Contributing Member JLSleather Posted February 7, 2016 Contributing Member Report Posted February 7, 2016 Yeah, IF I had that lathe i mentioned not having I'd likely go with a simple piece of 6061 aluminum about 1" dia. The stuff is cheap, polishes to an insane mirror finish, doesn't rust (or stain leather), and 1" is enough to keep the 'flex' out of it, without creating a 9 million sfpm speed (remember that the 1.5" is moving 1.5 times faster at the same RPM) Quote "Observation is 9/10 of the law." IF what you do is something that ANYBODY can do, then don't be surprised when ANYBODY does.
Members TinkerTailor Posted February 7, 2016 Members Report Posted February 7, 2016 One thing to consider is the nature of a metal lathe. It is not nearly as easy to make the radius at the bottom of the slots, unlike a wood lathe. Standard toolbits need to be moved in the x and y axis at the same time to make the curve. This is not easy for even an advanced machinist. The other ways to do it are either with a tracer attachment to the lathe which require an accurate pattern of the end parts profile for the lathe to follow or by using specially shaped forming tools to make the grooves. These tools would likely be job specific and/or custom ground. What this means is there is a significant amount more prep, setup, skill and possibly custom tooling involved in making the grooves on a metal lathe. This makes it cost more. Almost any monkey can gouge some grooves into a wood dowel on a wood lathe. Quote "If nobody shares what they know, we will eventually all know nothing." "There is no adventure in letting fear and common sense be your guide"
Contributing Member JLSleather Posted February 7, 2016 Contributing Member Report Posted February 7, 2016 (edited) Back when I did lathe work consistently, we had programs for the cnc which could turn about any radius larger than 1/32" (internal) and we had form tools which made radii from about 1/8" up to 5/16". "Dig" it out with a "normal" tool, then 'plunge' the form tool.... done If I ever get caught up on stuff, I'm not opposed to getting a small benchtop cnc lathe that would make things like this while I pound leather Edited February 7, 2016 by JLSleather Quote "Observation is 9/10 of the law." IF what you do is something that ANYBODY can do, then don't be surprised when ANYBODY does.
Members Ole South Posted February 8, 2016 Members Report Posted February 8, 2016 Okay, since machining one of these lil guys seems out of the question... I went looking around. I found, Bobbin drive wheel from old domestic Singers (99k, model 66 etc)... Pull the tire off an you've got a 5/8ths (bottom of race) steel pulley mounted on a 1/4 shaft with a race of about a 3/32nds radius. You might find an aluminum drive wheel from a late 50's 221 Featherweight. Same assembly from a Patcher bobbin drive... These look to be closer to 7/8ths bottom of race diameter and a slightly wider radius.. Options: Tear apart an old 3 1/2" hard drive. The spindle in these are 1" diameter aluminum; probably similar to aircraft grade. You'll have to find one that doesn't have a live center, some have bearings mounted where you need to put the shaft. Too bad the the motors don't have enough uumph or you'd have your burnisher and motor right there. You'll still need to cut a groove, but a little time with a round file and abrasive paper will get you there. The wall thickness and workable height of the spindles vary. Older drives stacked more platters, thus were taller and usually had thicker walls. You will have to cut or break these free of the motor as they are pressed on. I have used the entire motor/spindle assembly as light duty live centers on drill press and (yes Tinker, gawd FO-bid...) my lathe. Quote
Members charlescrawford Posted February 8, 2016 Author Members Report Posted February 8, 2016 Sweet thanks for the info! I will see what I can find! Quote
Members Tigdim Posted February 11, 2016 Members Report Posted February 11, 2016 (edited) I am new to leather work and was going to post up some questions about the powered burnishers being discuses in this thread. Figured, I would ask here rather than start a new thread. Background: I am a Mechanical Engineer and I have access to a machine shop. I plan to make one of the AL edge burnishers like in the Sam Andrews video for a drill press. Unfortunately, per company policy, I can't use the CNC equipment unless I get sent out for training. (which my boss does not plan to do any time soon... grumble grumble) My plan is to use the manual lathe to cut the slots getting close-ish to the radius... Then taking some wood lath of the desired thicknesses and radii (with radius edges cut on router table) and sandpaper to finish off the radius while still in the Lathe. Questions: What width slots do you think are appropriate? What radii should I use at the bottom of the slots? Aaron Edited to add PDF AL Burnisher for Drill press.PDF Edited February 11, 2016 by Tigdim Quote
Members charlescrawford Posted February 12, 2016 Author Members Report Posted February 12, 2016 I know the widest channel I would like to be close to 3/4". If you get something that works let me know and I will get you to do one for me! Quote
Contributing Member JLSleather Posted February 12, 2016 Contributing Member Report Posted February 12, 2016 That's one right purdy drawin' ya got there I would think that you'd want a full radius up to about 1/4", and larger than that, the 1/8" radius should be fine. Sketchin' shortly ... Quote "Observation is 9/10 of the law." IF what you do is something that ANYBODY can do, then don't be surprised when ANYBODY does.
Members TinkerTailor Posted February 12, 2016 Members Report Posted February 12, 2016 (edited) 'Tis a nice drawing for sure. If you are going to do it on a lathe manually, 2 things i can suggest: Grind an hss tool to the radius of the bottoms of the slot, and switch to it when close to final dimension. Its probably going to be necessary to cut the grooves with a parting tool, to get the depth and straight sides,as drawn, and switch to a shaped cutter for the bottom. Radius the outside corners on the slots too. If you tip the leather while burnishing the square edge makes a line on the front. It will also make it easier to insert the leather. If you are making more that a couple, look up how to make a diy tracer setup for a manual lathe. It will make things way faster. You will need a waterjet/laser/plasmacam/handfiled piece of metal with the final profile of the burnisher to do this. You basically have the profile attached to the lathe bed in some way or another with the profile facing the toolpost parallel to the work. I have seen them clamped to the side of the tailstock for eg. You will also need a second dummy follower tool attached to the compound bed. This tool follows the pattern as you run the wheels, while the other cuts. The cutting tool is fed in with the compound slide for each pass, and you just steer the dummy tool as close to the pattern as you can with the x and y. Follow the pattern, dial in a few thou more and follow it again. If you pattern it undersize, you can use a smaller width tool to get it started, and then switch to a wider form tool to widen the slots and add the radius for your finish cuts. If the width of the forming cutter is accounted for in relation to the distance you have narrowed the slots, it should turn out correct. Think of a key cutting machine. Edited February 12, 2016 by TinkerTailor Quote "If nobody shares what they know, we will eventually all know nothing." "There is no adventure in letting fear and common sense be your guide"
Contributing Member JLSleather Posted February 12, 2016 Contributing Member Report Posted February 12, 2016 (edited) This might work. Honestly, I'd ream a hole and insert a steel shank ... aluminum in a chuck never a great plan Done like this, chunk of al is about 1 1/4" x 4 1/2" if you have an inserted shank. Second timeza charm Edited February 12, 2016 by JLSleather Quote "Observation is 9/10 of the law." IF what you do is something that ANYBODY can do, then don't be surprised when ANYBODY does.
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