Member postings for Muzzer

I didn't, to be honest. I saw these being used on some of the professional support forums for the likes of Solidworks and Solid Edge. Then I saw that they were only $100 and that pretty much did it. It only has 2 buttons (which you don't even need to use) and the rest is just the little black tower thing. Push, pull, twist and nudge, all in one.

Interestingly, our PCB layout boys at work use them (Altium) but our mech engineers don't (Solidworks). Dunno if there is a lesson to be learnt but so far it seems to be quite a useful tool. The mechies are probably just stuck in their ways! Without it I have to keep interrupting feature edits to pan, zoom or rotate. Now I can manipulate the model with my left hand without interrupting the work flow that's happening with my right (normal mouse).

It also integrates with other applications such as Google Earth, so you can fly about like a bird - should the urge grab you. There are drivers for most of the obvious 3D applications as well as some training applets. Highly recommended.

Merry

Some of the DIY printers are not surprisingly of very indifferent quality and capability but the semi-professional machines that Andrew Johnston and John Stevenson have bought are clearly at the top end of the range. Look at the examples they have reeled off and I think you'd agree they are better than "very poor", although it depends what you are looking for.

Andrew's herring bone gear set actually worked without having to be taken apart and cleaned up and the parts John made are very functional - and a pretty reasonable finish. I don't think these boys are planning on making clock parts so let's not get too sniffy. It's only a few years ago that machines costing an order of magnitude more were making parts that looked as if they were made from Shredded Wheat.

I wouldn't put people off having a go at 3D CAD. It may be a bit of a learning curve but once you have learned the basics of the application and done a few of the tutorials you are half way there. Bear in mind that most of us already do the other part ie visualising, designing and drawing up our parts ahead of making them. There is quite a choice of CAD applications out there, so if you try one out on a limited duration trial and don't like it you can always try another one. It's horses for courses.

The basic version of Alibre is now called "Cubify" with exactly this market in mind, as they also own a 3D printer company. It's actually reasonably cheap and has a surprisingly full set of features in common with the full professional version. If you like it and want to use it beyond 3D printing (ie save to different file formats etc), you can simply upgrade to the full package by buying a bigger licence key. Personally I didn't but that was for other reasons. However, if you are thinking of driving one of these 3D printers, it makes a lot of sense to take a look. You never know where it might take you...

Merry

Nigel

Yes, I looked at this when I was figuring out what was possible and what was required. As you doubtless know, "proper" BT30 tooling is capable of handling high power and very high speeds (over 15krpm seems not unheard of). However, this is a venerable, fairly lightweight BP clone which has limited capability and will only be using fairly small tooling of barely adequate quality at modest speeds. I'm certainly not pretending that this would be suitable for any industrial applications on the likes of the machinery you mention.

I did some very rough fag packet calculations to estimate what force I was applying through the drawbars and that came out at around the 50-70kg mark ie not far off the weight of a smallish adult. Requires a blow or two from the mallet to remove it. My die spring allegedly has a spring rate of around 150lb/in in old (ie USA) units, so with an inch or so of preload should be similar to what I was applying manually, although with little to prevent the tool pulling out under load beyond that.

The "Mach-1" quick change system for R8 tooling is the only one I could find on sale that still uses this ball and ramp concept, probably for the reasons you give. However, there simply isn't room in there for the kind of positive locking mechanism normally found in modern BT30-equipped industrial machines and I wouldn't have the capability to attempt the components required anyway. The Mach-1 claims a 600lb preload from a 1" x 4" die spring, so it's providing more pull force which is fair enough, given the applications they claim it's good for.

I agree with your concern about whether or not I have sufficient preload and this is something I need to look at more closely. I noted that I can obtain a "heavy duty" version from the same supplier which has twice the spring rate and also get a shorter version which will further increase that. Now that I seem to have constructed it and it appears to work, I need to convince myself that it is fit for purpose.

Thanks for your comments and experience!

Muzzer

Crimbo present to self finally arrived today. "SpaceNavigator" 3D "mouse" from 3DConnexion. Cost $100 (60 quid) and allows pan, tilt, zoom etc from one control in 3D CAD. Very nice. You lift, turn and push the knob gently, trying not to induce too many inputs simultaneously(!) Sounds simple enough....

The biggest challenge will be getting my abused, aging and atrophied brain to handle all the degrees of control at once. Something new to swear at, then!

Merry

Finished setting up and testing a quick change tooling system for my NMTB30 milling machine. I've created a little photo story in another post on the ME/MEW forum: **LINK**

Quite pleased that it seems to work!

Merry

This is the only photo of the assembled clamp assembly. Not much to see finally - space was limited.

I realised quite early on that in order to make enough space in the spindle cavity for the mechanism, I would need to shorten the (non-functional) parallel shanks on each tool holder to accept the pull stud. I ended up removing about 10mm from the length. I heated the shanks up to red heat to make them machinable without affecting the main taper. I can still use the original drawbar(s) if I need to go back.

I obtained a 4" long die spring with 1/2" bore that seemed about right for the application. My estimation of the axial force I typically applied with the existing drawbars suggested that the spring rate should be of the correct order to allow a sensible adjustment of preload.

The drawbar has an adjustable tapered bronze nut at the top end that butts up against a hard stop. This allows the spring to be compressed when you force the quill up against it through the last 5mm or so of return travel, releasing the pull stud.

With the component parts hardened and tempered and the parts assembled, I checked that releasing the compression spring before the pull stud was fully inserted did not result in broken parts. This worst case condition puts a fair stress on the collar in particular but it and the studs seem able to tolerate it.

I can now change tooling in the time it takes to drop one tool holder out and insert another, which is of the order of a second or so. That's a significant improvement on the endless palaver with the spanner, mallet and swapping drawbars which took nearer a minute. I will have to find something else to swear at now.

That was my metal therapy for the Xmas break! HNY to everyone.

Merry

Once I`d acquired some ball bearings from a local bike shop and a few 1/8" ball-ended slot drills, I had everything I needed to get started.

The stepped outside profile and M10 thread was pretty straightforward using carbide indexable tooling and M10 die.

Boring the holes for the ball bearings required precise setup in the milling machine. The holes were cut with a ball-ended slot drill such that the 3.2mm diameter ball only emerges 0.9mm into the central bore at full engagement, otherwise the balls would fall out between tool changes. I set up the work individually for each hole using a center finder and the DRO and carefully bored to the precise depth. The cutter was slightly under size relative to the ball, so I moved the cutter to give an additional 0.1mm in all 4 X and Y directions. This worked well - the balls are free to move but aren't in any danger of falling out.

The pull stud had to be machined ``backwards`` ie with the large M10 or M12 thread at the tailstock end. I don`t have an M12 die any more(!), so had to set up my (imperial) Bantam to cut the M12 x 1.75 thread. Once you start cutting with this setup, you mustn`t disengage the half nuts. Then I turned the head of the stud using a parting tool and 1.6mm radius tool, before parting it off.

The final part of the core assembly is the closing collar. I machined this in the lathe using a small HSS boring bar and achieved a pleasing finish and accuracy. The groove on the outside is to house an o-ring. This provides some drag on the collar against the bore of the machine spindle to open and close the mechanism as the draw bar moves up and down against the spring. It seems to work well.

My used Taiwanese Bridgeport clone milling machine has a NMTB30 taper for the spindle tooling. As I now live in Canada, this has been a bit of a hassle, since almost all tooling for these machines is R8 here. Tooling in general in North America is very expensive - it`s either locally made and expensive or it`s imported (Chinese or Indian, the usual suspects) with the price hiked up so it costs about twice as much as it would in the UK. I ended up buying most of my spindle tooling from the UK and was a lot better off even after duty and shipping. However, I now have a mixture of M10 and M12 threaded NMTB tooling.

The NMTB30 has an ISO30 taper and a short parallel shank with either an M10 or M12 internal thread for a drawbar. I've become rather tired of having to swap over the drawbar from M10 to M12 each time I want to change from the M10 threaded drill chuck (drills, centre finder etc) to the M12 threaded collet chuck (milling cutters etc), so I started to think about quick change systems.

The normal solution in N America is a power drawbar. This is basically an air powered impact driver mounted on top of the head. There is also an air solenoid that engages the impact driver with the top of the spindle before it starts to turn. This presumably works pretty well with R8 tooling but wouldn't be quite so effective with the NMTB and MT tooling which requires more encouragement to eject. It would also require a compressed air supply which I don't currently plan on installing.

"Proper" quick change tooling used on CNC machines uses a pull stud mounted on each of the tools and a claw device that positively locks onto the stud and pulls it into the spindle (usually against some form of taper). There are also other systems that use a ball and ramp system rather like the concept you see used in industrial and garden hose couplings. Either way, these systems generally require a sprung draw bar to retain the tooling and some means of compression / ejection. Some quick patent searches come up with the obvious solutions, mostly expired long ago. I wasn't going to be inventing anything particularly novel here.

I didn't fancy the impact driver approach , either air or electrical. It just sounded too messy and probably not appropriate for a fixed taper. The industrial pull stud equivalent of my NMTB system (called BT30 etc) requires space inside the spindle for the pull stud gubbins that simply doesn't exisit in my machine. I measured up the (tiny) space available in my spindle and got scheming (and modelling).

The parallel shank on the NMTB30 doesn't actually contact the spindle bore, so apart from housing the M10/M12 thread it has no functional purpose in my setup. I could chop much of it off as long as there is enough thread remaining in the (hardened) body to accept a pull stud. By doing so, I would have a cavity of about 17mm diameter and around 30mm length in which to accommodate some gubbins of my own device.

Here's what I came up with. A fairly conventional pull stud (to my own dimensions, by necessity), a mating socket with four captive 1/8" ball bearings, a sliding collar with a ramp to drive the balls into the groove in the pull stud and an o-ring to cause the collar to drag within the spindle cavity. Beyond that, a draw bar would extend up above the head. This would have a compression spring to keep the tooling engaged and an end stop and bearing bearing so that the draw bar and spring could be compressed by raising the spindle against it, to allow tool removal. Sounds simple enough but would require some critical machining. My skills are closer to the agricultural engineer than the watchmaker, so this would be a challenge...

Edited By Muzzer on 02/01/2014 22:38:31

Edited By Muzzer on 02/01/2014 22:38:46

Edited By Muzzer on 02/01/2014 22:39:04

This is the same make as the one I bought during a visit to Shenzhen, China recently. Like you, I've found it to be fine and not bad value for money at all. The instruction manual is worth the cost alone - makes Xmas cracker jokes look lame! I ended up downloading manuals from other manufacturers - they are mostly very similar in operation.

There are some pictures in my albums under "DRO fitting".

I now have 2 Z scales - one on the quill and one on the knee. I actually find the quill one to be more useful.

Muzzer

Edited By Muzzer on 02/01/2014 04:17:18

Edited By Muzzer on 02/01/2014 04:20:26

Never done it myself but apparently a common technique is to use a Dremel-type device to route out the copper from the PCB surface. This avoids the need for the nasty chemicals altogether and I suspect you may have problems getting a consistent flow of ink if you are using Dalo pens (from memory - do you still use them?).

Presumably it doesn't much matter how you cut the thing as long as you don't make a complete arse of it. You will need to bore the central bearing afterwards anyway, so you could easily skim both sawn faces in the milling machine which would be a very simple task and give a clean mating pair. As suggested, it may make sense to drill (and tap) the bolt holes beforehand. Once bolted back together, you can bore out the centre and Bob's your auntie.

Make sure you buy a 3-phase motor that is rated for "220V 3-phase" (most probably in "delta" connection, for what it's worth). You only have 3 wires to connect up and it doesn't matter which way you connect them - if it spins the wrong way you can simply swap any 2 of the wires over. The motors originally fitted to these machines are Xmas cracker quality, so fitting a normal 3-phase motor may also bring the benefit of a quieter experience!

There are literally dozens of VFD manufacturers to choose from. It may be worth asking around to identify something that is very straightforward to set up and possibly even work out of the box if you aren't confident about configuring one of these.

Merry

Edited By Muzzer on 27/12/2013 17:28:23

Like Ian SC, I made my own (using a 24V window winder in my case). If you go the DIY route, there are pics of my feed in my album here **LINK** . A variable voltage power supply (0-15V for a 12V motor) is helpful, as it allows you to change the feed rate to suit the job.

I now have a Bridgeport clone so haven't touched this machine for ages. I do remember though that there are power feeds available for the X direction but they cost almost as much as the machine was worth, hence the DIY solution. Depends how rich you are feeling!

If you do a Google search on "power feed mill drill" you will see that generally, feeds for this kind of machine are based on the power feed units that were developed for Bridgeport type machines, modified (fitted on their side) to fit onto the ubiquitous mill drill. So if anything they are more expensive than the original Bridgeport part. they are derived from.

I see that Chronos sell Vertex power feeds (decent Taiwanese brand). For the std Bridgeport application they seem to be about 240 pounds. For the mill drill, they are 270 pounds which sounds about right. **LINK**

Merry

Ferrites are essentially ceramics as far as machining goes. They are machinable but the correct process to apply is grinding or abrasive cutting. Imagine you are machining a lump of glass and you won't go far wrong. Parts for volume production are sintered and fired, during which time they shrink a bit, then any critical faces are machined flat. For prototype parts, samples can be machined up from solids but it's not as simple as turning or milling.

However, if you are thinking of producing magnets rather than magnetic components (transformers, inductors etc), steel and similar magnetic alloys would be a lot more convenient to machine, as noted. Generally, magnets are magnetised after they have been physically made, whether ferrite, neodymium, steel etc. This requires some pretty challenging equipment. Apart from the difficulties machining magnetic material (swarf clearance?!), the magnetism may suffer during machining, especially if they get hot. And the original alignment of the magnetic field may not be exactly what you are hoping for in the final part.

If you are thinking of forming a custom magnetic part, why not buy some std neodymium magnets such as buttons or cubes and then machine up some magnetic pole pieces to sandwich around them to direct the flux where you want it? Although the maximum flux density of steel is not as impressive as the likes of neodymium, you can still develop a fairly decent field with steel as a conductive medium.

I bought a selection of impressive magnets from here **LINK** some years back although there must be many more suppliers, not least ebay.

Merry

Yes, you can't really "supercharge" a 2-stroke even with exhaust valves and proper injection. The blowers and turbochargers are primarily to ensure scavenging. However, when you have a V engine like this, you aren't going to get any effective crankcase pressure when you need it, so the transfer ports aren't going to do much for you. The use of a supercharger (scavenge pump?) is probably a sensible choice here, given that Dean is aiming to get this impressive beast working. At least there is a decent chance of the cylinders getting some mixture........as he explained back on the 8th.

Is this a CI (diesel) or will it have spark plugs? That's a lot of parts either way! Good luck, lots of people watching and wishing you well - no pressure, then!! It'll make a fantastic noise / smell....

Edited By Muzzer on 21/12/2013 18:28:33

Go back and look. Actually "S**tbay and S**tpal". Perhaps I spell "slow" differently?

As I said, nothing personal and I'm not offended either, just seems rather childish. Ketan seems like a decent chap and Arc a great business. Pity to risk offending potential customers.

God alone knows how you managed to keep a semi constant feed going there!

Here's a quick example of parting off with power feed just now:

**LINK**

After some experimentation which was thankfully free of rubber pants moments, I found that 300rpm and 5 thou per rev was a very safe condition. I could get up to 4-500rpm but that seemed to be the limit of unconditional stability tonight. Turning up the speed as the tool progressed sped up the overall process a bit but really made no big difference, so hardly worth the extra focus required.

Generally, speeds around and above 1000 rpm didn't seem to work consistently - once you go over the stability boundary you have to stop and bring the speed right down again.

Lovely clean finish and the swarf generation is so quiet and consistent it appears stationary (careful!). I expect I'd need to get the speed up over 1000rpm to get the swarf to break up, so that probably isn't about to happen.

I certainly couldn't produce this kind of consistency by hand.

Merry

The moment of truth finally arrived, so I ventured out to the garage wearing my best rubber underpants. Who knew what could happen?

The first attempt wasn't entirely fulfilling. I pussyfooted about with what I calculated to be 2.3 thou per rev and about 400rpm with no coolant. I also discovered later that I was the best part of 10 thou below centre height. This resulted in several noisy but successful partings - but the surface finish was pretty nasty (little bits seemed to be welded to the bar surface) and there were some nasty grumbling noises going on. Not good. This didn't feel like the experience I'd been hoping for.

So after some researching and thinking and advice, I changed tactics. I checked everything was nicely nipped up, the tool was centred over the cross slide and a couple of thou above centre height and went for 5 thou per rev and 500rpm with flooded coolant, stopping half way in and upping the speed to 1000rpm (this was a 1" dia mild steel bar). Excellent result - no chatter or judder, nice clean surface finish, "approved" swarf and no nasty grumbling or snatching. Callooh, callay!

The last photo shows a whole parting event in swarf. Started out as a long, tight spiral, then progressed to longer curls as the groove deepened, then ended up with a series of watch springs that were generated within the groove. A bit unnerving watching these build up before finally coming free but the swarf is narrower than the groove due to the design of the chip breaker so isn't likely(?!) to jam. I found the swarf to be typically about 7-8 thou narrower than the 3mm nominal tool insert.

Its probably a bit early to start believing this is the end of the story but it seems to vindicate the idea that you need to steel(!) yourself and go all in with the recommended feeds and speeds. In the interests of science and a more predictable outcome in future events, I should explore the limits of chatter-free operation. It seems that there are typically regions of instability where combinations of feed rate and cutting speed result in chatter. This will depend on my machine as well as the dimensions and material of the workpiece.

Merry

Doesn't really matter what electric heater you use, they are all exactly 100% efficient. So unless you do something clever like point a radiant heater directly at the window, it'll produce the same final temperature as a fan or convection heater in the end. However, if you point it at something like a machine tool or a human body, it will warm that up to a higher temperature than the local ambient. I like to use a thermostatic fan heater myself - they can often be turned right down to prevent frost.

Occasionally you see the odd manufacturer claiming that their electric heater is "more efficient". Unfortunately the laws of physics generally prevent that possibility. Unless you are in the USA, where that kind of claim still seems to be acceptable!

Merry