I've got a Clarke CL300 with a dodgy tailstock.
Ever since I've had it I've not been able to drill a hole reasonably accurately.
Lately, I've stripped the tailstock down to component parts and have been playing with them to find the problem.
It would seem that the base of the tailstock didn't sit on the ways particularly well and wobbled like a rocking horse.
I've since used a white board marker and a file on the ways to see where the high spots are and filed them out so that the base of the tailstock sits nicely on the bed.
The problem now is, with just the tailstock base tightened down to the ways and a DTI stroked across the top mating face of the base gives me a difference of 1mm in height from one side to the other!
I would like to know how I can possibly level out this tailstock base so that when I tighten the tailstock down, it actually tightens DOWN rather than at an angle.
I would have thought you need to put a centre in the tailstock and bring it up to the chuck to see if they are in line, this should tell you if one side of the tailstock is low or the other side is high. If one side is high then you need to remove metal however if one side is low you could use the epoxy putty trick favoured by JAZZCNC http://www.mycncuk.com/forums/router...html#post47815
Last edited by EddyCurrent; 18-11-2013 at 09:21 PM.
Can't quite understand whats going on here, any chance you could post a picture or a sketch, are your bedways flat, my tailstock base sits on a flat bed and is located between the bedways with an adjustable piece of square keysteel. the top of the base is slotted @ 90 deg to the ways and the tailstock casting is located and adjustable (for taper turning and setting true) in this slot.
If i can see the way yours is constructed i might be able to offer some advice.
hi again, I would have replied sooner have been quite busy.
My tailstock is similar to that one above, well, exactly the same.
You can see that the tailstock itself is in 2 parts, with the base that sits on the bed ways and the tailstock that slots onto the base.
Looking at the second photo, you can see the angular section closest to you that sits on the ways that aligns the base. On the opposite side theres a raised section that sits flat on the bed ways.
Well, on mine, the opposite side isn't raised and the machining was concave rather than being flat so the base on that side didn't sit flat on the ways.
So, being a numpty, I took a file to the base on that side to make the base flat and well, removed the concave area so the base sit flat but wasn't perfect, and at the same time made the base sit even lower on that side by 1mm in total compared to the angular side. I'm pretty sure I didn't remove 1mm of material with a file so I assume that it was already pretty bad on that side.
Because the base is so terrible and was terrible to begin with, the base sits lower on that side meaning the tailstock sits at an angle.
My plan is to glue a piece of brass sheet to the base on that side to raise it up and then using emery paper taped to the ways, using the angular ways to keep it all aligned, slide the base up and down the ways and grind the brass piece down so that the top of the base is level with the cross slide.
Once that is done, I can perhaps do something similar with the tailstock to the base as the bottom of the tailstock is also similarly machined bad.
I assume @ least the main bed is ground :) I would apply Engineers blue to a section of the tapered portion of the bed and mark and scrape the tailstock base until both flanks have consistent contact with your bed way, when blueing up make sure to apply pressure vertically directly above the "V".When your happy with that, take a small clamp and secure the base (directly above the "V") to the bed. now you have a reference you can check gap on the flat side with feelers and adjust with file and scraper to get a parallel gap and then make a shim to adhere to the base.
Rob, I don't suppose you've got a picture of the bottom of the base and ways? Just to entertain my own curiosity to know what it SHOULD have looked like on mine as mine was practically flat but in your picture it looks like it's raised.
Yeah, the bed is ground reasonably well I suppose.
I haven't got any engineers blue, but I have used a white board marker, but it's much thinner and doesn't transfer as well.
In the end I used some epoxy putty on the bottom of the base and pressed it down onto the ways with a piece of double sided tape backing between the bed ways and epoxy to stop it from sticking to the ways. Tightened the retaining nut down gradually sweeping the DTI from side to side until it was a little over level leaving myself a little to take off if necessary.
Unfortunately, I broke the putty off by mistake! It had adhered fairly well, until I put it in my vice to do the top, DOH!
Rob, it's much appreciated. Looks like it's off a CL300M too? When you say the quill is buggered what do you mean?
If it's not too bad I might be interested if it means I can just transfer the parts over. Let me know what you'd like for it. I have been tempted with a camlock stock from Arc, but £80 is a little out of my range at the minute.
I've redoubled my efforts and replaced the epoxy putty that broke off with a brass strip stuck to the bottom with araldite. Just waiting for the araldite to harden and I'll see how it goes.
Last edited by booski; 01-12-2013 at 08:22 PM.
Actually I have2 of the little sods, from a CL300M One has a quill with a damaged thread and the other is just the 2 casting pieces, but the top piece of it has a crumbled thread where a groove in the quill slides in a grub screw.
I have gone over to the camlock tailstock from ARC and it is a lot easier than pissing about with a spanner.
BTW I gave up trying to drill accurately, I spent a lot of time aligning the head and tail stocks. I took the chuck off and used an M3 taper centre in the head and the M2 in the tail. Height and Lateral were set up OK, but I don't think the stocks are on the same axis.
I have got a PDF of the CL300M user guide and parts list if you want it, but you can probably download it from the Clarke's website.
Anyway, you can have what you like of these bits and I don't want anything for them. They are going back into the garage after their 15 minutes of fame.
Cheers Rob, much appreciated.
So that's definitely a thumbs up then for the tailstock from Arc? and it's fairly reliable, easy to setup, accurate etc?
Actually never bothered setting it up, seemed good enough out of the box. I might use one of the old tailstocks as a base to make a fixed steady, when I need one. I would endorse ARC wholeheartedly, apart from the fact that they are just at the end of the road (14 miles down A46 ) The Clarke stuff is OK, but needs proper setting up. If I buy another small lathe or mill I would get it from ARC and have their main man set it up. Then I would only need to brush off the Hobnob crumbs and use it
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