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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Posted to rec.crafts.metalworking
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I've got an old piece of granite counter top I glue wet or dry sand paper to
with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. |
#2
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Posted to rec.crafts.metalworking
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On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe"
wrote: I've got an old piece of granite counter top I glue wet or dry sand paper to with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. Greetings Bob, I have had very good luck over the years using 3M wetordry, it holds up quite well when wet with water, kerosene, stoddard solvent, and alcohol. So maybe, if you haven't tried it, you might want to buy a sheet or two. As to the emery cloth, I use some 3M stuff that costs more but is way more economical than the cheap stuff. I buy it in rolls but I'd be surprised if MSC doesn't have it in sheets. I don't know if the Cubitron abrasive is available on sheets but if it is I would say try some. I have some Cubitron flap discs for my angle grinders and they way out perform anything I have ever used. The abrasive cuts faster and lasts longer. In fact, the discs cut way faster and way longer. Eric |
#3
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Posted to rec.crafts.metalworking
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wrote in message ...
On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: I've got an old piece of granite counter top I glue wet or dry sand paper to with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. Greetings Bob, I have had very good luck over the years using 3M wetordry, it holds up quite well when wet with water, kerosene, stoddard solvent, and alcohol. So maybe, if you haven't tried it, you might want to buy a sheet or two. As to the emery cloth, I use some 3M stuff that costs more but is way more economical than the cheap stuff. I buy it in rolls but I'd be surprised if MSC doesn't have it in sheets. I don't know if the Cubitron abrasive is available on sheets but if it is I would say try some. I have some Cubitron flap discs for my angle grinders and they way out perform anything I have ever used. The abrasive cuts faster and lasts longer. In fact, the discs cut way faster and way longer. Eric **************** I may have found my problem. I pulled out a sheet today and just set it on my granite to quick touch up some parts. I figured it would slide around, but it would be ok for a couple parts. It was ok for a couple parts, but amazingly it didn't slide around much at all. Then I looked at it and discovered its not wet or dry. Its something I don't recall having noticed before. Its non slip. Its got a very thin rubbery coating on the back. I could have sworn it came from a 100ct box of wet or dry that is long gone. Only a half dozen sheets remain in a drawer with other various sand papers. |
#4
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Posted to rec.crafts.metalworking
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On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe"
wrote: I've got an old piece of granite counter top I glue wet or dry sand paper to with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. Yeah, not smooth. I wouldn't try to hone a plane blade on it. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. I'll take your word for it. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. http://www.supergrit.com/products/pr...ets-emeryflint googled. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. Additional question: Why do you have to wet-sand? -- The Road to Success...is always under construction. --anon |
#5
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On Mon, 30 Oct 2017 16:34:13 -0700, Larry Jaques
wrote: On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: I've got an old piece of granite counter top I glue wet or dry sand paper to with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. Yeah, not smooth. I wouldn't try to hone a plane blade on it. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. I'll take your word for it. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. http://www.supergrit.com/products/pr...ets-emeryflint googled. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. Additional question: Why do you have to wet-sand? Google "Double Drum Sander" https://www.ebay.com/sch/i.html?_fro...ander&_sacat=0 You can build your own easily. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#6
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Posted to rec.crafts.metalworking
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"Larry Jaques" wrote in message
... On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: I've got an old piece of granite counter top I glue wet or dry sand paper to with 3M spray on contact adhesive. Its great for rubbing a mold face on to remove burrs and to take out tooling marks on misc parts if I feel its worth the time. Sometimes to just make the mill rolled side of a part look better. Its not smooth, but its got a pretty good average flatness when checked with sunlight and a steel rule. I use it because I don't want to gunk up my surface plate with glue and abrasive grit. Even if my surface plate already has two chips and its only B rated. Yeah, not smooth. I wouldn't try to hone a plane blade on it. *** I have a regular granite surface also. Just don't want to do this on it routinely. I also sometimes use it with very coarse paper to level and take down an odd project. A recent one was a cutting down a plastic bucket. I sliced it on the bandsaw, and then squared up the cut end on my "sanding granite." It really works better than it sounds. I'll take your word for it. *** Thank you. I was surprised the first time I tried it. Slight Background Tangent: I use little rubber sanding blocks with 300 grit or higher to quickly knock down the burrs on a mold face before I use the tool height setter to set the next tool. (Sorry, no ATCs in my shop yet.) It works great. Better if the part is still dripping with coolant. However the wet or dry sand paper just doesn't hold up. Then one day I saw MSC had 3" wide emery cloth in bulk rolls. I bought a roll of 300grit and neither of my little blocks has had a piece of wet or dry on it since. When the emery is fresh I have to be really gentle, but it breaks in quickly enough to a much finer grit. At that stage it works for a few months before it wear through. The emery cloth roll is expensive, but in the long run it saves me money and a lot of time. The little ends under the flaps get tossed in the tool cart or tool drawer for one of the lathes. They don't see any wear so they are still nice little bits of full grit emery. Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. It would be nice to have some 100 grit for roughing on one end of the counter top piece, and some 600 or finer on the other end for polishing. http://www.supergrit.com/products/pr...ets-emeryflint googled. *** Thanks for the link I'll check them out. I don't like to finish fine with the rubber block as they can ever so slightly introduce an out of flat on flat surfaces. Just enough to knock the burrs flat, and move on. If it takes out the tool marks I sanded to hard. Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? *** It is, but I have a fair feel for the work I am doing. I'm no expert, but I get passable results and repeat customers. I would be deathly afraid of creating gouges or valleys with a drum sander. I sometimes use the flat platten of a belt sander for hard parts. You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. *** Yep. That was the core of my query. Finding emery cloth paper size sheets at fair prices. IT HOLDS UP. Some of the sources I've seen just say coarse, medium, fine. Even though the price may be ok I have to pass on those. I want to know the grit. Or atleast the grit I am starting with. Additional question: Why do you have to wet-sand? *** The paper doesn't clog up. I am sanding mostly aluminum. It clogs dry paper pretty fast. Its also why I hand dress molds between tool changes. I do not want to significantly change any dimensions. I just want to knock off the burrs before I place the tool height setter on the mold plate. If I ran an ATC or even ATC spindles that used tool holders I could use a tool height table and only have to dress the mold once at the end of the job, but alas this is a self paying hobby that turned into a business. Every tool pays for the next one. Decent ATC spindles cost. I'll have them sooner or later, but for now I am still making parts. -- The Road to Success...is always under construction. --anon |
#7
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On Tue, 31 Oct 2017 10:06:03 -0700, "Bob La Londe"
wrote: "Larry Jaques" wrote in message .. . On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? *** It is, but I have a fair feel for the work I am doing. I'm no expert, but I get passable results and repeat customers. I would be deathly afraid of creating gouges or valleys with a drum sander. I sometimes use the flat platten of a belt sander for hard parts. I'd think the platen would be as likely to score as a drum sander. You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. *** Yep. That was the core of my query. Finding emery cloth paper size sheets at fair prices. IT HOLDS UP. Some of the sources I've seen just say coarse, medium, fine. Even though the price may be ok I have to pass on those. I want to know the grit. Or atleast the grit I am starting with. Often, you have to ask the mfgr, and sometimes they have to ask their engineering dept for the micron or grit size. I use 6" x 2" diamond hones for the most part. $30 for a once-a-lifetime purchase isn't bad. I wonder how a DMT would work for you. Apparently, diamond hones are used to hone aluminum bores (unlined--gasp!) in engines. Additional question: Why do you have to wet-sand? *** The paper doesn't clog up. I am sanding mostly aluminum. It clogs dry paper pretty fast. Its also why I hand dress molds between tool changes. I do not want to significantly change any dimensions. I just want to knock off the burrs before I place the tool height setter on the mold plate. Yes, clogging is a nasty habit of abrasive papers. I doubt that stearates would make much difference with aluminum, but they do with wood dust on garnet paper. Emery sounds like your winning choice. If I ran an ATC or even ATC spindles that used tool holders I could use a tool height table and only have to dress the mold once at the end of the job, but alas this is a self paying hobby that turned into a business. Every tool pays for the next one. Decent ATC spindles cost. I'll have them sooner or later, but for now I am still making parts. You're going to CNC mill the surfaces? That seems a bit more serious than a hand-sanding for burrs. -- The Road to Success...is always under construction. --anon |
#8
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![]() "Larry Jaques" wrote in message news ![]() On Tue, 31 Oct 2017 10:06:03 -0700, "Bob La Londe" wrote: "Larry Jaques" wrote in message .. . On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? *** It is, but I have a fair feel for the work I am doing. I'm no expert, but I get passable results and repeat customers. I would be deathly afraid of creating gouges or valleys with a drum sander. I sometimes use the flat platten of a belt sander for hard parts. I'd think the platen would be as likely to score as a drum sander. *** the sandpaper might score the surface if I was using a coarse grit, but the platen is hard and flat. Again, its not for material removal. A single quick pass flat from end to end will clean up all the burrs. A round drum may leave a valley from its round shape if there is even a slight change in hand pressure as the work piece is passed over the drum. When I say harder parts I mean "harder" parts. Like 4140HT or... Not more difficult parts. Yes I do mostly low pressure aluminum molds, but I occasionally take other jobs. You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. *** Yep. That was the core of my query. Finding emery cloth paper size sheets at fair prices. IT HOLDS UP. Some of the sources I've seen just say coarse, medium, fine. Even though the price may be ok I have to pass on those. I want to know the grit. Or atleast the grit I am starting with. Often, you have to ask the mfgr, and sometimes they have to ask their engineering dept for the micron or grit size. I use 6" x 2" diamond hones for the most part. $30 for a once-a-lifetime purchase isn't bad. I wonder how a DMT would work for you. Apparently, diamond hones are used to hone aluminum bores (unlined--gasp!) in engines. *** Now that IS a great idea if I could afford diamond hones that are paper size or larger. When I do this I want to completely engage the entire surface of the plate. Again its not about material removal. Its about a quick clean up of the burrs and any really high tool marks. If I actually remove the tool marks I sanded to hard. (Usually) Additional question: Why do you have to wet-sand? *** The paper doesn't clog up. I am sanding mostly aluminum. It clogs dry paper pretty fast. Its also why I hand dress molds between tool changes. I do not want to significantly change any dimensions. I just want to knock off the burrs before I place the tool height setter on the mold plate. Yes, clogging is a nasty habit of abrasive papers. I doubt that stearates would make much difference with aluminum, but they do with wood dust on garnet paper. Emery sounds like your winning choice. *** I actually start learning how to do this several years ago, and only switched to this as my primary business last year. The first of this year I shut down my contracting company of 23 years to focus solely on this specialty niche of machining. Really only one market segment of the niche. If I ran an ATC or even ATC spindles that used tool holders I could use a tool height table and only have to dress the mold once at the end of the job, but alas this is a self paying hobby that turned into a business. Every tool pays for the next one. Decent ATC spindles cost. I'll have them sooner or later, but for now I am still making parts. You're going to CNC mill the surfaces? That seems a bit more serious than a hand-sanding for burrs. *** Often after milling a cavity there are small burrs around the edges. If I just threw a tool height setter on them the depth could be off (depending on the previous cutter and the aggressiveness of the cut) by a couple thousandths. If (for example) the next cut is an air vent of only ..002 to .003 then it might not cut at all, or not deep enough. A quick brush with a fine grit rubber block with little pressure removes those burrs and allows me to get a good next cut. I supposed I could tie up machine time chasing every edge with a tool, but its faster to do this in between measure by hand. Like I said if I had ATC spindles or atleast fixed height tool holders on my little high speed machines I could just dress the burrs once at the end of the job, but I don't so I found something that works with what I have. A final brush on the granite block sort of unifies the surface. *** Some of you may recall when I started down this path nearly ten years ago I asked for a lot of advise on this group about high speed small cutter machining in aluminum. I got some good advise, but a lot of it was not really specialized enough for what I was pushing for. Some of it was ok for very limited jobs, but not ok for jobs that took days. That was faster more efficient finished products. One person said, right here on this group, "You may be the only one here who is an expert at what you are trying to do." At first I took it as a slap in the face, because I was very much a neophyte seeking advise. Then I realized that what I am doing is not a major portion of machining as a whole. Many people here with decades more experience than me might not have the best answers for me and the goals I was trying to achieve. I would have to take the advise I could get, experiment, break tools, destroy machines, and make my own best compromises. For now, relatively cheap high speed spindles and a lot of hand finish work is the best compromise. As the work comes in the compromises shift more towards machinery investment with less hand finish work. P.S. I just quoted my biggest price ticket job ever (as a mold maker) yesterday. The customer said yes. They haven't sent me any money yet, but if they do I'll probably be upgrading atleast one of my machines to an ATC spindle unless I decide something else will give me a greater immediate gain in productivity. P.P.S Yes I have destroyed machines. Well maybe abused them to the point where I had to completely rebuild them might be more accurate. Thank goodness I started as a hack know nothing hobbiest repairing and rebuilding my own machines or they would have been "functionally" destroyed. P.P.P.S Yes, I had jobs that took days to machine. No those aren't Star Trek days. LOL. One mold I made early on took 30hrs of machine time PER SIDE. I slept on my shop floor with the machine running. The least little change in pitch woke me instantly. I had to cut it twice because I screwed up on design the first time. I spent a week in the shop to get that one done. A job like that would now take me only a few hours per side. That job was 1.3 million lines of code per side. I recently did a job that was over 5.6 million lines of code (2.3 per side). I ran the two halves on two machines simultaneously, and it came off the machines for hand finish work in just under 8 hrs. I'm not bragging. Or I'm not trying to anyway. Just trying to explain where I am coming from and how I got here. |
#9
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On Wed, 1 Nov 2017 09:54:42 -0700, "Bob La Londe"
wrote: "Larry Jaques" wrote in message news ![]() On Tue, 31 Oct 2017 10:06:03 -0700, "Bob La Londe" wrote: "Larry Jaques" wrote in message . .. On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? *** It is, but I have a fair feel for the work I am doing. I'm no expert, but I get passable results and repeat customers. I would be deathly afraid of creating gouges or valleys with a drum sander. I sometimes use the flat platten of a belt sander for hard parts. I'd think the platen would be as likely to score as a drum sander. *** the sandpaper might score the surface if I was using a coarse grit, but the platen is hard and flat. Again, its not for material removal. A single quick pass flat from end to end will clean up all the burrs. A round drum may leave a valley from its round shape if there is even a slight change in hand pressure as the work piece is passed over the drum. When I say harder parts I mean "harder" parts. Like 4140HT or... Not more difficult parts. Yes I do mostly low pressure aluminum molds, but I occasionally take other jobs. You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. *** Yep. That was the core of my query. Finding emery cloth paper size sheets at fair prices. IT HOLDS UP. Some of the sources I've seen just say coarse, medium, fine. Even though the price may be ok I have to pass on those. I want to know the grit. Or atleast the grit I am starting with. Often, you have to ask the mfgr, and sometimes they have to ask their engineering dept for the micron or grit size. I use 6" x 2" diamond hones for the most part. $30 for a once-a-lifetime purchase isn't bad. I wonder how a DMT would work for you. Apparently, diamond hones are used to hone aluminum bores (unlined--gasp!) in engines. *** Now that IS a great idea if I could afford diamond hones that are paper size or larger. When I do this I want to completely engage the entire surface of the plate. Again its not about material removal. Its about a quick clean up of the burrs and any really high tool marks. If I actually remove the tool marks I sanded to hard. (Usually) Additional question: Why do you have to wet-sand? *** The paper doesn't clog up. I am sanding mostly aluminum. It clogs dry paper pretty fast. Its also why I hand dress molds between tool changes. I do not want to significantly change any dimensions. I just want to knock off the burrs before I place the tool height setter on the mold plate. Yes, clogging is a nasty habit of abrasive papers. I doubt that stearates would make much difference with aluminum, but they do with wood dust on garnet paper. Emery sounds like your winning choice. *** I actually start learning how to do this several years ago, and only switched to this as my primary business last year. The first of this year I shut down my contracting company of 23 years to focus solely on this specialty niche of machining. Really only one market segment of the niche. If I ran an ATC or even ATC spindles that used tool holders I could use a tool height table and only have to dress the mold once at the end of the job, but alas this is a self paying hobby that turned into a business. Every tool pays for the next one. Decent ATC spindles cost. I'll have them sooner or later, but for now I am still making parts. You're going to CNC mill the surfaces? That seems a bit more serious than a hand-sanding for burrs. *** Often after milling a cavity there are small burrs around the edges. If I just threw a tool height setter on them the depth could be off (depending on the previous cutter and the aggressiveness of the cut) by a couple thousandths. If (for example) the next cut is an air vent of only .002 to .003 then it might not cut at all, or not deep enough. A quick brush with a fine grit rubber block with little pressure removes those burrs and allows me to get a good next cut. I supposed I could tie up machine time chasing every edge with a tool, but its faster to do this in between measure by hand. Like I said if I had ATC spindles or atleast fixed height tool holders on my little high speed machines I could just dress the burrs once at the end of the job, but I don't so I found something that works with what I have. A final brush on the granite block sort of unifies the surface. *** Some of you may recall when I started down this path nearly ten years ago I asked for a lot of advise on this group about high speed small cutter machining in aluminum. I got some good advise, but a lot of it was not really specialized enough for what I was pushing for. Some of it was ok for very limited jobs, but not ok for jobs that took days. That was faster more efficient finished products. One person said, right here on this group, "You may be the only one here who is an expert at what you are trying to do." At first I took it as a slap in the face, because I was very much a neophyte seeking advise. Then I realized that what I am doing is not a major portion of machining as a whole. Many people here with decades more experience than me might not have the best answers for me and the goals I was trying to achieve. I would have to take the advise I could get, experiment, break tools, destroy machines, and make my own best compromises. For now, relatively cheap high speed spindles and a lot of hand finish work is the best compromise. As the work comes in the compromises shift more towards machinery investment with less hand finish work. P.S. I just quoted my biggest price ticket job ever (as a mold maker) yesterday. The customer said yes. They haven't sent me any money yet, but if they do I'll probably be upgrading atleast one of my machines to an ATC spindle unless I decide something else will give me a greater immediate gain in productivity. P.P.S Yes I have destroyed machines. Well maybe abused them to the point where I had to completely rebuild them might be more accurate. Thank goodness I started as a hack know nothing hobbiest repairing and rebuilding my own machines or they would have been "functionally" destroyed. P.P.P.S Yes, I had jobs that took days to machine. No those aren't Star Trek days. LOL. One mold I made early on took 30hrs of machine time PER SIDE. I slept on my shop floor with the machine running. The least little change in pitch woke me instantly. I had to cut it twice because I screwed up on design the first time. I spent a week in the shop to get that one done. A job like that would now take me only a few hours per side. That job was 1.3 million lines of code per side. I recently did a job that was over 5.6 million lines of code (2.3 per side). I ran the two halves on two machines simultaneously, and it came off the machines for hand finish work in just under 8 hrs. I'm not bragging. Or I'm not trying to anyway. Just trying to explain where I am coming from and how I got here. Greetings Bob, You can get diamond abrasive sheets in pretty coarse grits. ebay has some 200 x 300, which is about 8" x 12", for $115.00 per sheet. I dunno if that's worth it for your stuff. see the link: https://www.ebay.com/itm/Insung-Diam...AOSwpDdVN1N e If you were doing lots of hard stuff that cuts slow with regular abrasives then maybe it would be worth it. Some diamond cuts very fast and some doesn't. It apparently depends on how the grit is made and the source, natural or man made. And the grit concentration of course. I have been using diamond lapping discs made for jewelry and lapidary work for grinding (mostly) carbide tools. They are way less expensive than ones made for metalworking. Some discs didn't keep cutting fast while others last and last. I don't remember who I got my last discs from but they have lasted for at least 5 years. I just bought a bunch from eBay and I hope thay last as long as my last ones. Eric |
#10
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Posted to rec.crafts.metalworking
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On Wed, 1 Nov 2017 09:54:42 -0700, "Bob La Londe"
wrote: "Larry Jaques" wrote in message news ![]() On Tue, 31 Oct 2017 10:06:03 -0700, "Bob La Londe" wrote: "Larry Jaques" wrote in message . .. On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe" wrote: Sanding by hand is an art. Have you considered a DIY or purchased wide drum sander? *** It is, but I have a fair feel for the work I am doing. I'm no expert, but I get passable results and repeat customers. I would be deathly afraid of creating gouges or valleys with a drum sander. I sometimes use the flat platten of a belt sander for hard parts. I'd think the platen would be as likely to score as a drum sander. *** the sandpaper might score the surface if I was using a coarse grit, but the platen is hard and flat. Again, its not for material removal. A single quick pass flat from end to end will clean up all the burrs. A round drum may leave a valley from its round shape if there is even a slight change in hand pressure as the work piece is passed over the drum. When I say harder parts I mean "harder" parts. Like 4140HT or... Not more difficult parts. Yes I do mostly low pressure aluminum molds, but I occasionally take other jobs. You could build it to fit your largest mold and then it could ostensibly handle anything that size or smaller. https://www.pinterest.com/brad2179/d...ander/?lp=true You could use emery instead of garnet paper. *** Yep. That was the core of my query. Finding emery cloth paper size sheets at fair prices. IT HOLDS UP. Some of the sources I've seen just say coarse, medium, fine. Even though the price may be ok I have to pass on those. I want to know the grit. Or atleast the grit I am starting with. Often, you have to ask the mfgr, and sometimes they have to ask their engineering dept for the micron or grit size. I use 6" x 2" diamond hones for the most part. $30 for a once-a-lifetime purchase isn't bad. I wonder how a DMT would work for you. Apparently, diamond hones are used to hone aluminum bores (unlined--gasp!) in engines. *** Now that IS a great idea if I could afford diamond hones that are paper size or larger. When I do this I want to completely engage the entire surface of the plate. Again its not about material removal. Its about a quick clean up of the burrs and any really high tool marks. If I actually remove the tool marks I sanded to hard. (Usually) If it's denibbing, wouldn't a narrower-but-long-enough strip do? 2x8 or 3x8, maybe? Additional question: Why do you have to wet-sand? *** The paper doesn't clog up. I am sanding mostly aluminum. It clogs dry paper pretty fast. Its also why I hand dress molds between tool changes. I do not want to significantly change any dimensions. I just want to knock off the burrs before I place the tool height setter on the mold plate. Yes, clogging is a nasty habit of abrasive papers. I doubt that stearates would make much difference with aluminum, but they do with wood dust on garnet paper. Emery sounds like your winning choice. *** I actually start learning how to do this several years ago, and only switched to this as my primary business last year. The first of this year I shut down my contracting company of 23 years to focus solely on this specialty niche of machining. Really only one market segment of the niche. Yeah, one tiny piece can keep a person busy. If I ran an ATC or even ATC spindles that used tool holders I could use a tool height table and only have to dress the mold once at the end of the job, but alas this is a self paying hobby that turned into a business. Every tool pays for the next one. Decent ATC spindles cost. I'll have them sooner or later, but for now I am still making parts. You're going to CNC mill the surfaces? That seems a bit more serious than a hand-sanding for burrs. *** Often after milling a cavity there are small burrs around the edges. If I just threw a tool height setter on them the depth could be off (depending on the previous cutter and the aggressiveness of the cut) by a couple thousandths. If (for example) the next cut is an air vent of only .002 to .003 then it might not cut at all, or not deep enough. A quick brush with a fine grit rubber block with little pressure removes those burrs and allows me to get a good next cut. I supposed I could tie up machine time chasing every edge with a tool, but its faster to do this in between measure by hand. Like I said if I had ATC spindles or atleast fixed height tool holders on my little high speed machines I could just dress the burrs once at the end of the job, but I don't so I found something that works with what I have. A final brush on the granite block sort of unifies the surface. A spare granite (broken tombstone), or your good surface plate? = ![]() *** Some of you may recall when I started down this path nearly ten years ago I asked for a lot of advise on this group about high speed small cutter machining in aluminum. I got some good advise, but a lot of it was not really specialized enough for what I was pushing for. Some of it was ok for very limited jobs, but not ok for jobs that took days. That was faster more efficient finished products. One person said, right here on this group, "You may be the only one here who is an expert at what you are trying to do." At first I took it as a slap in the face, because I was very much a neophyte seeking advise. Then I realized that what I am doing is not a major portion of machining as a whole. Many people here with decades more experience than me might not have the best answers for me and the goals I was trying to achieve. I would have to take the advise I could get, experiment, break tools, destroy machines, and make my own best compromises. For now, relatively cheap high speed spindles and a lot of hand finish work is the best compromise. As the work comes in the compromises shift more towards machinery investment with less hand finish work. P.S. I just quoted my biggest price ticket job ever (as a mold maker) yesterday. The customer said yes. They haven't sent me any money yet, but if they do I'll probably be upgrading atleast one of my machines to an ATC spindle unless I decide something else will give me a greater immediate gain in productivity. Congrats, if and when. P.P.S Yes I have destroyed machines. Well maybe abused them to the point where I had to completely rebuild them might be more accurate. Thank goodness I started as a hack know nothing hobbiest repairing and rebuilding my own machines or they would have been "functionally" destroyed. Abused or just flat wore out? Maybe a combo? And almost everyone starts out as a hack hobbyist. Time and experience temper that, if you keep your hand in long enough and frequently enough. I swear, I have to learn to TIG every time I turn the machine on. I just don't use it very often, and I haven't practiced as I should to really learn it well in the first place. That should change shortly, as I finish the harder of the items on the gazillion page project list now that I'm retired. P.P.P.S Yes, I had jobs that took days to machine. No those aren't Star Trek days. LOL. One mold I made early on took 30hrs of machine time PER SIDE. I slept on my shop floor with the machine running. The least little change in pitch woke me instantly. I had to cut it twice because I screwed up on design the first time. Oh, ouch! But at least it wasn't a crash from a screwed up line of code and you put a spinning mill bit through your chest. I spent a week in the shop to get that one done. A job like that would now take me only a few hours per side. That job was 1.3 million lines of code per side. I recently did a job that was over 5.6 million lines of code (2.3 per side). I ran the two halves on two machines simultaneously, and it came off the machines for hand finish work in just under 8 hrs. Perhaps I could ask you a couple questions once I get the Green Monster finished and start learning/writing G code. That's a healthy sized programming task. I'm not bragging. Or I'm not trying to anyway. Just trying to explain where I am coming from and how I got here. Cool, I get that. -- The Road to Success...is always under construction. --anon |
#11
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On Mon, 30 Oct 2017 14:01:19 -0700, "Bob La Londe"
wrote: Back to the point: What I want is to find some sheet size emery that is modestly affordable to use on my granite sanding block. I have the same issue with the wet or dry not really holding up very well when used wet. Sure its fine for a day, but the emery I use on the rubber blocks is good for months. I found some for sale somewhere once. Maybe MSC and I was absolutely floored by the price. This is where I buy my abrasives and have for at least a decade: http://www.barbkat.com/ --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
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