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I got a Sieg SX2.7 (Little Machine Shop 5550) bench mill a few months ago and am looking to upgrade the end mills from the cheap set that came with it. I've picked out an assortment of Niagra Cutter 4-flute carbide TiAlN square end mills from MSC in 1/16", 1/8", 3/16", 1/4", 5/16", 3/8", and 1/2" diameters (series C430). Also looking at getting a 1/2" cobalt fine-pitch roughing mill and a 1/2" carbide 90 degree AlTiN drill mill for countersinking and chamfering. I don't know anything about brands of end mills and have no real experience with different coatings other than what I've read. Does this seem like a good assortment that would cover most needs for small projects in aluminum, brass, and steel? Aside from a fly cutter (which I already have) are there any glaring omissions to the list? Any thoughts on the brand or the coating? Thanks!
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Dec 29, 2019 11:41
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Thanks guys. That gives me a lot to go off of. I do have sets of HSS drill indexes in all four flavors, so I'm good there. Maybe as I break bits, I'll replace them with cobalt. The TiN HSS Interstate mills look exactly like the set I got from LMS. At almost triple the price, I'm hoping they're much better. I wrecked my 3/4" 4-flute mill taking a .020" pass on some high carbon steel. However, I was running at about 1000 rpm which is about 3x what my "feed and speed" app tells me I should have been at, so that was probably more my fault than the end mill. I slowed it down to about 350 rpm and did a 0.2" pass with an 11/16" 4-flute and it cut fine without damaging the end mill, but at that low of speed it was really causing the whole mill to vibrate (but not chatter). I have it bolted to a stand, but the stand isn't bolted to the floor. The stand isn't really that sturdy so I don't know that it would matter much if it was bolted to the floor. Higher RPMs to reduce vibration is one of the main reasons I was looking at carbide. I think I might still get a carbide roughing mill to reduce the vibration by running at much higher RPMs, then replace my other mills with the Interstate ones as I wreck them. Good to hear that a single flute countersink will work for chamfering. I hadn't thought of that, but I do have a couple uncoated HSS single flute countersinks, so that will save some money by eliminating the drill mill. I tried taking a small chamfer in that steel mentioned above and went okay, albeit slow and with vibration. I'll have to look up how to calculate the feed/speed for chamfers. As for the sizes of the end mills, 1/2", 3/8" and 1/4 seemed like good all around sizes for general work, 5/16" because that is what the blanks for my lathe are and I want to make more tool holders, and the smaller ones because they weren't that expensive. I don't have a slot cutter, so I figured they might come in handy.
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Dec 31, 2019 09:37
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When changing collets in a mill, is is best to crank the drawbar down tight, or just snug it?
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Aug 3, 2020 13:25
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CarForumPoster posted:This is one of those topics that really piss off machinists. I assume we're talking R8 collets in a Bridgeport style mill here. R8 collets in a LMS 5550 (SIEG SX2.7) benchtop mill. I was originally cranking it down pretty tight, but was worried that I might be going overboard. The last few months I've been going a little more than snug and haven't had any problems, but wanted to make sure it wasn't a safety risk.
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Aug 3, 2020 16:49
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A couple years ago, I got the ubiquitous Chinese mini-lathe (some variation of the SIEG C3 7x14 Mini Lathe). I purchased this quick change tool set and everything has been working as expected except the parting blade. It has a lip along one long edge (like a safety razor) that causes it to sit in the tool holder tipped at a bit of an angle along the Y axis like this /. If I try parting with it, the workpiece pushes the blade along the left-right X axis and it doesn't work worth a poo poo. I'm assuming the tool is designed and manufactured correctly, so I must be doing something wrong. Any idea what? Thanks!
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May 26, 2021 04:06
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echomadman posted:With all that mini late tooling its quite common to get parts that are not quite up to spec. Been a long weekend, so sorry for the delay. I checked the vertical orientation with a square and it seems to be completely vertical, so my guess is that my cross slide isn't square to the workpiece. Maybe a dumb question, but I do I have the parting tool installed correctly with the thick side on top (leading edge)?
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Jun 2, 2021 01:50
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ZincBoy posted:Thick end goes on top for sure. That tool also looks dull or has buildup on the top edge. Hard to tell from the picture. Yes, it is a bit dull and could use some sharpening, but I was having the same problems fresh out of the box. It's been a long time since I used the parting tool, but it is doing exactly what you describe by pulling into the work (towards the chuck) so I'll try sharpening it and shipping it up above the centerline and see how that goes. I'm pretty sure I checked the cross slide to make sure it was square to the work, but I'll check that again as well. I've been using in on brass and plastic mainly, but I do use lubricant when working aluminum.
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Jun 3, 2021 02:28
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echomadman posted:Ah, that's a T shaped parting tool, you might need to shim it on the lower section. Thanks for the link! I learned quite a bit from it. I assumed the tool holder was angled to compensate for the thicker edge of the T-shaped parting tool, but now I'm going to put it in my milling machine and check it with a dial indicator. If it isn't perpendicular to the base of the tool holder, I'll mill a relief to get it square.
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Jun 4, 2021 01:51
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ryanrs posted:I have some black oxide 18-8 stainless screws that feel nice. Does anyone know what coating this is? If I had to guess, I'd say it is black oxide.
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Jun 6, 2021 13:06
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Didn't This Old Tony make a wrench for turning two bolts at the same time?
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Jun 7, 2021 18:48
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Leperflesh posted:Can you not drop a line down the hole and then measure the line? You're re-inventing a sounding line, as used nautically. Is that like one of those strings that changes color every 10 feet? Maybe I'm just imagining that.
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Jul 8, 2021 14:18
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A while back, I had a jam and chooched the plastic drive gears in my chinese mini lathe from Grizzly. I replaced the gears with metal involute tooth gears and replaced the ball bearings with tapered roller bearings while I was at it. It is now much noisier than it was before. I disengaged the drive gears and spun the chuck with a drill and it ran quiet, so that tells me the bearings aren't making the noise which narrows it down to the gears. Is that just what is to be expected with metal gears, or does it sound like there is a problem with the tooth engagement or maybe I need some different grease?
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Apr 4, 2022 23:01
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Sagebrush posted:Heavy grease will quiet them down a bit. The engagement might be part of it but it's doubtful. If they're the same gear design, they're going to mesh the same way. I was kind of thinking if the spacing between the gears had increased, the teeth wouldn't be in constant engagement. I guess I can check that when I repack the grease. I get that metal gears are louder than plastic, but I'm wondering if it should be this much louder. I've ran it for several hours with no problems, but I'm half expecting to open up that gearbox and find a bunch of shiny glitter. Sagebrush posted:Something to consider: many lathes, and other machine tools, include a plastic gear or two specifically as an engineered-in weak point. In the event of a jam, the plastic gears strip out, but they're easy to replace -- and because they go first, they prevent damage from cascading to something more expensive. Now that you have strong gears in that location, the next time you jam the machine up, those forces are going to go somewhere else. I was very new and pushing it way harder than I should have been. I know better now. That doesn't eliminate the possibility of having another jam, but I'm feeling more confident now. I also saw a mod where you install an adjustable stop to prevent the tool holder from crashing into the chuck. That's great for hand-feeding, but I wonder what would happen if the half nuts are engaged.
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Apr 6, 2022 15:15
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Leperflesh posted:Have you driven a manual-gearbox car? Ever put it in reverse? That much, much louder sound in reverse is because the reverse gear is straight cut, while all the forward gears are helical. I have one and have owned several in the past. I guess I never put too much thought into why reverse sounded different, but that was an interesting video to watch. I may be able to get a video recorded and posted. It's kind of hard to judge sound from a video, so I was thinking of doing a comparison between the drill press, lathe, and mill so you'd have some reference points.
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Apr 6, 2022 17:53
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Enos Shenk posted:So has anyone ever done any machining with titanium? I'm not an expert machinist. I'm not even a good machinist, but I have worked with titanium. On my cheap chinese mini-lathe, I had to turn down a 9.5mm OD tube (I think it was 8.5mm ID) down to 9mm OD. I used aluminum cutting fluid because it was what I had handy and the surface finish was very nice, but I could not get it to break chips at all. It was a rats nest.
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Jul 7, 2022 03:18
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Just a quick ancedote of me being a dumbass in case it helps somebody down the road. I needed to mount a steel plate that was cut from an old Jeep bumper to an aluminum plate. It was four holes at the corners. The final result would be 5/16" through-holes fastened with 1/4-20 bolts with a washer on one side and a nut on the other. I had to keep everything aligned during the drilling with the drill press so the holes lined up, so I decided to thread and screw the first two holes to clamp the pieces together with the idea that I would drill the second two holes with a 5/16" drill and then remove the screws and drill the original threaded holes out with that 5/16" to give me four (eight) perfectly aligned holes. I drilled the first hole, tapped it to 1/4-20 through both pieces and ran a short screw through both pieces while they were clamped tight to hold it in place, the flipped it around to drill and tap the opposite corner. To keep everything accurate, I drilled the first two holes with a #7 bit, then removed the bit and chucked up a 1/4-20 tap while the parts were still clamped to the table, then manually turned the chuck while pulling down on the lever to tap the hole. Worked like a charm. To speed things up, I reversed the drill press motor and did a quick on-off flick of the switch to back the tap out. First two holes were drilled, tapped, and screwed and everything was rock solid. Decided to go straight at the last two holes with the 5/16" drill without any pilot holes and barely dented the steel. I was pushing hard, it was getting hot, and I was only seeing a bit of dust coming from the tip of the drill bit. Maybe my 5/16 was dull. I decided to step it down and drill a 1/8" pilot hole with a new drill bit. Same result. I thought maybe there was some reason that steel was a lot harder at that point and maybe I heat/work hardened it even more, so I switched to a 1/16" carbide end mill and it broke it in short order. I don't know poo poo about heat treating metal other than what I've watched on youtube, but I hand nothing to lose at this point so I put the two pieces in a vise and went at it with two propane torches with the thought that I could temper it back to something softer and more drillable. Because of the 3/16" aluminum backing plate still being attached and acting like a huge heat sink, that didn't seem to work very well, but I decided to press on and see if it did any good. I had a 12 pack of 1/8" drills, so I chucked up another brand new one and got the same results. I flipped the switch to turn the drill press off and grabbed the chuck to slow it down with my hand brake and that's when I realized it was turning counter-clockwise. After backing out the tap many steps ago, I forgot to flip the polarity switch on the drill press motor, so the drill press was rotating backwards during the whole frustrating ordeal. 
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Nov 9, 2022 04:32
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Leperflesh posted:I've done this more than once with a hand drill but it never occurred to me that I could run my drill press backward and set myself up for an even more expensive and frustrating experience, lol. I'm not sure if that is a normal feature on drill presses. Mine is a ~1970 Craftsman that I got from my dad about 20 years ago and I'm pretty sure the polarity switch is something he installed. Also, I think this was the first time in 20 years of owning it that I ever used that switch.
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Nov 10, 2022 18:51
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I'm way out of my league here, but would it work to pack the tube with sand (to keep it from buckling) and use a bender?
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Nov 20, 2022 22:33
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I was running my 7x14 Chinese mini lathe with my head up my rear end and had a crash which took a tooth away from one of the M1 Z80 gears that control the feed when the half nuts are engaged. I've checked McMaster, Little Machine Shop, and Grizzly and can't find a replacement. The closest thing I've found is this pair of 90(20)/80 gears that replace the existing 80(20)/80 gears. This will slow down the feed rate a bit, and I'm perfectly fine with that, but they cost $40. If I can find a direct replacement for $5 or so, I'd rather go that route. https://littlemachineshop.com/products/product_view.php?ProductID=1137&category=1 If I had a dividing head and a piece of round stock large enough, I might take a stab at making my own replacement gear, but I don't have those things. Another option I've considered that I do have the supplies for is using the non-broken gear to make a silicon mold and resin casting a replacement gear. I have some resin that is very imapact resistant, but I don't know how wear resistant it is. All that aside, anybody know where I can get an M1 Z80, 7mm thick with a 12mm bore 3mm keyed shaft gear for cheap? edit: I went ahead and ordered the gears from LMS. I'd still be interested in finding a source for cheap gears in case I break another one in the future. Skunkduster fucked around with this message at 14:26 on Dec 13, 2022 |
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Dec 13, 2022 01:17
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shame on an IGA posted:that is almost entirely a function of how long you want it to take and how much the time to stop the machine and replace worn tooling is worth to you. Something pedestrian like a 3/4" solid flute end mill, maybe $30-40 on the low end, something fancier like a indexable insert face mill that's wide enough to machine that whole surface in one pass you're looking at 6-1200 ish plus the inserts How much uptime on a CNC mill is practical for a 24/7 shop? I used to work in a print shop (as in printing things on paper) and I heard once expected average uptime of the equipment was about 66%. On that subject, we bought some huge printing press and they had to tear out the floor, dig out the dirt, and install a 6' thick concrete slab underneath to keep it stable. Are there similar requirements for larger machining equipment? I'm curious about EDM in particular. They are extremely high precision, but have very little rotational movement or vibration from what I have seen.
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Dec 14, 2022 02:45
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Yooper posted:If I had 66% uptime, it means I'm working on 1/3 of the equipment all the time and that would just be unsustainable. I suppose it is a different industry. That's why I was curious about it. We'd have jobs that could run 3-4 hours pushing 20-30K sheets of paper per hour with 100% uptime, then 15-20 jobs a day that would take 5-6 minutes setup for a 30 second run. Those little jobs bring bring down the averages. Running sheets of paper through a machine at high speeds is a delicate process. If humidity is up a couple percent, or if the reams of paper were cut from the middle of the roll at the manufacturer, it will introduce enough curl to cause the machines to jam every 30 seconds and take about 30 seconds to clear the jams and get it up and running. Jobs like that are what made me want to claw my eyes out. wesleywillis posted:Probably depends on how thick the floor slab is, what type of concrete was used, how much/how big the rebar is (or isn't) and whats underneath already. Would the climate also factor in? As in if the install was in a place with freeze/thaw cycles?
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Dec 14, 2022 04:05
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ante posted:Yo, I run all 3D printed change gears in my 7x14 Chinese mini lathe. They're totally fine for all my aluminum threading. I've crashed it, and the keyways strip out really nicely, saving the rest of the machine. It's a feature. What are you using for your 3D printer and design software? I have an original Elegoo Mars and am familiar enough with Blender that I could probably design and print gears, but I've found that the Mars is not dimensionally accurate on larger pieces. I'm guessing that is due to pulling forces stretching the print.
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Dec 23, 2022 21:04
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ante posted:OnShape and a Prusa i3. Any CAD software is fine, or if you like, I could just send you a set of STLs or my parametric gear generator file in OnShape. I'd appreciate it if you could email the stl files to myusername@gmail.com. They might come in handy down the road if I get a filament printer.
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Dec 24, 2022 02:20
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My job has me tapping an internal thread on a 304 stainless tube. The wall thickness is oversized, so that will allow me to drill it to the correct size for tapping. The tap is M6 .5mm pitch. I need to know what size pilot hole to drill, but all the tap charts I'm seeing only show M6x1mm and M6x.75mm. Any idea what drill I should use. I have fractional, metric, numbered, and lettered drills. Thanks!
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Jan 16, 2023 16:16
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shame on an IGA posted:https://www.machiningdoctor.com/calculators/threading/ Thanks for the quick reply! I don't think I will be able to find out the fit class as we're trying to fit a part from one manufacturer onto a part from a different manufacturer. Imagine installing an arrowhead from AAA onto a shaft from BBB. Luckily, the tube is much longer than we need, so if it doesn't work out, I can just part it off and try again.
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Jan 16, 2023 17:03
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tylertfb posted:Metric threads make figuring out the drill size very easy. Simply subtract the thread pitch from the thread major and you have it. For instance: M5 x 0.8 -> 5.0-0.8=4.2mm That is incredibly useful to know. Thanks!
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Jan 17, 2023 19:07
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Kaiser Schnitzel posted:I remember in college having to make a 15’ tall atom bomb that someone had to be able to sit on, had to be moveable by two people but couldn’t have wheels, had to be built in like 3 days, with budget of like $5. I asked a professor what the ‘right way’ to do that was and he said basically ‘well, probably nobody has ever had to make this exact thing before so there isn’t a ‘right way,’ you’ve just got to make one up.’ Don't leave us hanging. How did you do it?
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Mar 20, 2023 18:06
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I was just watching a video of a guy making V blocks out of some low carbon steel, then he case hardened them with charcoal and sodium carbonate in a forge. How deep does the carbon penetrate with this method? Is it just a couple thousandths with relatively soft steel below that?
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Apr 4, 2023 01:17
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Is 6061 aluminum or O1 tool steel (for example), going to be the exact same composition regardless of where you order it from, or do some foundries produce higher/lower qualities of material?
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Aug 31, 2023 18:59
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Yooper posted:Any reputable retailer (Not AliExpress/BangGood for example) is going to have the same poo poo. You can also request material certs. The only time I've ever seen a material related issue is when it comes from a 3rd world source, without certs, or traceability. Okay thanks. I don't do enough metalworking at this point for it to be an issue, but I was curious for future reference.
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Sep 1, 2023 02:26
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HolHorsejob posted:e: I need real advice. I want to make a flange-mount to foot-mount adapter for a motor. I've got a design worked up in solidworks, most of it's pretty straightforward, but the hard part is cutting a roughly 4.5" hole in hot-rolled steel to center on the motor's flange. How would you do this in a home shop? I don't have a torch or plasma cutter. Was considering this circle cutter in my drill press, though reviews are mixed. I wouldn't use a circle cutter. I used one to cut a couple 4" holes in a steel fire extinguisher enclosure. I don't know if it was case-hardening, work-hardening, or some other form of hardening, but it hardened that steel about halfway through the cut and would not continue to cut it. I don't know what that fire extinguisher enclosure was made of, so maybe your results would be different with hot-rolled.
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Sep 7, 2023 00:03
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Ambassadorofsodomy posted:I'm drilling a hole 40 feet deep today, 4 inch diameter. What size rivets should I use? Mmhmm.....make it a biggun'.
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Oct 12, 2023 18:21
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Leperflesh posted:Yes, you can weld with car batteries. It's the farmer's field weld special. You'll need to have flux of some kind, so stick welding is the best option. You want to weld DC- meaning you connect the positive to the part and put the stick in the negative. Why would it matter which way the current is flowing?
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Dec 5, 2023 04:38
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Thanks for the replies. I had never considered that the polarity would make a difference, but then again, my experience in welding is a 4 hour night course at the high school taught by a one of the HS teachers who I'm pretty sure also had zero welding experience.
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Dec 5, 2023 20:21
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Leperflesh posted:"I made a SUPER SHARP KNIFE from this CAST IRON PAN and then THIS HAPPENED" Most of the video consists of his wife beating his rear end for destroying her favorite cast iron skillet that has been passed down for generations.
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Feb 9, 2024 00:12
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My mill uses R8 collets, but I was thinking of getting some 5C collets with hex and square collet blocks and maybe an indexer down the line to do fluted shafts and knobs. I'm wondering if getting collets in increments of 16ths of an inch will be good enough. For example, if I am trying to hold a piece that is 17/64ths, would it fit in a 1/4" collet? If not, would it be too loose in a 5/16ths collet? My question is mostly academic as I'm just a hobbyist that turns and mills stuff for my own use, so I could most likely just turn whatever I plan to put in the collet to a multiple of 16ths and it would be just fine.
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Feb 18, 2024 17:38
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shame on an IGA posted:For the index head think real hard about what you would need to do with it that a lathe chuck couldn't handle I'm going to let my ignorance shine here and ask how do you index with a lathe chuck? I don't plan on making gears or precise splined shafts, so an indexing head is one of those "maybe some day" items that I might only use once every couple of years. In response to the other posts, I'm not dead set on 5C. If ER collets will work better, than I have no problems going that direction. I mainly want to be able to use square and hex collet blocks on the mill for situations where I make a round knob and I want to put some grooves in it for a better grip or maybe milling four or six faces on a turned object so I can get a wrench or socket on it. For handles, a knurling tool is another thing on my wish list.
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Feb 19, 2024 01:35
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Yooper posted:ER collets have the benefit of clamping on two surfaces (front of collet-back of collet. So as you lock it down it gives you better rigidity for the tool. We use a lot of 5C collets and in our experience you have a +0 / - 0.002" window for best behavior. We strictly buy Special Accuracy Hardinge and even then it's frustrating come inspection time. We do 100% inspection and regularly send them back. Sounds like ER is the way to go. I initially looked up hex/square R8 collet block holders and came up with nothing, but I did see quite a few hits for 5C so I assumed that was the alternative. Glad I checked here first. With a little bit of research, it seems that ER32 is fairly common and has compatible hex/square collet blocks and indexers. Keeping in mind that I'm a hobbyist with a mini lathe and benchtop mill in my basement and not a production shop, is there any reason going with ER32 would be a bad idea? Thanks!
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Feb 19, 2024 20:42
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CarForumPoster posted:New machine day! I have a mini lathe and found that Frank Hoose's videos are very helpful in learning how to use it and tune it up. https://www.youtube.com/@frankhoose/playlists Also, you'll probably want to upgrade that tool holder to a quick change tool post sooner rather than later. https://littlemachineshop.com/products/product_category.php?category=-419988835
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Feb 27, 2024 19:21
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CarForumPoster posted:It came with a quick change tool post... I'd love to see a picture of it if you get a chance.
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Feb 28, 2024 20:08
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