Member postings for Muzzer

Reminds me of these apple peelers:

**LINK**

This one looks as if it could almost turn a thread with a few minor mods. Presumably this could be marketed as "semi-automatic"?!!

Merry

CAD model for Bantam-specific blade holder coming along. Basic section defined and extruded. Model of blade ready for assembly. WIP.....

Planning to use an end mill for the 15 degree lower lip.

I've ordered one and probably won't see it for a week or two. In the meantime I'm making up a toolholder for it to suit my Bantam QCTP.

I'm wondering what the height of the blade is. And before you say 32mm, I'm pretty certain it's less than that. The 32mm seems to refer to the maximum height dimension of the rhombic space the blade fits into. However, as both sides of the long faces of the blade (the 150mm long ones) are chamfered at 15 degrees, the resulting height of the blade will be closer to 31mm I suspect.

They say it is compatible with industry std 32mm blade holders so perhaps a different make may also have the same dims.

This snip from the Korloy brochure illustrates my point. "H3" is 32mm, so what is the height of the blade? When I model it in CAD it comes out just over 31mm.

Any real world measurements would be very helpful so I get it right in the absence of the real blade. Thanks.

Muzz

If you don't tell the inverter that it's actually got a smaller motor connected and it tries to generate full torque or boost torque, it's going to put some serious amps into the machine that it wasn't designed for. This is likely to saturate the machine and certainly won't result in the required performance. And the various operating and protection schemes for the motor and inverter won't be set up correctly.

Modern inverters do some wonderful things as noted but they need to know some key information about the motor. This often requires little more than entering the motor plate ratings but it's worth taking the time to do so and isn't usually difficult.

So you don't have to choose matching motor and inverter but you should "match" them by correctly setting the inverter up. Obviously there's no harm running a large motor with a small inverter (the max limits are hard coded) but you simply won't be able to develop the rated torque and power due to the current limitation.

Merry

I had a couple of issues with it crashing. The recommendation seems to be to save often which sounds like good advice. It seems to be very much WIP in some areas but will hopefully "harden" (software term) with time. If it does so, it promises to have a lot of the functionality of the "proper" parametric applications.

Wouldn't be surprised if it struggled with XP unless you have chosen to marry a powerful machine with an old OS.

They all claim to be intuitive and in some ways they are - but all in different ways! Perhaps I'm just getting too old...

Don't know which ones you've been given as I can't read your PMs. However, from an early US manual here is one schematic for power feed. Sounds as if it's probably different to yours but it's quite interesting. The old 741 opamp is in there along with lots of old transistors. Quite a lost art designing that kind of stuff...

Merry

Here's the flow characteristics for the Grundfos 15-50 pump in my system. BTW, it suggests you ensure at least 7.5% of the max flow as a minimum but as I said it's hardly critical. It can develop the best part of 5-6m head of water (suds) which was what I was checking when I found this.

I have a Grundfos CH pump on my Bridgeport clone although it's the 3 speed version. I run mine on the high setting to get it primed quicker. As noted, you need to mount the inlet below the fluid level. Being paranoid, I have a plastic box under it (a shopping basket) in case it leaks, which of course it now hasn't.

These pumps are fine with a static head ie no flow. The only downside would be that it (and the fluid) would get warm after extended periods but why would you run the pump with zero flow anyway? And it wouldn't get very hot even then.

I simply vary the flow with the nozzle. If you want to get really clever you can download the flow characteristics for these pumps which show that they can develop a decent head but nothing too silly. Trying to vary the speed would seem rather pointless given the ease with which you can achieve the same outcome(!) with a simple tap. I'd post some pictures of my setup but there is very little to see.....

Merry

Interesting - some years back when I worked at Motorola, I did some research and life testing on filament bulbs. I forget the precise details but the life of the bulb fell inversely with something like the 5th or 6th power of the filament temperature. Obviously this didn't fall significantly in your case or the brightness would have been visibly different but with that sensitivity to temperature it makes sense that even a small reduction in the temperature could have a significant beneficial effect on life.

Eventually the filament evaporates(?) enough that you will see a failure but I know what you mean - the cost of bulb replacement probably outweighs the cost of electricity (and fuel and postage...)

Merry

Presumably you could put a gudgeon pin in and then use an eye bolt to hold the thing against a faceplate or into a short mandrel. Might be more secure than adhesive, less bu99ering about and less chance of splitting the blessed thing on a cone?

Muzzer

John

Yes, I completely agree with you about being left in the lurch when the academic license is pulled at some future point and I am most unlikely to be able to justify the commercial license. In my case, I was mainly attempting to pick up Solid Edge so that I could help(?) my daughter who is required to use it as part of her engineering course at uni. I have to say, I suspect she has left me behind already - quite a sobering outcome! I have mixed feelings about devoting time to learning a tool I would have to leave behind at some point.

The Freecad development is a pretty interesting application I've not seen before. It seems to offer all the benefits of parametric modelling and is clearly aimed at becoming a fully featured design tool. Thanks for pointing that out - as you suggest, this is a good fit for the likes of us who fall somewhere between the professional and the hobby user.

I'm not an expert on the history of 3D CAD development but it seems that Autocad, Alibre and others (possibly including Solidworks) all use the same "ACIS" kernel for their 3D applications, so I wonder how this open source project has managed to create its own equivalent without falling foul of the patent coverage, now owned by Dassault.

I'll definitely be taking a closer look at this myself and I'd be interested to know how you get on with it too.

Muzzer

There's another "proper" 3D parametric modelling option that's free for non professional use called "Solid Edge" by Siemens. My daughter who's studying engineering asked me to have a look at a 3D modelling exercise she was stuck with. I downloaded the student version and was able to open her model and help her to bottom out the issue.

Although it's a student version, it's got pretty much everything you'd need if you were wanting to learn how to use 3D CAD. Compared to even the full version of Alibre / Geomagic / Cubify it seems pretty powerful. It's obviously similar in capability to Solidworks, ProE etc.

It says that it's for "students at high schools, colleges or universities or for those studying outside work", so as long as you aren't planning on using it for professional applications, you seem to be free to download and install it. It has the full set of import/export, sheet metal, assembly/part drawings etc. There are also tutorials, videos and various books to support you in learning how to use it. At some point obviously you'd need to go out and buy a CAD package but unlike some of the apps, with this you have a year or more to check it out before you are forced to decide if you want to cough up. 30 days is hardly enough time to make that judgement if this is a part time activity trying to fit in with everything else in your life.

**LINK**

Here's a video:

**LINK**

Muzzer

There are several reasons why it doesn't work, starting with the tiny space for swarf to form and no means of clearing it. It's rather like using a hacksaw blade for parting off. Or holding a file or sandpaper stationary on a rotating workpiece. Once you've tried it, you realise it doesn't work and move on....

I only subscribe to MEW because I'm not the model building sort. I like reading about other people's exploits and seeing the results. Ever since MEW came to be, it's the one I'm happy to subscribe to. By and large I'm happy with the content.

I have to say I doubt many people would actually build such a beast, so you could probably miss out on all the detailed drawings and concentrate on the narrative and pictures. I think I'd rapidly tire of endless detailed drawings of a home made grinder which would seem rather pointless given the limited or possibly non-existent number of people who would do anything with them. Spending months drawing all those parts up seems a significant exercise in its own right.

Although I would admit to being more of a tool maker than a model maker, if I wanted a grinder I'd generally go and buy a used industrial example and then spend my time fettling and augmenting it. It's not as if they are ruinously expensive, whereas the materials to build a complete machine from scratch would be - you aren't going to be making one of these out of your scrap bin.

Like Andrew, I'd much prefer to learn about how to use a proper machine than watch someone attempt to reinvent the wheel.

Muzz

The red connector you have is a modern IEC connector for 3-phase plus neutral and earth, not surprisingly. You'd be surprised to find anything else these days. You don't have a neutral in your case so it can be left open. If you were making up an extension cable then strictly speaking you should connect all terminals through.

As you can see, there is a whole messy legacy of colour schemes but nowadays they are harmonising towards the IEC60309 std globally.

Your original connector and cable are some bizarre legacy scheme by the looks of them but assuming it worked before, the earth is clearly identifiable and the 3 phases must be the other 3 wires. So you just need to make sure you don't connect one of these to the neutral connection of your converter. And if you connect it up and the grinder goes in reverse, you can swap any 2 of the 3 phase wires.

Given that the converter seems to have an IEC socket, you should wire your mating IEC plug using the IEC convention - and identifying the empty neutral connection carefully in the process. I expect you'll find that the terminals are identified by lettering in the moulding. If not, look it up:

**LINK**

The 2 wiring diagrams show how you can connect the grinder motor in either star or delta according to the supply voltage, assuming you have a 6-wire motor. As noted, a neutral connection is not required for either.

Merry

Edited By Muzzer on 19/10/2013 23:04:34

Doesn't sound as if it's critical either way but the UNC has 60 degrees and Whit is 55 degrees so arguably a thread gauge and a magnifying glass might give you the answer. Pity it doesn't have a 1/2" thread as that would give the game away definitively. My milling machine (Taiwanese BP clone) has Whit, UNC and Metric all together, all original. You got away lightly!

Merry

Stub, presumably like me you played with nitrate to make bangs, not nitrite? Although they are both oxidants, nitrite is highly hygroscopic, even more than nitrate, so any "mixtures" you made would soon become very wet.

The biggest bang I ever made was actually a lot simpler than the classic chemical mixtures, even the ammonium nitrate/aluminium (poor man's Ammonol?). I took a 50 gallon oil drum, added a pint of water and screwed the cap back on, then lit a bonfire under it. When the ends started to bulge like balloons, I reckoned it might be sensible to retreat to a safer distance. This turned out to be a good instinct. I never found the end of the drum that flew off. And the drum itself ended up about 50m away. Funny thing was, I was living in Northern Ireland at the time, during The Troubles. I made myself scarce before Plod arrived!

Could have cut someone in half. A vivid illustration of the energy that can be stored in compressors, boilers and other pressure vessels and the importance of ensuring they are correctly rated and tested.

Merry

I'm pleased to report that I've now machined my 3 radial bores and they came out at exactly 19mm rather than the 19.1 I'd expected. I ended up making 3 passes with the final setting. Presumably the bar still springs enough to be noticeable but then it's only a 12mm one and there's a fair bit of overhang. Feed was 3 thou/rev and speed about 400-600 depending on the heaviness of the cut.

Bottom line - I tried one of the cams from my Bantam spindle nose and it fitted rather nicely (this part is the main body of a D1-3 spindle nose that bolts to a machine table). Given the way the different bores break through into each other, the result was pretty good, with no obvious changes of finish or signs of chatter. It was a bit of a pig to debur but I seem to have managed it now.

The thing looks remarkably like the CAD model except for a 1 degree discrepancy between the actual and planned positions of the cam bores due to poor setup obviously. It means that as it stands I can't insert the chuck pins with the cams in place. Luckily the angular error was in the "right" direction, so I can elongate the holes for the chuck pins to compensate and it will function as intended.

After an hour or so of measurement and setup, I'm ready to have a go at this tomorrow. Reboring the 15mm hole about 0.6mm from where it is should be another test of the bar and my own skills. Things could go horribly wrong! Then the final challenge will be to make up 3 eccentric cams to complete the spindle nose.

I'd post a photo but the "edit photos" link isn't being very helpful unless you are looking for "page not found".

Muzzer

Pretty much:

= 2*($C$2-$C$3*SIN(RADIANS($B6))), where

...and B6 is angle (degrees!)

Yes, the problem is fine adjustment. Without complicating it too much, I can only think of a vernier scale by way of practical adjustment, but that's not going to happen.

What I did in the end was to plot the variation of the final diameter against the angle of the bar relative to the carrier. By entering the actual max and min measured, I can scale the curve to what I actually have rather than I might theoretically have ended up with, as I can infer both the eccentricity and the offset fairly closely. Then, after boring and measuring an undersize trial hole, I was able to estimate the angular correction required. Setting that angle was the tricky bit obviously, but it's easier to implement a small correction than to get a large angle spot on.

Obviously it took me a couple of goes to get there but in the process I was able to have a go at boring some real holes of increasing diameter in a piece of 2" steel square section. I seen worse but it's clear that a deeper cut (top) gives a cleaner finish, so I won't try to creep up on it too slowly. Given that I'm looking to bore a 19mm hole, I'll leave it where it is. Fortunately, I have 2 boring bars and 2 eccentric holders now, so I can use the other one to perform the one or two roughing cuts and then swap them over for the finish. Well, that's the plan at any rate.

Muzzer