probably others) with screw on

2021/05/21

And probably others) with screw on chucks have dogs which hook behind the flange on the mandrel, do that the machine can be run in reverse without fear of the chuck unscrewing. So, I looked at the table and saw that a pitch of 1mm was one of the super-easy pitches. When cutting the external thread in the bar, the top slide needs to move in by 7/8 of the 1mm pitch (ie 0.875mm). Lay a rag across the ways or a little dab of grease helps. For quick and easy day-to-day threading gages, I keep a complete set of nuts on rings in my toolbox for fitting threads. Nearly as many types and forms of threads exist as there are products that use threaded fasteners and connections. I have always enjoyed cutting threads on the manual lathe and have learned a few tricks over the years. I have yet to try it in the rear tool post. On the last pass, feed straight in with the cross-feed at a light 0.001 " spring cut. Too easy to chip an edge and SFPM is less than optimum for carbide. When in doubt, just use the same number or line each time. Keep cutting until 15mm has been reached - disengage the half nuts, Wind the cross slide in to make sure the cutting tool clears the workpiece. Comes in a variety of forms, ranging from manual to semiautomatic to fully automatic, with major types being engine lathes, turning and contouring lathes, turret lathes and numerical-control lathes. __________________________________________________________________________________. A buddy of mine had an Enco mill, and was tearing the head apart to work on it. JavaScript is disabled. The details about using the numerator column are given in the final step. It can be done with a conventional HSS bit or if you use insert tooling and don't need ctr support then the internal threading tool makes it easy to reach around the back without having to move the topslide rearwards. So do I assume the chuck runs backward and the tool is upside down or is the tool mounted on the other side of the work piece. This will allow you to achieve a sharper cutting tool, thus a better finish. The use of the small spacer gear, and the position of the leadscrew spacer can be seen in the photos. This will help "cut" the threads instead of smashing/ forming them (like in a zero rake tool), especially in aluminum. Do internal threading from the inside out with left-hand tools. How Many Loads You Get Out of Your Brass. Every time I turn around I'm spending just another couple hundred on this dang hobbybetween lathe tooling and loading equipment I'm gonna go broke. Somewhere I read that you should leave the last normal pass a thou or so short, then do a final plunge cut with the cross slide, to leave a nice finish. I think the offset of 29.5 degrees forces you to cut on one side of the thread only??? For subscription issues please see THIS LINK. I wasn't allowed to clean out chips that was someone else's job? Of course only a dedicated follower of over-complication would know about that sort of thing. Another advantage to threading with the compound is you dont have to keep track of the dial position. See turning machine. Ignoring all the mathematics details. Problem is I forget two. I hope all of the above makes sense - sorry to be so wordy. Cutting the thread with the lead screw running in the opposite direction. Toolroom and bench lathes are used for precision work; the former for tool-and-die work and similar tasks, the latter for small workpieces (instruments, watches), normally without a power feed. By continuing to use this site, you agree to our use of cookies. The Instructable gives details about making a pair of internal/external metric threads in 1" (25mm) diameter aluminium tube/bar. However, the final job is nice and close-fitting so I think the basics are right?

I also watched his video and do threading just like he does(away from the carriage). If your lathe can't run backwards or you are worried about the chuck coming loose you really should fit a simple electrical stop switch to the motor that is pushed by the carriage. A precision instrument with a spindle moved by a finely threaded screw that is used for measuring thickness and short lengths. On a Myford ML10 with a metric leadscrew (like many lathes with metric leadscrews), some pitches are painful, because the thread indicator is virtually useless. At the end of the pass, you can disengage the half-nuts and wind the carriage back by hand. This bought the top face of the HSS tools to their correct place (just below the centre line of the lathe). I have not seen a 'Machinists Handbook', perhaps they have tables for virtually every diameter? Taper your DOC as you get deeper. Thank you Jason, a picture speaks etc, Bazle, my lathe can run in reverse and the chuck bolts to the spindle back plate, this would make thread cutting less panicky as I dont have split nuts and no thread dial. The cross-feed dial is always zeroed after each pass, so you have less to remember, such as whether the last pass was at 0.030 " or 0.050 ". To temper it, I wanted to judge the colour change with the tool starting from a high polish (I gather this is what you have to do - heat it up until the surface colour changes). Use the info in Step 3 to work out the dimensions you need. I often need to turn threads inside bores, to make adapters and rings/flanges. The column labelled "Numerator" is the key to this. I've yet to try thread cutting myself, but your explanations are very clear and I particularly like your comments about what was actually happening at each moment. As seen in his videos, I also find it much less stressful and have not had any issues with breaking carbide. My Boxford can easily part off in the conventional manner when using it. Another somewhat scarier tip is to do the thread with a faster spindle speed, usually your reactions are the limit, when you see a CNC doing a small screw thread it is actually quite horrifying! If you need more, let me know - I will try to get a photo to show the benefit of the 10 degree offset. if you thread on the inside and start on the close side, it applies down force to the lathe carriage and produces normal loads on the lathe tool and carriage. One ring holds coarse threads and the other holds fine ones. In external threading, a calculated depth is required as well as a particular angle to the cut. The Boxford had this as a standard accessory to protect the school lathes from careless children. All rights reserved. If the 4-way toolpost and tool are exactly at 90 degrees to the axis, and I try to drive the tool very close to the chuck, then the (oversized) toolpost can foul the chuck. If you must use the same material for male and female threads, do yourself a favor and put a few molecules of thread lubricant or antiseize on them before you crank them together. Well done. In general, I was not overjoyed with the quality of the finish. Many thanks for your comments. He means starting where you would normally stop the carriage. This does not affect the maths. Thinking out loudsingle point cut chambers? Pleas, Internal and External threading on HF 7 x 10, Need help with internal threading Nexus 250MYII. After much mental torture, I worked out what angle the HSS tool steel had to be held at, on the grinder, to create the desired shape. CTE. The shallower depth on difficult-to-cut materials might save your bacon. Edited By fishy-steve on 22/12/2018 17:31:31, Edited By fishy-steve on 22/12/2018 17:31:48. Watch the depth gauge go from a negative value, through 0mm and start thread cutting after 3mm. I did not really adjust the depth of cut much, but realise that I could have started with a deeper cut and then reduced it considerably as I got near the end of the job. I'm not sure what is the best practice for this. To make everything work, I have to do both rotations. The Amazon tools worked just fine, as expected for aluminum. Align your threading tool against a freshly faced end or against the side of the chuck. The top slide is angled by 29.5 degrees when cutting the threads, so that the tool only cuts on one of its edges (rather than plunging in). The leading edge of the cutting tool should be making the cut.

Due to this angle being parallel to the triangle's sides, the distances to move the top slide are related to the length of the triangle side (1mm in my case) and not to the height of the triangle (0.866mm) which was used in the other calculations above. It is hands and eye coordination and brain trying to keep everything in going correctly. Surely a LH insert may not have the correct clearances? Saves a lot of time for production work. I did not have to worry about the thread indicator for this chosen pitch of 1mm. This cuts on both tool flanks and removes chatter and tool marks from the thread. You can't rotate the tool holder on your lathe? Share it with us! If your tooling is sharp, this won't be a problem. Sometimes called primary relief. I used a parting tool to form the lead-in and lead-out areas. Some of the later Eastern lathes (examples are:Warco BH600, BH900, Chester craftsman, Engineers ToolRoom BL12 - 24. Looks like a real possibility for other machines?? I tried it today with a hss tool I ground and snapped off the tip like I've never done before. You will need left-hand threading tools, running the lathe in reverse. This is not true. Skip the rest of this step if you are bored by the maths - the next step does just the same, without any theory! My question is, is it possible to use an external RH lay down threading insert in a reverse threading LH holder for internal RH threading?

What ideas do the team have to lock the chuck onto the spindle nose when cutting in reverse or rear tool post parting off. I cut on the front side, because it allows use of the compound rest. I did this for so many years. If you buy a really cheap, plastic cooking spoon from a discount store, you end up with 30cm of polythene rod which is over 1cm in diameter. Thanks for your interest. When I want to do something with the groove that gets cut at the end of the thread, I usually use the threading tool and traverse a small relief at the end. Process of both external (e.g., thread milling) and internal (e.g., tapping, thread milling) cutting, turning and rolling of threads into particular material. As you "hone" your threading skills you will get more comfortable and familiar with how your lathe reacts to the tools that you present and eventually you can worry about the smaller things like thread measuring and centricity. I heated it up to cherry-red and dunked it in water - no problem. I don't know what a typical number of honing strokes people use (1, 5, 10, 20???). For a better experience, please enable JavaScript in your browser before proceeding. If you only have a mains on off control get a sealed switch. To help the fitting, I parted off the 3mm relief cut from the start of the internal thread - and with it, the poor thread-start which the half-nut errors caused. this is a turning between centres workpiece. Still have a set of gauge blocks ($20) I use for less demanding work, hardened 1-2-3 blocks (reground by me), and a few other items. 8 years ago Then: Keep going until the calculated depth of cut has been reached on the top slide - this should coincide with touching the 'bottom' in the first 3mm of the tube. Enco was the Harbor Freight of machine tools. This is from the "Myford ML10 and Speed 10 Lathes notes on Installation Operation Maintenance" (Booklet number 743L). Machinery Manual, Brochure / Photo Archives, SolidCAM for SolidWorks and SolidCAM for Inventor, Mechanical Calculations/Engineering Design, Mass finishing equipment/media/strategies, 80/20 TSLOTS / Other Aluminum Framing Systems, General CNC Plasma / Oxy Fuel Cutting Machines, Plasma, EDM / Other similar machine Project Log, General Laser Engraving / Cutting Machine Discussion, Laser CO2 Tubes, Diodes, RF and Power Supplies, Printing, Scanners, Vinyl cutting and Plotters, Commercial Products / Manufacturers Support Forums, General CNC (Mill / Lathe) Control Software (NC), Additive Manufacturing / 3D Printers and 3D Scanners, General 3D Printer / 3D Scanner Discussion, Musical Instrument Design and Construction, Education - Forum for Technicians and Engineers, CNCzone.com-CNC Machines, CadCam ,Classifieds, Metalworking,Woodworking, If this is your first visit, be sure to As Dave suggested, regardless of the rotation of the spindle, or the side on which the tool cuts (front or rear of the part), the side on which the angle of the compound is set is always determined by the direction of the carriage movement during the cut. I used an adapted digital tyre gauge (magnetic attachment) which made the job easy - especially as the dimensions were not critical: First I adjusted the angle of the top slide to 29.5 degrees (see photo) and mounted the threading tool (inserted into its bar) at the correct angle to get a symmetrical thread shape. Best wishes and thanks for the advice on lubrication, etc. Relief on end teeth is axial relief; relief on side teeth is peripheral relief. On the Boxford, there is a rear saddle clamp, and a front saddle/ bed lock, but its a fiddle trying to tighten the rear cap screws when they are inverted and out of sight. I decided to cut a thread with a diameter of M23.6 and a pitch of 1mm. This is why I chose 1mm pitch. In theory, a specific HSS cutting tool would be made for each thread pitch to achieve the proper profile - both my internal and external cutting tools were as sharp as I could make them, so the 60 degree angle went right to the bottom of the threads.