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View Full Version : How tricky would this be to machine? I guess a Triac is not up to the job!



suesi34e
12-06-2016, 02:09 AM
Hi guys this a 316 stainless part in that it fits onto a 25.4stainless tube. I would like to have them bored out to 28.58 or there abouts tofit on a larger diameter tube, it looks like there would be enough meat leftbut I wonder how tricky a job it would be to do. I need to do 14 of them ifanyone has any ideas or advice I would welcome it. I do not know where to start!
Many thanks 18668
Steve

mekanik
12-06-2016, 11:07 AM
Hi Steve
Do you have a faceplate for your lathe ?
Mike

Neale
12-06-2016, 11:30 AM
Looking at the dimensions you give and trying to scale off the photograph, you are going to leave around 0.8mm wall thickness at the hinge point, or you are going to need to move the axis of the new bore slightly sideways to leave a bit more metal. Is that going to be strong enough for your application? If I were doing this, I might consider a faceplate (if the workpiece is a good shape for clamping) or maybe even look at holding it in a 4-jaw, although I don't know if you could get a good enough hold without marking or distorting the work, especially as the wall thickness reduces. Be interesting to hear how the professionals would tackle it!

suesi34e
12-06-2016, 01:03 PM
Hi Steve
Do you have a faceplate for your lathe ?
Mike

Hi Mike, thank you for the thought but I don't have a faceplate or lathe! I only have my Triac. I should have said I was thinking of farming the job out once I know what direction to go it or not to go in!
Many thanks
Steve

suesi34e
12-06-2016, 01:10 PM
Hi Neale,
Tar very much for you thougths. Yes I think moving away from the hinge would be good, there is little stress though. 14 of them are just going to hold a plastic panel, that is if this plan wins with my few options for the job. I don't have a lathe so if I see the best way to do it I will farm it out if that is the route I go.
Many thanks
Steve

spluppit
12-06-2016, 02:43 PM
Personally i would look at away to mill it if possible. Reason is: its hard to define how that clamp was manufactured in the first place. There is a chance it could drop forged and if it is, it will be full of strength in every direction and 'can' be as tough as it gets to machine especially in 316. If its cast it may be better. Like all things like this, you will only know how good or bad it is when you start to machine.

I would steer away from boring due to intermittent cuts, if possible but not essential. Milling cutters are nice and strong and the intermittent cut wont effect a milling cutter. Images can be a bit deceptive but it looks like the rad on the profile does not match the rad center on the inch hole (on the top at least) and it may be very hard to get right in a 4 jaw if even possible. Then you have to repeat 14 times. You could fix it to a separate fixture plate held in a 3 or 4 jaw then calculate the center and put some strategically places dowels to locate it central and use some small clamps, this way you eliminate varying set ups each time, or a variation on this theme would work. A few options to chose from on that theme. In the same breath a plate method could be used to also mill it. The other option if a part dxf is available is to machine the outer profile into soft milling jaws then machine, This would be made a lot easier if the part dxf or similar was available and also cad/cam would help a lot and speed up the process going the soft jaw route. This is how i would approach it as someone in the trade so i don't end up with one launched in my face..... which would undoubtedly hurt a fair bit.

This is an example of a fixture type set up to make life easy.

1866918670

Lee Roberts
12-06-2016, 05:59 PM
Here is an example of when a mini pallet maybe of better use:

https://youtu.be/b2qKy43tJcY

.Me

magicniner
12-06-2016, 09:59 PM
Have you considered machining a pair of aluminium soft jaws for your mill vice? It's a great way to accurately hold oddly shaped parts in the mill.
Machine a pocket across the two jaws that comfortably accepts and supports the part, use a parallel as a spacer to allow you to clamp the vice up tightly with the right gap whilst machining the soft jaws.

- Nick

suesi34e
13-06-2016, 01:07 AM
Hi Spluppit,
Many thanks for such a detailed reply and the attached photos. Having read your reply and having thougth about what you have said I see you have raised some important points and they are of help. I have a good bit to think about!
Many thanks
Steve

suesi34e
13-06-2016, 01:08 AM
Thanks for the link Lee, I have watched the video he is a good guy.
Steve

suesi34e
13-06-2016, 01:13 AM
Hi Nick
Thank you for your thoughts. I would like to try and make some aluminium soft jaws like you mention for a job sometime bet it is a great way of holding some parts up there with the best way I would think. I just think for this case the 316 would be a tall order for my machine. I will soon be making some soft jaws for job or another.
Many thanks
Steve

Neale
13-06-2016, 09:13 AM
One clear message to take from that video, something that isn't always apparent to someone starting working with machine tools of any kind, is that you can often spend much longer making a fixture and setting up than you do machining. However, that fixture and set-up time are the difference between a successful job and one that flies out of the chuck or ends up with gouges across the workpiece where it slipped in the machine vice. Of course, a big lathe and 12" 6-jaw chuck also help!

cropwell
13-06-2016, 05:18 PM
Here is an example of when a mini pallet maybe of better use:

https://youtu.be/b2qKy43tJcY

.Me
I like the idea, but it is a boring (not a deliberate pun) video. I would bore a big hole in the pallet and use a bullnose in the tailstock to position and hold the workpiece while you clamp it down. You can then check the original hole in the workpiece is central with a dial guage, if it matters that much.
Rob

mekanik
13-06-2016, 09:15 PM
Guys
Steve doesn't have a lathe, i asked if he had a faceplate so that i could explain a technique.

suesi34e
13-06-2016, 11:59 PM
Hi Neale, thank you for your thoughts. I see what your saying 100% I have never made the fixture type in question but lots along similar lines.
Many thanks
Steve

suesi34e
14-06-2016, 12:03 AM
Hi Rob
I hope your doing OK there mate. Thak you for the thoughts Rob. Perhaps one day I will get a lathe and I look forward to that day!
All the best
Steve

suesi34e
14-06-2016, 12:05 AM
Thanks mekanik, perhaps one day I will get a lathe. That would cause another project extending the workshop!
Many thanks
Steve

magicniner
14-06-2016, 12:17 PM
I think your Triac should manage it, my little benchtop CNC would, the trick is to get your tooling, feeds & speeds, DOC and cutting lube right.

- Nick

suesi34e
14-06-2016, 08:33 PM
I think your Triac should manage it, my little benchtop CNC would, the trick is to get your tooling, feeds & speeds, DOC and cutting lube right.

- Nick

Hi Nick, thank you for the thoughts. I think I would get myself into a whole world of hurt with 316. I am don't know much at all about CNCing and nothing when it comes to 316. I have made some parts out of plastic that worked well but I harldy ever get to use my machine and does'nt help with getting to grips with things. Like you say you would need to know about the tooling feed and speeds and I could write what I know on the back of a postage stamp!
Many thanks
Steve

magicniner
14-06-2016, 11:21 PM
Steve,
316 isn't anything like as scary as a lot of people make out ;-)

suesi34e
15-06-2016, 03:29 PM
Hi magicniner, thanks for the reasurance I hope to get a little lathe oneday and try my hand at 316 on that.
Many thanks
Steve

magicniner
15-06-2016, 06:11 PM
Steve, With carbide tooling on a lathe 316 is quite sweet to work with, I don't know why people get steamed up about it ;-) - Nick