Here is a list of all the postings Alan .204 has made in our forums. Click on a thread name to jump to the thread.
|Thread: Using A Taper Attachment.|
Worked a treat Andrew, lovely finish in the taper bore 1800 rpm 4thou feed rate. 20 depth of cut, that saved the part, thanks for the advice.
That’s the stuff Andrew saying as hard he’ll minght not be the right phrase more like just tough, I’ll try increasing speed and feed if it doesn’t work out I’ve managed to find some mild steel that shoul do the job, you know what it’s like you find a piece the right size and think that will do just fine 🤔 any way positives are I’ve had plenty of practice with the taper attachment and learnt a lot along the way so all good.
Thanks Andrew, Alan.
So far after doing some adjustments on the lathe gibs and also checking the gibs on the taper attachment I used a piece of scrap mild steel and cut an 8 degree taper for my ER collets, every thing went realy well, so next was to make it for real and then the problem has started, the steel I have is I think called SS99 it’s as hard as hell but I went nice and steady managed to internally thread 1/500 x 8tpi I made a carbide threading bar to do it, cutting the taper how ever hasn’t turned out well at all, the finish in the bore is shite to be honest the only thing that’s different is the steel, very tough to turn, when turning the taper I’m going in the conventional manor ie right to left and normal rotation of the lathe, my question is would I get on better if I was using a right hand tool turning the back of the bore so to speak with the lathe spindle running in reverse, I’m thinking of backlash if there is any in the taper attachment, think of it like climb milling on a conventional mill, hope ive made sense, I’ll continue with this part as it only needs the threads for the collet nut so I may as well finish it, should have said that I’ve tried all manor of different boring tools on this and there’s realy no difference in the finish, best I can describe it is it has ridges along the bore, even after a realy sharp carbide boring bars been through taking 0.1 mm cut them a spring pass also both at speeds ranging from 130 / 425 rpm at .001 feed rate,
|Thread: Thread Pitch Info.|
Brian the thread pitch gauge is a perfect fit, the 60 degree pitch gauge fits not the 55 degree Whitworth I checked it also, It may seam like a bit of pissing about but it’s been a good learning cure especially on a metric lathe, it’s done now and it came out on size and fits the dividing head realy well just have the taper to do on the other end then it’s finished.
Thanks again, Alan.
1.364 is what I've gone with and all seams OK, it's a Vertex dividing head and the thread is 8 unc I know it's uncommon for this head as I bought a back plate for this module and it didn't fit the supplier couldn't belive the size and thread either till I sent him some photos of it, it really is an odd ball, maybe it was made at the end of the day on friaday, Jason I have a female thread to measure but the fit really is shite hence cutting a new one. I wanted to get it right, with the help received from you guys I'm nearly there so thanks every one, by the way I did measure it with a Whitworth pitch gauge, close but the imperial thread gauge is pretty much a perfect fit not pretty much it is.
Thanks for that, I get a bore size of 1.314 inch am I right?
Ok chaps now I’m struggling with this thread I’m trying to cut, I’ve checked things again, OD of the screw thread is 1.5 inch I’ve checked the thread pitch again as I’ve found there is a 1.5 inch / 8 tip in BSF but it’s not that, it’s defiantly UNC, how can I work out the bore size for the internal thread, I know some of you chaps minght think it’s easy to do but it’s not when you don’t have a clue, can anyone explain how u do it, instead of knowing getting the bore size I would like to know how to work it out for myself for future refrance.
I’ve got 1.498 for the bolt and 1.349 for the nut should be ok with that hopefully.
Hi David, no mate it’s defnatly UNC 8tpi, said it was an odd ball, I’ll see what I can find on the net, i would like to start it tomorrow just need the thread info.
Should have said it’s UNC
i want to make a ER32 collet holder to fit on to my dividing head, the spindle thread measures out to be 1.5 inch OD with 8tpi it’s a bit of an odd ball I think any one have any info on the thread data for this, internal data I mean ?
|Thread: Upside down reverse threading|
John, when the tip of the insert is where I want it I set a DTI on the bed way so every time I come back I start in the same place, I have brocken tips yes but not doing it like this, as for plunging what ever the finished depth is I go to depth in full then come back to the start of the depth so to speak and add more depth each time I make another pass, I’ve had no problems at all, give it go if you don’t believe me, I will be making some collet holders soon I’ll put it on my ytube channel you can have a look if you want to, just because you haven’t done something a certain way yourself doesn’t mean you should dismiss it ?
I do all my threading with an inverted tool away from the chuck, no need for thread relief either, I just go straight into the finished depth pull back out then thread in stages as normal just in reverse, works a treat and more importantly for me safer.
|Thread: Taper attachment|
Sorry for the mitiple pictures, this site has a mind of its own sometimes.
I managed to have another go today so here’s what happened, first I did not alter anything, I did as Andrew suggested and turned a piece of bar to 20 mm then fitted a collet on the bar, set up a DTI and ran it along the collet, using the taper attachment it stayed perfectly at zero, Was not expecting that, turned the chuck 180 and did the same this time with .0015 of runout turned another 180 and zero runout again, I put this down to the collets as there cheap ones, so the set up was fine, so the issue I thought must be when I’m turning so I adjusted the cross slide gib and the top slide, gave everthing a good clean at the same time, cut a new taper and it worked out really well, cut some threads on it fitted the collet and nut inserted a 16mm carbide end mill init and checked the runout, .001 out so happy days, the taper attachment on my Colchester Master 2500 is the type where you just clamp the fixed bar on the lathe bed and away you go, no need to remove the cross slide nut, I’ll include some photos so you can have a look.
Once again chaps thank you very much for your help, ps still hate maths.
Edited By JasonB on 13/05/2019 06:59:03
Once again chaps you’ve all come up trumps with some great advise as normal, it’s realy good to know you can get some good advise when your struggling a bit, Tony your question about the right triangle may as well have been written in German as I’ve know idea what your asking me, but I’m great full you took the time to try and help me out , as I said preaviously maths and me are not good friends, Jason, the thing I was going to try tomorrow is the same as you’ve suggested, still stumped on why it’s so far out though, Clive, great explanation of how you go about this type of thing, food for thought in the future, Not Done It Yet, I’ve not used the taper attachment yet so I thought it would be a bit of practice I’ve cut these before using the top slide but thought I would give the taper attachment a go, glad I did as I’ve leant a bit today playing with it, Dave thanks mate, as I said above I just wanted to try it, tomorrow’s another day I’ll let you all know how I get on.
Thanks Chaps, Alan.
Well this afternoon I’ve had another go at the taper, but I’ve still got something wrong,the taper is to great, I set an indicator on the ways to zero and another one on the rear of the top side, with one inch of travel I get 140 thou of inward travel so I thought happy days but no, tool is dead on center hight I’ve made sure I come back far enough to account for the backlash on the taper turning attachment, the info I found on the angle for the ER 32 collet taper says 16 degrees included so I’ve worked it on 8 degrees, am I right ?
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