Too late I discovered that both my big chucks are just a bit too small to handle the current batch of dial faces. Thus I was able to clean the outside edge and the face (using an angle grinder with sand disk followed by sand paper while the face is rotated in the RedNeck lathe) but doing the inside of the ring presented a problem as I could not grip it on the outside. In the end I solved it this way:
Using a mini-mill to bore out a 3.18" ID hole with a 2" boring head probably comes under the "dogs walking on hind legs" category (on the whole done badly and probably should not be done at all). Yet in the end it worked (see the next picture of the semi-finished product). Of course the speed adjustment was critical and the boring bar advanced by 0.005 at a time.
I thought it would have been better to have the bar clamped in the transverse hole of the boring head but then the head would have to spin anticlockwise which my mill does not do. Are there tools that can be used this way? Presumably one can make a custom boring bar with a carbide insert. Is that feasible?
Are any of your chucks (hopefully, the larger ones) equipped with two-piece jaws? If so, you could make some soft jaws from aluminum which extended out to handle larger diameters, given that you don't have much torque available in the "lathe" anyway. The main question is whether such extensions would hit the bed of the lathe.
It is slow, but it works. That is what matters, as long as this is a hobby occupation, not one being done for serious income where time is money.
Most serious sized mills will rotate the spindle in either direction. But you need to beware that the shank is screwed into the head, so too aggressive a cut will unscrew the head.
However -- clamp it in the transverse hole with the cutting edge pointing up, and back it out of the hole instead of plunging into the hole and you can use your existing tool in the direction of rotation that your machine is willing to provide you.
Or -- use the mill to make new top jaws as I suggested above, and do the boring on your lathe. (Not sure whether you have enough rigidity to handle the boring there, and you can't get the angle grinder inside the hole.)
Hmm ... beware that the angle grinder will spit abrasive junk which can cause accelerated wear in the chuck's jaws where they move in their ways.
Yes -- with the right inserts.
And if your lathe is rigid enough (something that I doubt) you could take a cheap insert turning tool designed for left hand turning (turning a face on the left hand end of the workpiece), and turn the shank from square to round for most of its length so you could slide it into the boring head's holes.
The bigger chuck is actually a wood working chuck. The jaws are held in their tracks by screws and it that respect the jaw is *4-piece*. I thought about making some sort of extension but could not get my head around the process. There is plenty of space under the chuck (I wanted to turn up to 9" OD).
Tell me about it...
So you think my mill is a joke? Well, it is. Sort of :-) This was brought home to me when I visited the Busy Bee shop in Vancouver where my mill is side by side with other mills. Even the next smallest one was, well, bigger.
Aaaargh! So close! I got it set up like that but did not think of *backing out* .
But Dremel and various rotary sand heads will :-) I think the rigidity is a concern. The preliminary tests have left me unimpressed but I have not got the tooling fixed to the bed properly
Oh yes! It threw it all over the part of the workshop where I did not really want it. Half an hour clean up...
Or just hold it in a tool post. The stuff I got from auction has one or two small boring bars that the guy made to fit just like that.
I did a detour: I tried to finish a 4.5" ring on my Taig to see if it is a) feasible and b) what is the result. It was a bit tricky as 4.5" is about
1/16" inside the taig swing but I sort of managed it. I haven't finished it yet as I need to shim the ring to get at the innermost aspect without knocking the jaws but it can be done. whether the finish obtained is something that will be useful (many concentric rings instead of smooth) remains to be seen.
Again, it was a very slow process given the lowest speed of 570 rpm. The most difficult part was moving the carriage by very small amounts without a leadscrew (another project for the future!). And the place swims in coolant.
I though about that but did not finish the thinking through. I was so hung up on doing the outside first. You are quite right. Gotta get me one of those. In terms of practical details: When making the wooden face plate would you drill a central hole, tap it for 1"-8 and then finish the outside with a gauge/skew chisel or would you make a smaller metal face plate (I milled a 1"-8 nut some time ago with a view of welding a metal disk to it to make one like that) and screw a piece of wood to it (finish as before)?
Did you try turning the chuck jaws around? That should give increased grip.
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When using the sanding tool, you will not need that much rigidity by comparison with true metal turning.
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You did not get the 3-jaw chuck for it did you -- only the
The 3-jaw has two-piece jaws, with the top jaws made of aluminum. You can turn the jaws to have a small step and grip just a bit thinner than the workpiece stock, and this eliminates that problem at least. (And if you *do* "knock" the jaws, they are easy to replace, and with your mill you can make spares from scrap aluminum if you so desire.
Coolant on a Taig? I've never seen that before. :-)
I'd use the largest metal faceplate that fits and attach a wood face to it. For a home-made lathe the faceplate would probably be a large cast-iron pulley driven by the rim so there's no torque at the spindle. This type of shaft mount is considerably stiffer than a sliding fit and setscrew:
There is one on the motor shaft on the left:
Alternately you might salvage the pulley from a broken air compressor. I think the built-in fan blades make them stiffer against axial pressure.
I had to to try and grip outside. That is when I discovered the problem. Foolishly I expected a 6" chuck to grip a 6" workpiece.
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Yes. They clean but do not shape. So for instance the face of the dial is nice and clean but not truly flat.
I am heading that way. However, it is a matter of priorities. With the Father's day coming and all, I did a little prep yesterday should the children suddenly remember to be grateful: Just the Little Machine Shop potential tally came to $1048 and they do not even do many Taig things (not the chuck, but a very nice QCTP!).
Coolant on the Taig. Coolant on the bench. Coolant on the floor. Coolant on the cat... With the temperatures reachin 37 degC I could have done with the coolant myself. The 1/4 HP motor did not like working in that heat.
I think I understand. I found them on McMaster-Carr web-site. Major re-engineering would be required. If one did that one could use the faceplate only? There would be no option to change chucks etc.? Maybe I shall try this first:
At the price I cannot make it myself.
If I understand you right for the purpose I intend it for the pulley would have to be attached "inside out", i.e with the bushing at the back of it, right?