Replacing the control board
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Replacing the control board with or without replacing the motor. I like matching the control board the the motor. I found most control boards fail because either dust or pood design. Next is owner playing with board. Voltage spikes can be problem in some location but power strip with protection should work. I found yearly cleaning of boards exstens the life includes my mini lathe control board, welders , PC tower and my home's AC Please comment on your experiences with boards. {The DC motor have about 6 adjustments . Most mini lathes I seen only has 3 you can adjust 1. Low speed 2. High speed 3 . Max Torque. The rest are per set on board like 4. Torque acceleration 5. Breaking 6. Slope speed increase There some boards 6 adjustments 1. Low speed 2. High speed 3 . Max Torque. 4. Torque acceleration 5. Breaking 6. Slope speed increase There are are few more but almost never seen or better way not need a engineering going wild. The brushless has about same thing but a little different Like speed increases is slowly increasing the frequency. I know more but have had must do with brushless.} Dave
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davesmith1800
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Brushless mini lathe motor torque chart.
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Brushless mini lathe motor torque chart compare to DC motors. I know the DC motors have very high torque as the motor slow down. The standard ac squire cage motor is about same the rpm's drop off. But do not know what torque is on the Brushless electronic DC motors?. FYI Simple to compare the DC vs AC is. The old time heavy duty drill motors when star to slow you feel torque. AC motor like fan you stop it a small stick. Dave
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davesmith1800
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Mini lathe DC motor longevity
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Look at improve the longevity of the mini lathe motor. I see a lot members having motors problems. Now is from environmental , operator , motor control board or motor errors? FYI There are two basic type use on mini lathes DC motor and brushless aka {electronic 3 phase} motor. This only on the DC type. Please post how fix or you replace motor. Dave
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davesmith1800
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how to.inspect.motor?
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My.motor.is.behaving.badly. How.do. I inspect the motor? Do I just flip it on its side to get to the motor?
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Ralph Hulslander
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7x12 Motor Won't Turn On
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Had a crash awhile back while using a milling bit on my Grizzly 7x12 mini lathe. Motor stalled and fuse blew. I put in a new fuse, but motor won't run. Are there any other circuit breakers/fuses that could be the problem? Or, am I looking at a blown motor?
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Arthur Coe
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Off topic just FYI
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This just FYI. My temperature for this month was 79°F thank God for AC My mini lathe is a small shop without AC so have to other things. I only bring up heating because it can have a effect on your motors and you. I know some think humans are powerful. The last time I saw heat like this was 1972 when I was working as a iron worker. I did Iron work when I in high school and college. It paid for college and a nice machine shop tools. But outside in the heat. So if born after 1972 you think it is hot. You have to go back 1905 for hotter days. To cool off earth try a few big volcanos this lower to earth temperature by few degrees. I did not know if humans has any thing to do with the temperature increase is about all say on subject. I look pass Dave
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davesmith1800
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OT Hot Hot Hot
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And once the inside gets hot, it takes longer to cool it down, as the insulation keeps the heat in ralphie
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Jon Rus
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Double OT Hot Hot Hot
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Whole lot of “maybes” in that article. Also says the excess water will be up there for “maybe 10-15 years”, while if you read the actual paper is says “maybe 5-10 years”, so who know what orifice the reporter pulled those numbers from. Meanwhile CO2 hangs around for a 1000 years. Maybe people would take notice if we fired off a massive volcano every decade instead. Tony
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Tony Smith
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Hot Hot Hot
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I was wondering why fleeling Hot Check tv . No one is letting run my mini lathe.
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davesmith1800
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Group Guidelines
#guidelines-notice
TERMS OF USE -- How the 7x12 Group Operates The 7x12 Minilathe forum was founded as a way for machinists, both expert and novice, to help each other learn about our machines and to inspire each other to try new things. Here you can ask machining questions and expect to get knowledgeable answers. You can ask for help in finding just the right technique or design for a particular project. The files and archives can be searched for helpful hints and ideas to improve your knowledge and the quality of your work. In return we ask that you confine your discussions to machining related topics, that you treat each other as you would want to be treated, that you write your messages with a sense of camaraderie, and that you honor the rights of those who willingly give of their time by sharing their knowledge and ideas with you. Over time a group personality emerges, shaped by the people and personalities who comprise the group. We would like this group to be friendly and welcoming, a place where machinists of all skill levels come to teach and to learn and we ask your cooperation in meeting these goals. To help achieve those goals, the following rules govern operation of this group: * On-Topic posts only. Posts are not normally moderated, except those from relatively new members. But posts which are clearly off-topic will be deleted; the member's email status may be changed plus their posting status may be changed so their future messages are moderated. To avoid this, please refrain from responding to OT posts. Leave decisions as to whether a subject is OT to the moderators. Give them a little time to deal with the matter, and some latitude in judging what is off-topic. Experience has shown that some topics can drift into off-topic areas; for example, posts about using a lathe to make angling equipment can degenerate into fishing reminiscences and those about making car parts into the merits of member's past vehicles. Posts on making gun parts are a particular problem, as they can end up as general discussions about firearms and ballistics, or worse still as sterile arguments about the merits or demerits of gun control, where no-one is ever likely to persuade anyone else to change their views. Think before you post - is what you will be saying really on the subject of lathes and machining? * CNC, ELS and 3D Printer topics are handled in the https://groups.io/g/digitalhobbyist which is dedicated to these and similar topics. Or, https://groups.io/g/3D-Printing-for-Metal-Hobbyists * Please avoid religious or political asides or references in your messages, and likewise quotations, slogans etc at the end of them. Limit signatures to 2 lines maximum. * Be civil to your fellow members; derogatory or combatively worded posts will be deleted, and offenders placed on moderation. * Pictures: Following our move to Groups.io we would like to allow members to post pictures. We ask that only machining related pictures of lasting interest be posted. When appropriate include mention of the message number concerning the topic covered in the picture(s). Members who expect to post a number of pictures should make an album containing their name to hold their pictures. Pictures of passing interest should be posted in messages or on public servers like Flickr. * Files: Members may post machining related files. Again, these should be of lasting interest. * LINKS are found in the left menu of the Forum under Databases. Moderators may remove pictures or files judged not to meet the above stated criteria. Moderators are currently: John = GadgetBuilder = John@... Mike = DrMico60 Trevor = Trevor_Rymell Maximum size of pictures should be 800x600. Pictures may be cropped and/or resized using Irfanview (free) or any other photo processing program. One criterion for inclusion is that the photo should be of lasting interest, like a lathe modification or accessory, rather than something which will only be of interest while a question is being asked about it. This avoids "Photos" getting too cluttered with pictures relating to long-forgotten threads. *** Moderators
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Group Notification
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Mini lathe to make Painted Yahtzee
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There one use I use smalls a lot for painting. Need to cover badway and part lathe you do want dots on. Here simple project that makes a lot women happy back in 1995 the had Painted Yahtzee for the computer. They never made dice for this game. So can make your wife very with your lathe and nes 4 jaw chuck. On the mini lathe you can paint the dice the different colors. Wash off dice using rubbing alcohol. Use your 4 jaw self centering chuck and chuck up the dice for painting. It takes 5 colors using Testors 9146XT Promotional Enamel Paint. Note you buy purple or mix that color. Now just just use tool post to steady your and paint each color let dry between colors. Some dates you need to use white in dots to stand out. You only one on the block with Painted Yahtzee. I have included the paint chat , score pads and rules in PDF in the down load section. https://groups.io/g/7x12MiniLathe/files/99%29%20painted%20Yahtzee%20on%20mini%20lathe%20file I have used the lathe for a lot for painting Dave
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davesmith1800
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Vevor parts
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The Vevor 7x14 lathe I bought has no parts list and does not always match what is on other mini lathes. The quality of the parts has not always been the best. The keyway in the shaft for the "A" timing gear is not centered and does not allow the gear to go on without a lot of force. I need to prey it off with a screwdriver which takes a lot of one side/other side reps. The plastic timing gear are VERY tight on the shafts. The timing belt has 90 teeth rather then the standard 70. If I knew all of this before I bought it I would have passed on it. Has anyone else had any problems?
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paul mcclintic
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Large work holding
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I have a 6" x 1" round piece of aluminum that I need to turn into a flywheel for the model engine I am building. I was thinking of using superglue to secure it to my faceplate as it obviously does not fit in any of my chucks. Any suggestions how to hold this or should I go looking for someone with a bigger lathe. Dave Borneo
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David James
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Using the mini lathe
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My ok to polish the knives today as long not over 10 minutes. It also 98° in hobby shop at 10:30 today. This what used to polish the knives. Hope you put other uses for your mini lathe here for all to see. Still could not turn the plexiglass rod it take to long in 108° F day. Dave
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davesmith1800
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3-jaw largest bore?
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I seem to remember some years ago someone had increased the through-bore of the standard 3" 3-jaw chuck, but I can't remember where and didn't find anything in my search. It may have been toolsandmods.com, but that site appears to be defunct now. I was using the lathe last night and the 5/8" bar stock I was using had trouble sliding through the chuck bore. It was really tight. How big can you go without causing issues? I know the screws holding the back cover on are already close to the bore. Mike
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MikeK
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Project New type of material
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Just plexiglass rod for making game pieces from. First time turning plexiglass All my life has been metals. Any comments Dave
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davesmith1800
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Fixed steady rest
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I've been working on reducing the vibration in my Chinese 8" bench grinder. Adding collars for the inner wheel flanges to rest against and making new flanges (ala Harold Hall's "Tool and Cutter Sharpening"). I was cursing having only the 1" rest, when I re-found the steady rest mod doc in the Files section. Did not have a need for this mod until now. Putting the rest in the mini-mill vise, with the middle slot edge aligned with the left side of the vise, it was just some up and back on the Y to give me a nice opening for my grinder shaft to fit through. I wound up with a generous 0.885", and I could have gone even further, since I left about 1/32" on each side. Maybe one day I'll build a larger rest with a nice flip top like many of the Myford guys have. Mike
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MikeK
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speed control
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i've followed the thread about changing motors why do we not see reeves drives with a standard ac motor i think they're used on some wood lathes and larger mills i used to work on them for driving positive displacement pumps they're non-electronic and very simple
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fxkl47BF
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Motor swaps?
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It seems like the motor / speed control is a common issue with the 7" and 8" mini lathes, but I don't see many motor / speed control projects discussed. I follow several different small lathe forums as I find info for one is often useful for another. Motor swaps, are a common topic of discussion with other lathes from Unimats to 9x20. Am I just not noticing this here, or is this just not a popular mod with these lathes for some reason.
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Aaron Woods
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Lipstick on a pig?
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Some time back I started working on a DRO scheme for my lathe cross slide. There's not a lot of room on top so many of the approaches I saw had one disadvantage or another. As a result I came up with a scheme to put the DRO underneath the lathe and used a "C" shaped piece to transfer the cross slide motion beneath the lathe. I had an iGaging DRO for the purpose because I bought two when I was working on my Z axis DRO setup, so I already had what I needed. Or so I thought. Unfortunately, the iGaging design uses a sliding contact with a fairly strong spring, which required a fair amount of force to overcome. DRO mounting schemes that put the mounting system inline with the sensor aren't affected by this, but my C shaped piece would deflect under the force enough to cause about a .005" error. I tried several ways to stiffen up the system but that was about the best I could manage. So I decided to modify my DRO to reduce the amount of force needed to move the rule through the sensor. This involved making a replacement base out of aluminum and replacing the sliding contact with bearings. I used aluminum because the rule MUST be connected to the sensor's internal ground in order to work correctly. My first iteration used flanged bearings because the rule needed to be constrained on two of its axes, but the flanges rubbed on the rule too much, which caused erratic variations in the force needed to slide the rule back and forth. So I replaced the flanged bearings with conventional ones -- but then had to add bearings to the bottom and top assemblies to constrain the rule on its vertical axis. At this point I debated on whether it really was worthwhile to continue my attempt to use an iGaging DRO, but since I already had a fair amount of time invested in this thing I forged on. This is known as the "sunk cost" syndrome, and I admit to falling victim to it. So after buying more bearings and spending more machining time on the base (and 3D printing a cover, also with bearing pockets) I got this: The top photo shows the scale, sensor, aluminum base and printed cover. The side bearings are 3x10mm and the top/bottom are 3x6. And here are photos of the mounting scheme: I used a "T" extrusion in an attempt to stiffen up my "C" assembly but it didn't improve things much. The 3D printed stuff was done with an older Ender 3 I bought from a friend. This is the first project I've used it for. The pieces were designed using openSCAD. Not shown: all the pieces that had something wrong with them :). The scale passes through a slot I milled in the vertical piece. At first the (re) assembled DRO had a terrible EMI problem. I added some shielding on the back of the sensor board, which helped a teensy bit. It turns out that the main problem was the spacing between the bottom of the sensor board and scale. I had used some 3mm brass washers to make sure the board didn't rub against the scale, but that turned out to be a mistake. I removed them and suddenly the noise problem disappeared. The board still isn't rubbing so that was a solution without a problem. I was sure that the DRO would misbehave once it was installed and the motor controller was turned on, but so far so good. I checked the DRO vs the dial and they are very close. That was a big unknown, since I wasn't sure if the spacing between the scale and sensor board would affect the readings. Lipstick on a pig? Well, probably. If I had known what I was going to encounter along the way I think I would have just bit the bullet and found myself a DRO that would work right out of the box....
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Mark Kimball
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