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Member postings for John Hinkley

Here is a list of all the postings John Hinkley has made in our forums. Click on a thread name to jump to the thread.

Thread: An explanation of CNC machining terms
10/04/2021 22:44:09

Thank you for the lead, Ian. I'll look out for that book.

John

10/04/2021 17:18:54

Oh. And just one last thing. As the 'For Sale' ads aren't updating on the side panel again, my engraving machine is up for sale - so I'll give it a sneaky plug here.

John

10/04/2021 17:14:04

That's what I'd hoped. Fun times ahead, I think. Should keep me occupied for the foreseeable future!

John

10/04/2021 12:51:48

Jason,

Thanks, again. I have downloaded Fusion once more and will have a look at those videos before diving in. I have a few stl files from Alibre Atom with which I can experiment. I got MeshCAM Pro upgrade free, additional to the router kit, so I'll probably persevere with that to start with, but it's always good to have another string to my bow.

John

P.S. I'm hoping to be able to use the router to replace my pantograph engraving machine, too, as it will need to take up the space it currently resides in.

edited to include post scriptum

Edited By John Hinkley on 10/04/2021 12:54:42

Edited By John Hinkley on 10/04/2021 12:55:13

10/04/2021 11:22:11

Emgee, thanks for the info re. Fusion. I hoped that I would be able to use it like that. Maybe I'll download Fusion later and have a play.

David. Thanks for the pointer. When the Shapeoko arrives and I've assembled it, I'll be in a better position to direct particular queries towards Rob, rather than the more general questions I have now.

All good stuff. Thanks, chaps.

John

10/04/2021 10:43:30

Thanks, Jason. That's at least given me an inkling. I'm reluctant to start again with Fusion360, having got to grips with Alibre Atom. Is the CAM section of Fusion a separate entity or is it reliant on the Fusion CAD program to function? I particularly don't like the 'cloud' element of Fusion.

John

10/04/2021 10:08:12

Due to a lucky break, I shall shortly be dipping a toe or two into the water with respect to CNC machining. Specifically using a router table. I have some initial plans to use it to practice some shape forming in wood, but hope to progress swiftly to production of aluminium parts. The router table that I will be using has been demonstrated to cope adequately with aluminium and just last night, I watched a couple of videos of one being used on hot-rolled steel and even stainless steel. So, please don't tell me it can't be done!

To get to the point of this posting at last, I am a little mystified by some of the terms used in the G-Code generating software (I'm using MeshCAM Pro) and was hoping that someone on here could recommend a book or other documentation which will explain, in simple terms, what they mean. I'm thinking of, for example, 'roughing toolpath' and 'unified finishing toolpath'. I can hazard a guess as to what they mean, but guessing isn't part of the game in CNC, is it?

I have Googled, of course, and all I get is references to the software manufacturer's documents, which only describe 'how tos' not 'why-tos'. Either that, or specific queries posted on various CNC forums, receive answers that refer the enquirer to web pages that are no longer available.

Any help would be appreciated.

John

Thread: Involute tooth depth
07/04/2021 19:06:14
Posted by Pete Rimmer on 07/04/2021 17:18:02:

John, it's actually half of that.

Regards

Pete

Well spotted, Pete. Should have been obvious, really. I thouht it was a bit deep at the time, but failed to apply what little common sense I have left!

John

07/04/2021 15:57:58

David,

To answer your question directly, I used my go to gear generator software. It gave the following result for the quoted gear:

GearDXF screeenshot

In case it's not too easy to see from the above screenshot, the depth of cut works out as 65.0 - 60.5mm = 4.5mm. Or if you prefer, 0.177in.

John

Thread: A Radio Oddity
03/04/2021 09:42:52

Nigel,

Perhaps you could connect it to a Theremin device to produce a sound/light show?

John

Thread: CNC - What's the Problem?
01/04/2021 11:44:49

I have been having a "play" with some CNC software in the last couple of weeks and even as a complete novice, with resppect to cnc, can produce simulated toolpaths for a simple 3D drawing and subsequently the gcode to make the part, The software flow goes like this:

I designed part in Alibre 3D - loaded stl file into Meshcam V8 and did the necessary to generate the toolpaths - pressed the save gcode button.

This is the 3D part:

3d conrod blank

And the resultant toolpath looks like this:

Roughing toolpath

This is for a roughing pass and doesn't machine the top surface. It took a number of experimental tries but the gcode is only a mouse click away and further toolpath generation will produce a finishing cut which will do all the final machining. The two holes where the big and little end bores go are intended to be for mounting to a machining fixture so that the blank can be flipped and a pocket machining run will carve out the other relief and recess.

I found that the main problem I had was learning all the new (to me) terminology.

I realise that this doesn't add much to the original query, but does illustrate that, with the right tools, control of a machine is within the grasp of most people.

John

 

Edited By John Hinkley on 01/04/2021 11:46:26

Thread: Advice acquiring single phase motor for Elliott Pillar Drill
01/04/2021 11:10:49

Kevin,

There's no need to worry about boring pulleys or reducing shaft sizes on whichever motor you fit. I have successfully used pulleys with the Taperlock system, like these. Having said that, I'd go with the majority and recommend a VFD for the versatility and control it will give.

John

Thread: Armadeal lathe
30/03/2021 16:08:25

Jonathan,

I suspect this is a typo. I've certainly never heard of the expression. If you could expand a little by quoting it in context, that may allow us to suggest what the enquirer is on about.

Have you tried responding to the query and asking for clarification?

John

Thread: Excellent Chinese Chuck
28/03/2021 12:10:50
Posted by Dave Halford on 28/03/2021 11:48:35:

Isn't the 6 jaw intended for grinder applications?

My understanding is that six-jaw chucks are more suitable for holding thin-walled tube, having less crushing force applied per jaw for a given grip. That's not what I got it for, though. I just thought it looked pretty cool, to use the modern idiom, and it holds the size of material that I generally use and hopefully more accurately. But then I didn't know any better. Like I've said before in many posts, I'm not a trained engineer, just a bloke who potters about in a "shed". "Playing" my wife says.

John

28/03/2021 11:35:36
Posted by Brian Wood on 28/03/2021 10:16:23:

Before I duck down and take cover below the parapet, could any of you gentlemen who are satisfied with these chucks and praise them for quality and finish tell me if the jaws are hardened or not.

Being a sceptic, I find it hard to believe they are.

Regards

Brian

Brian,

I've just nipped out to the workshop and tried a file on my six-jaw chuck. Result: the file skids off without leaving a mark, I'm relieved to say. So, my assumption is that, yes, they are hardened, or at least, mine are.

John

You can come out from beneath the parapet now.

Thread: Replacement Chuck for Hobbymat MD65
28/03/2021 10:09:57

Keith,

I downloaded the user's manual for your machine and looking at the parts diagrams, it would appear that the lathe spindle has a flanged nose to which the standard chuck is attached. But then you'll know that, having taken it all apart to refurbish it. Unless you are going to replace like-for-like, I guess that you will have accept that you will need to undertake a certain amount of machining to ensure any replacement - especially larger - chuck is to fit well and correctly. I wouldn't personally go any larger than 100mm diameter on a lathe of Hobbymat size. (My lathe had a 550W motor fitted originally and really struggled with reasonable depths of cut and feed rates and was fitted with 125mm diameter chucks.)

If you decide to go bigger, you could do worse than investigate the possibility of modifying one of these from ArcEuroTrade. Have a look at these chucks, too, from the same source. Note the comments on the latter page:

" Note: Standard Mini Lathes have an 80mm chuck fitted on a spindle flange with a register of 55mm (dimension H). Some Mini Lathes have a 100mm chuck fitted on a spindle flange with a register of 72mm."

Good luck and welcome to the forum,

John

Thread: Excellent Chinese Chuck
27/03/2021 16:19:10

I bought a six-jaw Sanou chuck last year. It was probably from the same UK seller as yours Chris, by the sound of it. I was originally attracted by the price, too - £99 inclusive of VAT and delivery. Its only downside is that it will not grip very small or very large diameter workpieces, for which I swap it out for either a 3- or 4-jaw, but nevertheless spends 99% of the time mounted on my lathe. Can't fault the finish or accuracy within the limits of my measuring equipment.

Sanou six-jaw chuck

John

Thread: What's the general consensus please?
26/03/2021 08:10:16

I don't have a pillar drill - there simply isn't enough space in my garage/workshop. I find that if Ihave a job which entails drilling and milling, by writing down a work-flow plan, I can usually do all the necessary procedures in one workpiece set-up. All that is required is to change drills for end mills or vice versa. Time consuming, but I'm not earning a living from it - thank goodness, otherwise I'd be starving!

My advice: stop dithering, ditch the drill if space is tihat tight and order the mill.

John

Thread: Flat bottomed hole with a boring bar - technique?
18/03/2021 09:19:58

Posted by Dr_GMJN

I've got a couple of those Sandvik tools, and a holder (Coroturn XS CXS-A10-05). The inserts for it have a chamfered end - I could have sworn mine were for internal threading. Perhaps they are, but you can get also boring bar inserts for them. I wonder what the difference is? Do you happen to know what catalogue # your small Sandvik boring bar is?

I can't find the original listing as I purchased the boring tool a number of years ago, but this, from the Cormorant range has the same tip shape.

Sandvik boring tools

The one on the left is the same profile as mine and will produce a flat-bottomed hole.

John

17/03/2021 17:18:44

I missed the bit about the through hole, Jason. Must remember to engage eyes before typing!

John

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