered mount pattern.
Platen shown is standard 8 inch.
2 inch contact wheel on top, 3 inch on bottom.
I was going to go build this thing, but after messing with the modeling, I realized I want to play with it a while and ensure it is as ready for prime time as possible before the build.
kuraki
Fimbulvetr Knifeworks
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My only concern with that would be the square channel/bar fit must be very close, especially with the clamp on the top. Any clearance will translate into perpindicularity runout between the platen face and the wheel axis. But, if you remove the work rest/tool arm mount and put the clamp on the side, it will eliminate that by constraining the platen perp to the wheels.
Even .015 of runout in this way is aggravating to deal with, because it essentially results in greater belt tension on one side of the platen than the other, making pluge radii all but impossible to get symmetrical on left and right sides. I found that out the hard way.
Even .015 of runout in this way is aggravating to deal with, because it essentially results in greater belt tension on one side of the platen than the other, making pluge radii all but impossible to get symmetrical on left and right sides. I found that out the hard way.
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Thanks for that Tip John. I will be moving that rest, and I'll move the clamp back to the side. I'll also ensure a very snug fit on the bar. Many thanks!
PEU
Gaucho Knifemaker
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- Aug 6, 2006
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Hi guys, I've been using this triangle the last years and its like having two grinders in one, you have a platen, and two more positions for handle work:
Full gallery here: https://imgur.com/a/h7AHP
Pablo
Full gallery here: https://imgur.com/a/h7AHP
Pablo
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Hey gang I'm a little late to the party here.
Somebody smarter than me figured out that a shallow S grind has some cutting characteristics that works well for certain cutting tasks. You're getting some of the reduced drag associated with a convex grind at the leading and trailing shoulders of the grind without the additional meat and thickness in the middle. I believe this reduces binding and improves penetration in some cuts such as the 2X4, rope and water bottles etc. This all stems from studying and trying to duplicate the geometry of a knife I have here with three world cutting championships and I believe a world record on it in order to reproduce its cutting characteristics for a Bladesports collaboration we're working on. This led us to this:
It's a radial platen with a tiny radius platen behind it that does a pretty fair job making a good S grind.
That gets hot at hell at speed though.
So we experimented with a layout like this so I could use a regular radius platen and chiller.
If I remember right, that was a 70" rubber belt under the 72" abrasive belt. Only the abrasive belt was run over the tracking wheel, the rubber belt went direct, which allows you to tension them separately.
That layout, when used with a radius platen and chiller, functioned well at high speed without overheating but it's a pain in the ass to setup and I couldn't find the correct width belt at that length.
The concept of a rubber belt over a flat or curved platen works and has a lot of applications. We have a few hundred knives with it under our belt now. I can tell you it eliminates splice bump so I no longer scrape the grit off the splice. We get a smoother finish. It's difficult to fracture a grain so you can't "use up" a belt very well, so we save them for regular flat platen work such as grinding the flats. It's noisy and smelly at first but a rubber belt breaks in after a few days and quiets down. There are good and not so good rubber belts out there, find a good one or it has its own splice bump problems. A hardened A2 platen hasn't worn out after hundreds of hours of production use so it looks to me that carbide might not be necessary.
^ I hope that's useful to some of you.
We're in the middle of a run producing a batch of KMG compatible chillers, end radius flat platens, regular flat platens, radius platens and C plates for 8 and 10" platens. I plan to add some kind of a feature to the 8" C plate to accommodate a 3rd wheel just for running a belt over the platen so I can use a standard platen and chiller with a rubber belt.
great info thanks Nathan. I'm definitely interested in the chiller and platens. Will you be starting a thread on these or just listing them on your site?
ps. your inbox is full