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| Project 1: Taper attachment clamp |
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| AdeV:
:proj: OK, this is going to be Lathe Project 1; mainly because it doesn't involve much lathe work! And lots of milling work, which I'm better at. At the moment... Readers of my lathe thread elsewhere will be familiar with the problem; I have no way of locking the taper attachment to the lathe in order to actually cut a taper. Davo J suggested a device which clamps to the ways, and this is exactly what I will do. It also has the benefit of being a relatively straightforward job, which is nice for a beginner like me :thumbup: Now, before I get started, some excuses.... I'm not getting as much shop time as I'd like at the moment for a couple of reasons: Work, and the cold weather. The former is self explanatory; the latter means I can't do much work in their before my right hand turns into a world of pain. It's a sort of RSI type thing (25 years of bashing on computer keyboards, or nearly 70% of my life, and I STILL can't touchtype with more than 2 fingers); basically, I lose all strength in the hand & the whole back of the hand just gets more & more painful. Which is bloody irritating, pardon my french. I may have to try some fingerless gloves to see if that cures the problem. Oh, and the other thing, I got a bit of brass swarf in my index finger, and boy does that sting. ::) Expect it to be a few weeks before it's all finished... Anyway, excuses done, here's the plan - And pretty well straight away I need advice: That bit should be self explanatory. I'll thread the end of some stainless bar so it goes as far into the taper unit as possible. The bars will probably be about 8" to 10" long, in total, I don't think they'll need to be longer. There's only so far I'd want to wind the carriage back along the taper, after all. I've then come up with two possible designs for the actual clamp unit. I envisage each one using between 4" & 6" of space along the ways; and will be deep enough + a bit to catch both sticky-outy-rods. I will probably make it from a lump of steel (milling out some material if it's too heavy); or I'll get the welders to rough one up out of thick steel plate & then mill it to size. I don't have any C-o-C facilities here (no scanner or camera @ home), so I had to use some real cad. Fortunately, I took screenshots to keep that C-o-C feel. And there's no dimensions either... :hammer: Option 1: A (in red) represents the cross-section of the lathe ways. I have around 1/2" underhang on the left-hand-side (inside edge), and about 5/8" on the outside edge - but I can't use both underhangs at the same time, only one of them; otherwise I'd have to remove the tailstock to fit/unfit it, and the tailstock couldn't be brought forward past the clamp. B (in white) is the taper clamp, as seen from the side. The dodgy yellowy bit is a gib strip, either in brass or steel, TBA. The green bolt (C) clamps up against the gib strip & pulls the taper unit onto the backside of the ways. There'll be two bolts, I think, to even the load on the gib strip & maximise the holding force. Any slippage could be disastrous to both the material being cut, as well as the cutter & maybe even the lathe itself. So slippage must be avoided at all costs. Note that "B" is shown using a fair amount of the underhang on the outside of the way; I don't think this would be possible whilst retaining a snug fit on the ways, so I'd use the inner underhang (as a "hook") instead. Moving on, the two stainless bars sticking out of the taper unit fit through the almost invisible holes D (in blue). Bolt F (cyan) clamps the holes by pulling slot "E" (pink) closed. Again, there'd probably be 2 bolt F's. Later on, I will replace the bolts with handles, but as I can't draw them in AutoCAD, it's a fair bet I can't make them yet either... Advantages: it will clamp the ways really firmly, and since neither face is a sliding face for anything on the lathe, it won't add any wear or warp even if it's really scraunched down. Disadvantages: It may interfere with the tailstock (but perhaps I could avoid that by using longer bars, allowing the tailstock to be moved inboard of the taper clamp); it looks very difficult to machine with just a mill; maybe making it in 2 bits & silver soldering them together would make it easier, but would it retain enough strength? Option 2: This works in exactly the same way as the one above. Even the letters and colours match. Woo. Advantages: Much easier to machine; tailstock can be moved past the unit as shown, so it could be left permanantly attached (just unclamped to the ways in normal use) Disadvantages: Less clamping stability, there would be a tendancy for the clamp to try to twist as the carriage moves backwards & forwards. The top clamping surface is also the slide for the carriage, so it's a wear surface & is covered in oil (which will reduce the clamping effect). There's a couple of things I can do to this one to help mitigate the disadvantages: I could use a little bit of that slot (not much, as the tailstock also uses some of it) to provide a "hook"; but I'd have to put the gib strip & clamp bolt on the underside, so the lip that goes into the slot is pulled into it, rather than being pushed up out of it (as would happen with the current design). On balance, I prefer option 2 for the simplicity & the fact I can leave it on the lathe most of the time; but I'd appreciate people's thoughts as to how well it's going to clamp onto an oily & smooth surface. If the danger of slippage is too great, then it will have to be option 1. Gents - if it were you making it, would you do option 1, 2 or 3 (which I haven't thought of)? Your input will be very much appreciated :nrocks: |
| kvom:
I had to make mine as well (Monarch 10EE). I replicated the original Monarch design as much as possible. As your ways have a similar profile mine would work for you as well. The clamp is two pieces. The heavy main piece has a lip that fits the space between the flat and V ways. The clamp part is similar to your 2nd drawing except it is a piece of aluminum that bears on the bottom of the square way. The clamp bolt passes through the main part from the top. The Monarch has only a single bar that connects the TA to the clamp. It passes throughn a horizontal hole bored in the clamp, is threaded on both ends, and two bolts are used to secure it to the clamp. |
| sbwhart:
Hi Nice intro to project :thumbup: I'd go for option 2 with a little hook added that goes into the way groove as shown in Kvom's pic Have fun Stew |
| Davo J:
I agree with Stew, if not go with your option 2. If you went with Kvom's idea but wanted to make it all out of solid like your pictures,you could slide it on from the end of the bed and it would be semi locked in place. I would love a taper attachment on my lathe, maybe one day? Dave |
| AdeV:
Thanks kvom, I like the idea of the underside pulling up; it gives me the best of both worlds - an accessible bolt/handle, and a pull-down clamping action. I did a bit of measuring, and I've got just about 0.100" width of that slot that I can use before fouling the tailstock; I can go slightly oversized on that & fettle it to fit, as the more meat the better on that bit. By keeping to that dimension, I can leave it clamped to the taper attachment more or less permanently, unless I'm turning a really long bar & need the carriage right at the end of the bed. This is the new design: This now works in exactly the same way as the kvom/Monarch version, bolt C pulling up the unlabeled yellow piece (ali, brass or steel: I haven't decided yet). Also, as I don't have a slitting saw, I've changed the clamp to work in the same way. The bolts are shown here with the thread at the top end; in fact, they'll be plain shank all the way through piece B, with the threads only being used to draw the yellow clamping parts up. One last difference; bolt F will draw against a flat, not a slope as shown here... and it'll be centred between the circular cutouts so it clamps each one with approximately the same force. Interestingly, the Edgwick page on lathes.co.uk almost shows enough of the taper attachment; what is interesting is there's clearly a single very long bar sticking out of the back of it, as can be seen here, indicated with the blue arrow: (picture credit: http://www.lathes.co.uk/edgwick/page2.html) Unfortunately, the clamp, whatever it is, is not shown - or maybe it's hiding behind the tailstock. |
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