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Re: Collet chucks
Same way the Atlas & South Bend lathes, among many others, do. The Atlas TH42 I have used a 1-1/2"-8 tpi thread, the SB 2-1/4"-8 tpi thread, and a flat register. There are better systems, now, but the only problems with them are that you have to keep the threads, both internal and external, clean, and that if you reverse the spindle, the chuck can spin off. With an independent jaw 4-jaw chuck, a dial test indicator, and a bit of patience, you can routinely expect under .0005" runout. Most of the time you don't need that kind of accuracy, but even before I took my class, I could do that. Instructions for that are at littlemachineshop.com in their reference section. Bill in OKC? William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Sunday, August 14, 2022 at 01:10:18 AM CDT, Keith S. Angus <keithsangus@...> wrote:
On Sat, Aug 13, 2022 at 10:30 PM, g steinback wrote: Many years ago Doug Collinge produced a nice tutorial on machining a collet holder -Just read through the section on cutting the recess in the back of the holder at 13 mm, and the explanation is just plain wrong. It is based on a failure to understand the precision that can be reached on these simple machines, a lack of appreciation of the actual clearances in standard screw threads and the clamping action when tightening the thread. All the experienced engineers I work with understand these things, and have no problem grasping how the 12 mm register achieves concentricity. |
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Re: Collet chucks
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On 13 Aug 2022, at 17:30, Jarod Alderson <alderj601@...> wrote:
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Re: Unimat 3 - Belt cover removal
Hello:
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On Sat, Aug 13, 2022 at 03:16 PM, @juliushenrymarx wrote:
... post the result when I am finished.Here we go: Keith's hot water method worked a wonder. I was terrifed the cover would break, but as the pins are shortish the plastic did not have to stretch too much. These pins are 3.0 mm and are a press fit in the plate that is 4.0 mm thick. Here is the pin hole and how a 3.0mm drill fits snugly in it. The plate being 4.0mm and the hole being 3.0 mm leaves a bare 0.5 mm for threading all around. Fortunately I have a Greenfield set with a 3.5x0.6 tap/die combination which is rather rare as the usual I see (when I see it) is 3.5x0.5. I was able to tap the holes with just enough threads to be able to put a screw in as the hole is not too deep and I don't have a snubby 3.5x0.6 to get to the bottom. The threads bit and in doing so actually caused the thin wall to bulge. But it is not an issue as the screws are not actually holding anything, they only have to stay put and act as a pivot. I did not have 3.5x0.6 screws so to get by for now, I made ~ 5.0 cm of thread to make the two set screws I was needing. ? Next week I'll get a couple of proper 3.5x0.6 screws, cut the heads off and dremel in a tidier slot. @ Keith: thanks again, you saved the? day for me.? 8^) @ John: thank you for your input. But there's really no need to get your nickers in a twist over my post. My opinions are just that: my opinions, to which I am entitled. Just as you are entitled to yours. Mine are solidly backed by over four decades of professional activity in my specific field which, BTW, include design and QC. Do have a good day.? 8^) Best, JHM |
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Second Pen harder wood
made a second pen now, its white oak and black fittings, it fits alot better, no over laps and sticky out bits
so based off last time 100% making/getting the custom holder instead of using the three jaw will help need to sharpen/reshape those chisels they work but on harder wood they catch almost ended up with a grove carved out of the pen do to that need to find a hose that my shop vac and hook into that is poseable and a way to clamp it to the table I am working on with that need to take the little unimat apart and clean up the screws and things, the size of my blanks dont let a small towel rest under them so gotta fix that somehow and lastly does anyone know where to grab a set of those low/non friction washers I have seen others use on their unimat rebuilds? the video did not list them in their parts to buy area so figured i would ask here, the carriage is what needs it most, some paint got in the bearing surface? and now it sticks alot? |
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Re: Collet chucks
Bonus! It contains a method of threading on the Unimat without buying the (rather expensive) threading attachment and guides! Will work for any thread, too! Just not for every object. Darn! But better than nothing! Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Saturday, August 13, 2022 at 04:30:24 PM CDT, g steinback via groups.io <gsteinba52@...> wrote:
Many years ago Doug Collinge produced a nice tutorial on machining a collet holder - /g/Unimat/files/ER-16%20Collets/Unimat%20ER-16%20Collet%20Holder.pdf Jerry S |
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Re: Collet chucks
Left to right - left) purchased chuck with M12x1? thread to fit direct on the spindle nose.? Centre) collet chuck with 16mm plain bore.? Right) collet chuck with 12mm shaft - intended to make up a sensitive tail stock collet holder - certainly the later 2 originate from China via eBay. Cheers Richard |
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Re: Unimat 3 - Belt cover removal
In nearly every company, you start with a product designed by engineers. As that product is successful, and the company makes money, the accountants take over, and try to cut expenses to the bone, while still producing a salable product. And eventually, they cut past the bone, and the product stops selling, and the company goes under. Some companies have so many products going out that the progression lasts a really long time, and a very few may survive it...? Not sure EMCO is one of them.? Bill in OKC William R. Meyers, MSgt, USAF(Ret.) Aphorisms to live by: Good judgement comes from experience. Experience comes from bad judgement.? SEMPER GUMBY! Physics doesn't care about your schedule. The only reason I know anything is because I've done it wrong enough times to START to know better
On Saturday, August 13, 2022 at 01:16:36 PM CDT, <sawbona@...> wrote:
Hello: Thank you for the prompt reply. Much appreciated.? 8^) On Sat, Aug 13, 2022 at 02:34 PM, Keith S. Angus wrote: ... a fight with this on mine ... ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? ????????????????????????????????????????????????????????????????????????????????????????? ... had a new one to fit.????????????????????????????????????????????????????????????????????????????????????????????????? ? ?????????????????????????????????????????????????????????????????????????????????? ? ? ? ... just pins inserted into holes ... ?? ???????????????????????????????????????????????????????????????????? ? ??????????????????????????????????????????????????????????????????????????????????? ? ? ? ? ? ? ?? ... can't get them out with the cover on ...No way! Absolutely un-be-lie-va-ble. I tell you, the more things I discover on the U3, the more I think that whoever was in charge of design/quality control was a certified clown. So much for the famed Austrian industrial quality, just cannot see it here. ... only way to get the cover on or off is to bend it until it clears the pins.Ahhh ... As I was not finding any other possible way, I started to look at the possibility of doing exactly that. But I stopped and reflected: it can't be that, I'll break the cover. There must be a plausible explanation to this problem. And all this time there I was assuming a previous owner had somehow screwed it up or taken a punch and hammer to it. In another life, working first tier IT support in a ministry, I put this phrase over one of my monitors: "Never ascribe to malice that which is adequately explained by incompetence" This U3 belt cover situation fits like a glove.?? 8^¡ã ... on a warm day ...?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ... warm it in a bath of hot water first.Thanks for the info and the hot water tip. If the pins can come off, there may be just enough room in the holes to thread for an M2 screw. If not, longer tight fitting SS/piano wire pins that can be twisted and pulled out. That would avoid problems like this one in the future. I'll post the result when I am finished. Once again, thanks a lot. Best, JHM |
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Unimat 3 - Belt cover removal
Hello:
As part of my on-going task (installing a 24v DC motor on the U3) I have come to the point that I need to detach the belt cover from the motor's mounting plate. Here's the page from the manual showing the whole assembly, which refers to it as the clamping plate: From the drawing and the corresponding legend, it is clear that part #12 is not one but three parts: the clamping plate and the two pins/screws that make up the pivot for the cover. As you can see, they are shown as being inserted/screwed from the outside of the cover in. But I cannot make out any sort of screw head ie: flat head, phillips, allen, etc. Looking with a loupe and better lighting, I was not able to make out any trace of a screw head. ie: being this U3 second/third/fourth hand, some indication of a previous owner's haste/lack of patience/sense. So ... If not screws, could they they be pins? And press fit at that? It would be a rather strange design choice but, given others I have seen on the U3, not impossible. In any case: anyone here knows how to you get the bloody things off? Thanks in advance. Best, JHM |
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Re: Collet chucks
Jarod
I would definitely be?interested. Keep my email handy if you decide?to sell. On Sat, Aug 13, 2022, 1:39 AM Nigel Pearson via <nigelpearson=[email protected]> wrote:
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Bill in OKC too
