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Re: Mini-lathe Z-axis backlash
#LATHES
That's great, Charlie! Glad I could be of some assistance. One of these days, you might want to put some of the low-strength loc-tite in there. Next time you have to do this, not now. If it ain't broke, don't fix it! ;) Bill in OKC William R. Meyers, MSgt, USAF(Ret.) A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 01:18:29 PM CST, CLevinski <clevinski@...> wrote:
Bill, My lathe (a Real Bull) has two half-nuts. I removed the lead screw covers, and was able to determine that the issue was the three small adjustment screws as seen on the far right of the apron below. These were all loose. Readjusting them got the backlash down to 0.0015 inches! Thanks to you and Jonathan for your replies... -- Regards, Charlie New Jersey, USA ? ANTHONY¡¯S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop. THE LINDO COROLLARY: If you have cats, they will promptly hide the tool. |
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Re: Mini-lathe Z-axis backlash
#LATHES
Bill,
My lathe (a Real Bull) has two half-nuts. I removed the lead screw covers, and was able to determine that the issue was the three small adjustment screws as seen on the far right of the apron below. These were all loose. Readjusting them got the backlash down to 0.0015 inches! Thanks to you and Jonathan for your replies... -- Regards, Charlie New Jersey, USA ? ANTHONY¡¯S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop. THE LINDO COROLLARY: If you have cats, they will promptly hide the tool. |
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Re: Mini-lathe Z-axis backlash
#LATHES
Charlie, do you have the two half-nuts, or a single half-nut and retainer like mine has? A worn out half-nut or half-nuts, or loose screws on the retainer or half-nut(s), the shaft(s) in the groove cam, or the channels in the groove cam itself could be worn. Might also check to see that the rack screws are all tight, and the rack is not worn. Can't get rid of all of the backlash, but should be able to reduce it. Yours gets a lot of use, so it could have only one problem, or several. There are probably other things I didn't think of. I was just looking at the carriage portion of the parts diagram for my HF 7x10 model 93212. Yours could be wildly different from mine, as mine is strictly stock in that area.? HTH! Bill in OKC William R. Meyers, MSgt, USAF(Ret.) A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. LAZARUS LONG (Robert A. Heinlein)
On Wednesday, November 11, 2020, 11:11:39 AM CST, CLevinski <clevinski@...> wrote:
Hello, All, I am having an issue with my mini-lathe, in that it seems to have excessive backlash in the Z-axis. (I.E., from the leadscrew to the carriage.) Backlash seems to be about 1.00 mm / .040 inches, which seems like a LOT as my Z-axis pitch is 0.0625 inches You may be thinking that this doesn't matter, and it doesn't if you use change gears, as long as you move your threading tool beyond the end of the part being threaded by at least this Z-axis backlash. But if you are using any kind of Z-axis digital control, it is an issue. I probably have a mechanical problem, for which I will now look, but this made me wonder: what IS the typical Z-axis backlash on a mini-lathe? If any of you have measured it, or can measure it easily, I'd appreciate your replying with your findings. Many thanks! -- Regards, Charlie New Jersey, USA ? ANTHONY¡¯S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop. THE LINDO COROLLARY: If you have cats, they will promptly hide the tool. |
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Re: What did you do in your shop today?
#MISC
Wheel,? do you mean the aluminum ring with the jog bored holes. ? I use this ring that is bolted to the back spindle flange of my 7 x lathe chucks/Er 32 collet holder With ?a spring?loaded indent plunger attached to the headstock?end of the lathe entering into the holes. This allows for accurate indexing of the chuck. So if for instance you wanted to slot a multi internal spline. Bored holes spaced at 15 degrees apart. the chuck spindle is locked during cutting/slotting using the power feed Z axis ELS/RELS. Comparing angular?displacement to the RELS display, pretty well on the money.? Boring head is a Wholhaupter. (German) it bores and faces, including stops if you wanted to cut in a circlip or "o" ring groove, internal or external. I was lucky to find a used complete box and selection of goodies for my #2 MT mill spindle including DIXI Swiss boring tools, for about $500. One of the best tools I have bought.? Sometimes heads are available second hand in the dreaded R8 taper, but not this side of the pond. CNC ISO 40 or 50??tapers are very common. see typical John On Fri, 30 Oct 2020 at 13:17, CLevinski <clevinski@...> wrote: John, --
John |
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Re: What did you do in your shop today?
#MISC
Richard
¿ªÔÆÌåÓýIt may be inexpensive to you, but to us Brits that is a fortune!?We have to "make do and mend". That is why I built this. Gear was ex lathe change-wheel set and all material came from local scrapyard. I probably bought the screws at some time (when I was flush with money)! Richard On 28/10/2020 22:16, CLevinski wrote:
Hi, Ralph, |
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Re: What did you do in your shop today?
#MISC
Use of circular tables.
Most dividing plates will fit on a circular table. reasonably priced from Arc Euro Trade UK. 4" tilting head to 90 degree table also Arc Euro. Photo 1 shows a typical dividing/indexing plate installation. I needed to do some modifications to fit the plates onto the 4" circ table handwheel arrangement, but maybe the newer model tables have bolt staright on arrangements. certainly my 6" circ table was plug and play. The 4" table Charlie shown in his excellent photos is the standard degree hand wheel and agree what he was machining did not need? dividing or indexing. Dividing or Indexing head no fraction spacings should not be confused with angular dispalcement. Degrees min secs. Circular tables are normally 40:1 72:1 or 90:1 ratio. for a complete 360 degree movement. IE 72:1 ration, means 36 full turns will move the table 180 degrees. Commercial bought indexing plates normally are 4 in a set with holes ranging from 15 thru 65. I have attached a spreadsheet for 72:1 ratio plate and part turn selections. For 40:1 , 90:1 ratio circular tables just read the SS instructions on the RH side and alter, then save under a new file name. File cells should not be locked . Hope this helps -- John |
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Re: What did you do in your shop today?
#MISC
That does not look like a cheap dividing head. Ralph On Wed, Oct 28, 2020 at 2:39 PM John Lindo <bechetboat@...> wrote:
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Clausing 8520, Craftsman 12x36 Lathe, 4x12 mini lathe, 14" Delta drill press, 40 watt laser, Consew brushless DC motors and a non working 3D printer |
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Re: What did you do in your shop today?
#MISC
Nice solution and well set up on the dividing head. Well done. Thanks John On Wed, 28 Oct 2020 at 19:36, CLevinski <clevinski@...> wrote: Hello, All, --
John |
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What did you do in your shop today?
#MISC
Hello, All,
Since I think many of us are stuck at home due to quarantines and other restrictions, this might be a good time to revive this subject. Unfortunately, I haven't been in my shop all October due to some personal matters, but those are finally over. The last thing I was working on was a PC board holder that would allow the board to be rotated quickly to work on either the component or solder side. The base you see here is a casting off of an old drill press. The two blocks have slotted holes that allow movement and are locked with a bolt. You can see the only portion that I purchased in the background. These long arms are slotted to restrain the printed circuit board, while the lever on the left is spring-loaded. Rotating it releases the PCB so it can be removed or a new one inserted. I am currently working on a component that will hold the cross-piece. This component will have a spring-loaded ball in it that will drop into detents in the mating shaft to allow for quick rotation. The second two photos show the mating shaft being detented and a groove being added for retention. More photos when I make further progress! -- Regards, Charlie New Jersey, USA ? ANTHONY¡¯S LAW OF THE WORKSHOP: Any tool, when dropped, will roll into the least accessible corner of the workshop. THE LINDO COROLLARY: If you have cats, they will promptly hide the tool. |
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Bill Yes I did miss John D?s post reference "open source". Yes, John D has his own forum for marketing, so? maybe I can persuade him to change? his sign off when in the digitalhobbyist forum. It always reads?like an advertisement? which @ does not allow unless prior permission is granted and then you are in for added yearly payments for using a forum. I will send him a private email. Stay safe John L On Tue, 20 Oct 2020 at 15:50, Bill in OKC too via <wmrmeyers=[email protected]> wrote:
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John |
Bill in OKC too
John Lindo
