MadModder
The Shop => Tools => Topic started by: Lester on June 17, 2016, 05:01:54 PM
-
I've been running my PD 400 for several years now, generally very happy with it. The only ointment on the fly for me is the tailstock. I mainly turn aluminium, brass, and acetal for toy boats, and sometimes small stainless. The tailstock simply won't carry a 10 mm drill bit into aluminium without wobble. I think the rest of the lathe is up for this, so am looking to source a better tailstock. Does anyone know where I might look, please? Many thanks!
-
Lester,
Just been looking at the spec for that lathe, and the cost (£2000 +vat), so one would not expect it to wobble.
Have you identified exactly where the wobble is occurring ? By that I mean is the whole tailstock moving or is it the tailstock quill ?
Also, does it do this if you drill up to 10 mm incrementally ?
I'm assuming it isn't something silly like a bent drill.
Dave.
-
Lester
have you tried stub drills, after piloting it with a slocum type?
The slow spiral aluminium drills work well but need lots of WD 40 to lubricate.
-
Iff a drill is not sharpened corectly it will wobble regardles of the tailstock , have you tried a new drill ?
-
Is the tailstock accurately aligned with the spindle? I had a problem on different lathe where the centres did not align causing centre drill tips to break off ( the tiny ones). Also made my drilled holes oval.
-
Hi folks
Thanks for your suggestions ... actually, I really am looking to replace the tailstock (smile), would love to know of any possibilities!
Hi DavidA,
> is the whole tailstock moving or is it the tailstock quill?
The quill is certainly wobbling in time with the drill bit, and the tailstock is showing some of that movement which is imperceptible by the time it gets to the bed which is pretty rigid.
> Also, does it do this if you drill up to 10 mm incrementally?
Sure, no problem if I drill 3, 6, 8, 9, 10. But life is too short! OK, I don't just want to drill 10 from a centre punch, happy to do 6 first; but it will wobble when the quill has travelled 25 mm in this case in aluminium.
> I'm assuming it isn't something silly like a bent drill.
Nah, nothing silly!
Hi howsitwork?,
> stub drills
I run a stub 6 mm when I need to just drill a short damn hole immediately, but anything longer requires the 3, 6, 8, 9, 10 sequence.
> piloting it
I use a centre drill routinely, and then run the 3, 6, 8, 9, 10 sequence.
Hi chipenter,
> have you tried a new drill
Yes, my drills are sharp and new every year or so or when I notice any performance degradation.
Hi gerritv
> tailstock accurately aligned with the spindle
Now that is one of the issues with the tailstock, there is absolutely no way to adjust alignment. Fortunately, it is acceptably good, but I would prefer to get it spot-on. Hence, I really am looking to replace the tailstock.
-
Could you bore and sleeve the tailstock in an attempt to get it true to the lathe bore. Otherwise you are probably looking at fabricating something. Again not the end of the world as your head will be doing the boring so it should all be inline, at least to the error in the headstock :lol:
-
Have you tried putting a true bar in the lathe tail stock (Mt 2 ?) and clocking the run out with a dial indicator mounted on the cross slide ?
I know you did say that your tail stock run out was 'Fortunately, it is acceptably good,', But what is it ?
There seems to be something fundamentally wrong here. Tailstocks generally don't give trouble. Particularly Swiss made ones.
Dave.
-
Joules,
I like the boring option.
Carefully set up the fixed steady on the far side of the tail stock and insert boring bar. Or set up a dummy tailstock.
Dave.
-
I have a Japanese Toyo lathe which people say Proxxon copied. The tailstock is rock solid but I would say it was never designed to hold a drill bit as big as 10mm. The tail stock chuck on the Toyo is 0-10 mm but I think that is optimistic.
-
Hi Diagnosticated
Your friends might have been thinking more of the Proxxon PD 230/240, which has similarities to the Toyo. The PD400 is something of a different animal, with a headstock, gearing, and cross slide that is competitive with, say, the Myford ML7 which my friend has. But the tailstock of the PD400 is where Proxxon cut their costs... Photos attached, showing that it is a simple casting. It clamps to the bed well enough, but has no other adjustments to align with the headstock... I would like to hear if anyone knows of an after-market replacement! I understand that I can ream it, sleeve it, or make my own (!), but I really just want to hear about the possibilities of replacing it. Thanks!
-
Lester, you just aren't going to find a drop in replacement. The odds are these things are machined with the headstock on the same setting. A replacement from Proxxon won't be inline if they supplied them, and that probably accounts for them not being a replacement item. The centre height of your machine is going to be unique. Fabricating your own tailstock and machining it using your headstock is the only way to guarantee it will line up correctly. You do have some adjustment screws on the side, however you really need a between centres bar (accurately machined) that you can put between centres on your machine and clock it at each end and along its length.
:palm: The side screws will be the anti rotation for the tailstock.... Oh well...
-
That tailstock looks identical to the Toyo tailstock. Except toyo/manix use plastic handles which are not nice. I bet the toyo tailstock will fit your lathe. The toyo is now made by manix in Korea but it doesn't help you as spares are almost impossible to source. I just bought a boxford lathe because my Toyo small lathe struggles too much with bigger drilling, larger diameter turning.