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Post by terrier060 on Apr 4, 2019 17:49:54 GMT
The top picture shows the part-machining of the bypass locking plate. I then intend to mount the plate in a chuck or collet on the Tormach and machine the rest. The top left is pocket milling the slot, followed by adaptive milling the locking bracket. The third operation is another adaptive one to clear out the unwanted tube and finally the spot drilling for the bolts. This is the most complicated operation I have done and may fail miserably! Simple compared with some of the amazing operations that Roger does. Bypass 02 by ed cloutman, on Flickr Bypass block by ed cloutman, on Flickr
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Post by Roger on Apr 4, 2019 18:22:39 GMT
Hi Ed, Just be aware that if you're holding the part buy the small diameter, you won't want to mark it by holding it too tightly. If you try a full depth cut, it's likely to come flying out of the chuck. I'd use small depth cuts of no more than say 0.5mm deep and take your time. It's better to take a couple of hours rather than scrap it. Personally I'd have done it in the reverse order, ie machine the end detail on the Tormach and then turn the back details and finally part it off.
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Post by terrier060 on Apr 4, 2019 21:15:14 GMT
Yes Roger - what you say makes a lot of sense. Will try it that way for the next 3. The difficulty is trying to think ahead in 3D when one is dealing with a solid block.
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Post by Roger on Apr 4, 2019 21:34:32 GMT
Yes Roger - what you say makes a lot of sense. Will try it that way for the next 3. The difficulty is trying to think ahead in 3D when one is dealing with a solid block. Hi Ed, It looks like you've only modelled the part that gets milled. Personally I always model all of it, then I always have a complete record of what I made but it's also useful for either creating a 2D drawing or just interrogating the model to get the dimensions when you're using the lathe.
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Post by terrier060 on Apr 5, 2019 9:10:00 GMT
See previous page Roger - drawing there - but point taken.
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Post by terrier060 on Apr 5, 2019 22:47:29 GMT
Well not a very productive day I am afraid. I don't know what I am doing wrong, as I have set everything up the same as usual, but the tool offset does not seem to be working correctly on the Tormach. The program is loaded and the tool appears to go through the correct motions in the correct position relative to the work-piece, but it does it all about 3/8 inch above the model top. Yet the tool works correctly in the Fusion simulator. In all my previous jobs, if it works OK in the simulator, it copies exactly on the Tormach. Any ideas would be gratefully accepted. I tried setting up the Tormach from scratch three times today, before I gave up. Bypass CNC by ed cloutman, on Flickr
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Post by Roger on Apr 6, 2019 7:11:50 GMT
Hi Ed, The zero looks to be in an odd place on your model, I'd have expected the CAM output to be referenced to the top of that flange, not the top of the base. I presume that's the zero for the CAM rather than the zero for the 3D model? How do you set the CAM zero? The simulation will work and appear to be correct regardless of where the zero is, at least it does on Alibre CAM.
Maybe you can load a program that you know has worked before and double check that the machine appears to be at a sensible height for that job.
You'd have to touch down on that lower flat face with the Z-axis setting probe to get it to work the way you've got it shown. Maybe you intended to do it that way, but I'd strongly advise to always use the highest point wherever possible so as to avoid confusion and collisions. If you probed the top as it's shown, I'd expect the machine to be working too high by the difference in height of those two features.
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Post by terrier060 on Apr 6, 2019 9:21:23 GMT
OK Roger - I understand what I have done but not sure how to change it.
I have changed the origin to the model origin which has put it at the centre of the circular base on the original sketch.
I need to keep it in the same place but move it to the model top. Do I need to make an offset plane to do this?
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Post by David on Apr 6, 2019 9:28:24 GMT
You can set the CAM setup origin to a different place than the model's origin. I've had to do it most times because I forget to model with the origin and orientation where I want it on the machine.
In the Edit Setup dialog where you define the stock etc, the first tab allows you to set the origin and orientation for that setup. It defaults to be the same as the model but you can change it to define two of the 3 axes and a point on the stock or the model to be the origin.
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Post by terrier060 on Apr 6, 2019 9:50:00 GMT
Sorry Roger - our posts have crossed and you have answered me perfectly (must have read my mind). I will see if I can find a way to do it!
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Post by terrier060 on Apr 6, 2019 10:06:48 GMT
That seems to have done the trick - I drew a circle on an offset plane over the origin - then reset the origin in setup. You learn something new every day! I will try it out now and see if I can cut metal! Correcting Origin by ed cloutman, on Flickr
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Post by Roger on Apr 6, 2019 10:47:40 GMT
Hi Ed, I build my models upwards from the origin, so I always have to set the CAM origin to wherever I need it. Alibre lets you either put the values in manually, or lets you choose from all of the 27 possible corner and middle combinations of the containing box. In other words you can choose top middle or bottom for the Z-axis and front middle or back for the Y-axis etc. It usually use middle for X and Y and top for the Z axis. On your model it makes more sense to use the X/Y as Zero since you can clock up on the diameter though.
NB:- You'll need to be able to set the Z-axis to the middle of the bar if you ever machine something on its side. That's because you often need to rotate the part about the centre of rotation of the rotary table and it's vital that this coincides with the centre of the model. In other words, really getting to grips with where the CAM zero is and what that means for setting the zero on the machine is absolutely vital to avoid collisions.
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Post by terrier060 on Apr 6, 2019 22:19:30 GMT
The problem with this model is that the centre of the stock in this case is not the central axis of the model. The bracket throws the centre off which is why I had to set it manually. Only I did not take into account that by manually choosing the centre of the sketch, it threw off the axis to the sketch and not the top surface of the stock. Stock origin by ed cloutman, on Flickr
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Post by Roger on Apr 6, 2019 22:57:22 GMT
That sounds like Alibre CAM where you can set it manually. In my case, Alibre can be used to automatically set to the centre and top of the stock, and then you can go back and over type any of the offsets. It's handy doing it that way because it means you don't have to work out or measure the offset to the top of the part. I presume you wan't to make the centre of the radii the origin so you can clock it up and call that position X0Y0.
Alternatively, you can output the job with the offset as shown. Since you can go and see what the offset is from the centre of the base to the CAM origin, you could clock up the base and then type in the offset instead of zeroing the DRO. It all amounts to the same thing, it's what you're happier using really. Personally, I'd over type the CAM origin to read X0Y0 and leave the Z offset as shown in the picture. Clocking something and setting it to X0Y0 feels more logical to me.
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Post by terrier060 on Apr 7, 2019 22:29:30 GMT
OK it took about an hour to do but the 1mm cutter did a good job: 3000rpm at 3.5in/min and depth of cut 6 thou. In the end I let the Tormach do a light cut around the top of the bracket to mark out the edges. Then I used a piercing saw and cut the bulk of the metal out and filed to finish. It took about 10 minutes. Bypass bracket by ed cloutman, on Flickr
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Post by terrier060 on Apr 9, 2019 10:52:20 GMT
You know, when I started building in 7.25G I thought it was nice and large - not many small bits. I am now reduced to watchmaking and I am now losing bits as fast as I make them. PING! off they go into oblivion. 3/32" diameter brass rod - threaded 12BA (nerve-racking with a Chinese carbon tap) then PING and I have to make another one. Then there is the angled hole to take the operating lever made of 1/16" brass rod - nicely tapered then PING - another one gone! I haven't got as far as joining the two yet because they have all PINGED away.
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Post by Roger on Apr 9, 2019 16:12:41 GMT
You know, when I started building in 7.25G I thought it was nice and large - not many small bits. I am now reduced to watchmaking and I am now losing bits as fast as I make them. PING! off they go into oblivion. 3/32" diameter brass rod - threaded 12BA (nerve-racking with a Chinese carbon tap) then PING and I have to make another one. Then there is the angled hole to take the operating lever made of 1/16" brass rod - nicely tapered then PING - another one gone! I haven't got as far as joining the two yet because they have all PINGED away. I presume you're making studs? I always buy the longest length bolts because they're pretty much the same price whatever the length. Then, when you need short ones, you can cut them down and when you want studs, you cut the heads off. If you use Metric sizes, you can buy them at almost any size and length you want for next to nothing on eBay if you just want threaded rod. If you want studs which have threads at both ends, you can buy long tiny Cap Screws and then you only need to thread one end.
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Post by terrier060 on Apr 10, 2019 18:13:41 GMT
Thanks Roger - that's good news. They will have to be stainless. Certainly would save a lot of work. Below is my first bypass lever and bracket. The lever is stainless cut out of a large stainless rod (à la Roger) on the Tormach and then parted off in the lathe. All I need now is a nice stainless nut, which has the washer as part of the nut (see the picture above of the full-size) - so I will try and do that in the Tormach as you showed me when I visited you. Bypass Lever and bracket S by ed cloutman, on Flickr
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Post by Roger on Apr 12, 2019 12:49:03 GMT
Here is the proper nut to hold the lever on. It was machined on the Tormach in one pass at full depth and spotted for the hole in the centre. It was drilled and threaded 8BA in the lathe, the chamfer added and then parted off. The hexagon is 9BA. I love this CNC machine - it makes a job like this so simple and quick. I used to file things like this by hand, but my eyes are just not good enough now. Bypass lever nut by ed cloutman, on Flickr Hi Ed, I'm not seeing that picture, it's showing as page not found
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Post by terrier060 on Apr 12, 2019 12:53:05 GMT
Here is the proper nut to hold the lever on. It was machined on the Tormach in one pass at full depth and spotted for the hole in the centre. It was drilled and threaded 8BA in the lathe, the chamfer added and then parted off. The hexagon is 9BA. I love this CNC machine - it makes a job like this so simple and quick. I used to file things like this by hand, but my eyes are just not good enough now. To centre the workpiece I held it in a collet in the spindle, then lowered it into the four-jaw chuck with the table set to 0,0 on the X and Y axes. I then gently closed the jaws until they were just touching the workpiece and then progressively tightened them. It worked well. The Tormach is great at centering. I can switch it off and next day switch on, reference each of the axes but do not zero them. I can then continue machining where I left off the day before. Bypass lever nut by ed cloutman, on Flickr
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