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Member postings for Muzzer

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

Thread: Stepper Motor basics
01/09/2018 17:46:33

As Martin suggests, closed loop steppers provide a lot of beneficial features. If you search for "integrated closed loop stepper" you will see that there are now quite a few clones of the Leadshine "Integrated Easy Servo" products around now.

For under £100 you get a combined stepper motor, encoder and driver. Just provide the PSU (~36VDC) and the step / direction signals and Bob's your auntie. You can even program parameters such as how many steps error will trigger the "out of position" output and the PID terms through their software GUI thing.

Nice thing about closed loop is that they will recover position within reason. Difficult to see why you would go any other route if you plan to use a stepper rather than a servo.


Thread: What did you do Today 2018
29/08/2018 20:21:31

Neil - when are you going to fix the "for sale" panel (again)??

It's been stuck at the misnamed "colchester student roundhead" entry for ages now (weeks?). Thought you'd fixed it last time?


Thread: Yet another parting tool question...
29/08/2018 19:39:39
Posted by Niels Abildgaard on 29/08/2018 17:57:22:

We are close to the final part off solution.

A firm is selling a pirate blade+ 10 iscar 3 mm inserts and the block.


If manufacturer of blade can be persuaded to make one end suitable for TAG N1.4J inserts we are in safe heaven.

You can get a genuine Iscar version for less, including 10 inserts. Funny what the Germans will pay out for - at that price, they are "removing yellow fluid". The toolholder for the blade is an industry standard jobbie and they are available for under £50.

I'm very tempted. However, I'd also have to get the non-ferrous tips too, for cutting loominum.

Is Zoro another instance of Cromwell (Grainger)? The websites look remarkably similar, hold similar lines (they also stock Iscar tooling) and some of the page addresses contain the word "cromwell". Not sure how they are related but they don't admit to any connection.


28/08/2018 19:57:24
Posted by Neil Wyatt on 27/08/2018 16:37:56:
Choice between Cutwel prices (min £15 delivery) and APT a minimum order quantity of 10 so over £50 with VAT and shipping.

Might pop in next time I'm near a Cutwel as none of the hobby suppliers seem to do uncoated, not even JB.


Possibly one of those things to keep an eye open for. Each month, they do special offers that often include "buy 10 inserts, get free body etc". Or sometimes it's just a tasty price reduction. Pretty sure they did one on the KGT or MGT series not so long ago, which may explain why I have a few of them. This month's offers are here.

If you are in the Cleckhuddersfax area, it's possibly worth calling in, although the postal service is generally pretty quick and reliable. For small orders, they use Royal Mail at £3-4 or so. Free P&P for over £100, IIRC.


27/08/2018 14:54:06

Not sure if the Korloy Sawman inserts are 100% compatible with the industry standard "GTN" pattern but either way, Cutwel do the uncoated "H01" grade for cutting loominum. Flood coolant seems to help with parting loominum if you don't have the right insert.

For profile, sideways cutting, grooving and shallow parting off, I use the MGT and KGT grooving systems. As pointed out, these inserts have cutting edges on the sides as well as the end. And I see APT stock the polished, uncoated version at £4.

One way to get yourself a serious crash during parting is to allow the work to slip in the chuck. That doesn't end well if you are parting off with power feed, which is the best way to make consistent but decent progress. It seems to bugger the holder as well as the insert...


Edited By Muzzer on 27/08/2018 14:57:11

Thread: Facemill Hammering, solved
27/08/2018 14:36:49

Not sure what you mean by "tangent" to the work. The path of the cutter is essentially a circle. The resulting work / cutting locus is generally a rectangular shape. Do you mean the cutter should be placed centrally and it should be smaller diameter than the workpiece, so that it makes a semicircular cut? That means a 100% engagement, which few people seem happy to do.

To avoid hammering you are going to want to ensure continuity of cutting ie try to get the second tooth to start cutting before the first tooth finishes its cut etc.

You'll never manage this with a flycutter or a single insert / single flute milling tool. Furthermore, unless you use a large fraction of the flute length on a fluted end mill, you won't achieve that on a multi flute cutter. It's always a good idea to use as much of the flute length as you can, otherwise you only wear out the tips. Reducing this hammering is another reason for doing so, although the advice is generally to avoid full width slotting and instead go for something like 20% stepover/ optimal load.


Thread: What did you do Today 2018
26/08/2018 13:43:13
Posted by Andrew Johnston on 22/08/2018 22:25:34:
Posted by David Taylor on 22/08/2018 03:14:12:

Andrew, do you need to use coolant on brass? I never do. You could stand there and blow the chips away with an air nozzle which I did for the steel parts. That was just to ensure the cutter was only cutting 'new' metal.

I found with the GWizard software the feeds and speeds it gave me basically melted my cutters on the 1.6mm steel parts. Perhaps it assumes coolant. I did specify HSS cutters. I dialed things way back to basically what I'd do on the manual machine and the steel parts went smoothly (if slowly).

Normally no; I machine brass dry. Coolant on the CNC mill is primarily to wash away the swarf, especially in this case where it's a pocket and the swarf won't naturally fall away. For me the whole point of CNC is that I can go away and do something else, so I'm not going to stand around for hours with an air blast! Although I have been known to use a vacuum cleaner when machining relatively quick parts in plastic.

I tried GWizard a long time ago and couldn't get any sense out of it. The answers always seemed pretty daft to me. I now just base speeds and feeds on experience and use a calculator or do them in my head.


David - from your album it looks as if you have a CNC mill, in which case you don't need to go near GWizard. I've never been impressed by it unless you like examples of self promotion above substance. Bob Whorefields has made a comfy life from it but you could spend your money on something more useful like actual tooling. There are better products available for free from the main suppliers (Sandik, Mitsubishi etc) including some handy smart phone apps.

The Excel feeds and speeds spreadsheet on the NYC CNC website is also generally useful for ballpark machining feeds and speeds. Worth a look and a play.

If you are using Fusion 360, you simply need to find the surface speed and feed per tooth for the cutters from the manufacturer's site (if using a recognisable product) or the more generic feeds and speeds from the likes of John Saunders' site. The CAM program within Fusion 360 will do all the rest for you, like setting the feeds etc. Have to admit that some of the latest cutters are capable of greater material removal rate than my machine can handle, so tend to do some tests and dial the loads back a bit but they are a good guide. As well as avoiding overloading the cutter, you also need to make sure you take enough of a cut to avoid rubbing etc.

I'd always use coolant for steel if I'm trying to shift some swarf. On the other side of the pond, Mercans seem to like those mist spray things. They provide very little cooling (primarily due to the air flow), so must be limiting the material removal rate and tool life. Better than dabbing oil on with a brush though, which seems little more than superstition.


Thread: Chester 626 Mill Column
26/08/2018 13:07:27

Here's an example.


Big steel housing for a battery tray that was too big / tall to fit "on" the table. Hung it out the back / over to one side so I could make some slots in it. In fact, hung it out both sides as that was the only way to access all of the surfaces.

Job done. That's a door mat to give some idea of scale.



Thread: turning tooling
23/08/2018 16:09:15

TBH, you'd need to be looking in a museum, as they haven't made featureless inserts like this for decades. Also, they aren't very hobby-friendly due to the negative top rake, which was all they could manage when inserts had a flat top and you needed front clearance.

Save your money and get a modern tool with proper chipbreaker geometry, modern composition and coating. Put that in a display cabinet instead.


Thread: 1.1 kW electric motor burns up..
23/08/2018 12:46:40
Posted by Neil Wyatt on 23/08/2018 11:14:20:

The blowing 10A fuses were a warning that something is imposing too great a load on the motor. It's likely that the root cause was either not running in at high speed or, more likely, excessive belt tension.

It is possible that the spindle friction is excessive, see how free it is without a belt fitted.

I think he had it right in his first post, last paragraph. Time to fit a proper motor, assuming it's past its warranty period. If it struggles to spin a 1mm drill (effectively zero spindle load), it's just not man enough for the job. Some of those Chinesium motors are just unadulterated crap.

Get a pukka European motor in there. Not sure where to buy one but a certain online auction site might be a place to look.

Worth checking the bearings aren't packed with the finest axle grease, as the load would increase significantly with speed. They should be only lightly greased (<20% of the space) and it probably wouldn't do any harm to clean them out and use oil instead.

Something should be getting hot if all that supposed shaft power is being absorbed in the bearings or belt. Suspect it's the motor though.


Thread: Belt Driven Hacksaws -
22/08/2018 20:11:56

Look about 2:48 into this video. I would suggest your motor and pulley are not parallel. Possibly one of them has become misaligned.


Thread: What did you do Today 2018
21/08/2018 22:28:16

I don't think it's generally understood why the paper tape / superglue trick works so well.

Check out a couple of examples:

Coolant and decent MMR

The long story

It gives a connection that's clearly very solid in operation yet allows the bond to be broken once the job is done. The tape tears once a fracture has been started - I think that's what marks it apart from solid superglue or shellac etc. Hopefully somebody with a strong armchair instinct could explain the mechanism.

Given the context of this thread, I should explain that I am (again) deprived of workshop access for the time being. Luckily I'm the devil's own cook, so concocted a load of cottage pie and generic mince for the freezer. It's not quite as fulfilling as generating swarf but will avoid me wasting away.


Thread: VFD damage?
20/08/2018 22:52:14

Log or linear??? It's a speed control where the voltage sets the speed, so hardly going to be log.

Although it's badged as an Omron, it's actually a Yaskawa.

Best take the cover / back off if you are bothered enough to want to fix it. You might then be able to bodge an replacement pot in place of the original. The value won't be critical as long as it's between something like 5k and 50k - consult the manual for the approved range of pendant pot values to be sure, as it's almost certainly using the same reference voltage.


Thread: Chucking a Small Octagon (Delicately and Accurately!)
16/08/2018 13:47:18
Posted by Mike Donnerstag 1 on 16/08/2018 10:43:32:

I'm setting up as a violin bow maker...

Can be quite lucrative if you are any good at it. I know one of my sisters paid "several" thousand tokens for a violin bow not so long ago. As an engineer (and in fact she is one herself), I'd have to wonder how such an investment could be rewarded with any tangible improvement in sound, given that the interaction is between a (consumable) bundle of horse hair and the string. So the bow is surely little more than a handle, albeit an elegant and comfortable(?) one.

I'm a complete musical philistine, as you can tell. However, any benefit would certainly have been lost on me - in my case the money would have been far better spent on machine tools!


Thread: Squealing motor
12/08/2018 12:53:35

You shouldn't be putting lots of grease into new bearings - the actual amount should be a small fraction of the free space. The grease isn't supposed to spend its life as if it's inside a mincing machine. NSK recommend 10-15% and they should know.

You'd have been well off going for sealed bearings rather than shielded. Then you wouldn't be reliant on the questionable (in fact buggered) original seal. And as the bearings would be already lubricated by the manufacturer, it would prevent fists of ham trying to "fill" them with grease. I think we can be fairly certain that an induction motor would be capable of overcoming any minimal seal drag at startup.


Edited By Muzzer on 12/08/2018 12:54:00

Thread: Eclipse magnetic chuck/baseplate
11/08/2018 18:33:38

I doubt if he would have paid anything like full new price if he "picked it up" and plans to use it for welding, given that they are about £800 new but perhaps I'm wrong.

Lots of handbag action here but as I said, they often get thrown out or sold off when they are ground down to near the limit or just past their best. I turned down the opportunity to acquire one for free 2 years ago (and the grinder it was attached to). Both were well and truly buggered. Might have been tempted to use it as a welding table but I have enough junk as it is. Should it go straight from the grinder into the skip?

You'll see that most non-armchair welders don't bother clamping their work and instead find that gravity is usually sufficient to make an adequate contact. No arcing or sparking and certainly nothing to threaten the chuck innards or surface. It either strikes an arc or it doesn't. Unless you connect the only earth connection to the actuation lever I fail to see how you could knacker anything internally if you tried.


11/08/2018 11:46:19

I doubt you would damage the magnets with heat or current as they are hidden inside the body of the chuck. If this has no further use as a magnetic chuck on a precision grinder, it may well be a useful welding accessory. Using a brand new magnetic chuck for this purpose would be like using a Roller to pull a plough but if it's yours you can do what you like with it, particularly if you didn't pay much for it and it has had its day. A lot of these seem to get thrown out once they have been skimmed down a few times.


Thread: Are you a Man or a Mouse When Milling?
11/08/2018 11:37:22

Well actually my point was that the geometry of these cutters (tooth profile and asymmetric flute positioning) results in lower cutting forces and less likelihood of judder / chatter, which would actually benefit light machines. Hence my reference to the way insert geometry, materials and coatings have come on bounds. These cutters are as tough as hell but also razor sharp(!!) and make my Chinesium cutters look agricultural in comparison. True, you might not make full use of their potential but will most likely a better result. As ever, if you don't look, you don't find...

Think how the geometry ("chipbreaker" ), coating and composition of inserts has come a long way since we had basic, flat topped lumps brazed or clamped on the end of simple holders. That process of evolution continues today with solid cutters - they haven't been left behind.

If you buy them on offer, they don't work out too expensive.


Edited By Muzzer on 11/08/2018 11:37:45

11/08/2018 00:33:20

Like indexable inserts, solid cutters have come a long way and some of the most recent ones are pretty darned impressive. I suspect many of the "hobby" ones mentioned are pretty traditional in geometry and material - and possibly fairly indifferent in terms of surface finish.

I recently tried out a new-ish cutter from YG-1 (Korean), the "V7" EMC85 series. There are various flavours available but mine was a necked long series that I used for both roughing and finishing steel. The removal rate was pretty special and the surface finish was pretty darned good. Many cutters leave a clear series of grooves where the cutting edge in not smooth but these boys were almost mirror flat.

No coloured chips here, as I was using flood coolant to clear the chips but as you can see, I was achieving a decent material removal rate. To get the most out of these you really need to use CNC, as you couldn't sensibly apply the correct feed rate consistently.

Here's the roughing operation.

And the finishing.

Thread: Lead acid battery charging
10/08/2018 21:34:53

Trying to "trickle charge" a PbA battery via a bulb will simply overcharge it and then proceed to convert the water to gas. Probably about the worst thing you could do. Apart from drying out the battery, it will generate a fine explosive gas mixture.

Why not just buy a proper 6V / 12V battery charger? It will cost you less than the replacement battery you will otherwise need to buy.

If you insist on trying to charge it with a DIY circuit, use a regulated constant voltage source of 7V (14V for a 12V battery). It's no great coincidence that this is the voltage generated by the alternator regulator and corresponds to the float voltage of a fully charged battery.


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