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Member postings for Steve Withnell

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

Thread: Warco Minor mill/drill
02/08/2020 11:50:41

Andy, this is how I added a DRO to the Minor. The DRO is simple type from Arceurotrade. Then I just took a piece of aluminium plate and bored a hole in it to be a slide fit over the spindle assembly. There is a caphead screw out of sight which acts as a locking screw to stop the plate swivelling.

The plate is then useful for hanging clocks off...but you lose the depth stop which I miss very rarely.


I drilled and tapped a hole for a mounting plate in the mill casting to hang the DRO off.

I have a graph somewhere of the the DRO readout plotted against the manual readout off the fine feed, apart from a stiction/backlash problem the graph wanders about all over the place!

mill.jpg

01/08/2020 18:11:40

Warco Minor? I cut these bevel gears on mine and machined the cams for the Nemett four stroke. So the machine does work. You must put a DRO on the Z or it will drive you nuts!

p1030390.jpg

Thread: Today's delivery
30/07/2020 14:48:26
Posted by MC Black on 30/07/2020 08:33:15:

I ordered a yard length of #10 - 32 studding from the only United Kingdom supplier that I could find.

It came wrapped in a layer of bubblewrap in a 3" diameter tube.

It was bent.

If it was in bubble wrap inside a 75mm tube and a metre long, it can't have been that bent! If Parcelforce managed to bend it without damaging the tube, then they must have had a touch of the Yuri Geller going on!

Steve

Thread: Opions sought on using the USB Photo Stick for photo storage
30/07/2020 09:46:41

I don't like manual backups of anything, because they get forgotten and the media lost. I have a load of USB sticks. Somewhere.

Cloud storage is often free depending on storage requirements and fully automated and 'always on'.

If you are like me and can't quite make the move to moving the electronic copy of my life onto some remote hard drive, then you can buy a NAS drive and have the 'cloud' copy tucked away in the house. I use 'Allways Sync' so that hard drive always contains upto date copies of work from any of my devices. The weakness in that plan, is that I make manual copies of the remote drive onto a portable hard disk once a quarter and then lock that away, off network.

Manual sticks I only ever use for file transfer - typically from the Laptop that generates gcode to the PC in the workshop that runs mach3, though I am tempted to put the workshop PC onto the network and get rid of those sticks altogether, because the temptation then is to alter the drawings on the stick, which then don't match the 'Final' versions on the laptop.

The irony is that I first got involved connecting cnc machines to ethernet to eliminate paper tapes in 1983/4 so I'm a bit behind at home!

Thread: Further Adventures with the Sieg KX3 & KX1
30/07/2020 08:48:26

I notice that the Axminster versions of the KX1 and KX3 have Ethernet interfaces, I guess that is yet another version of controller board. Anyone know which one?

Regards

Steve

Thread: Calculating Feedrates for drilling with the Sieg KX1
18/07/2020 19:09:40

Thanks Jason, I calculated manually 3032 rpm and 156 mm/minute which is a bit more aggressive, but I can see that I've been a bit optimistic with the "feed inches per revolution" value. If I back it off to where it should be I get your numbers. I'll go and run with that, see how it works out!

Regards

Steve

18/07/2020 16:38:43

 

I've been puzzling over the feed rates when drilling with a CNC. I found this table, but it doesn't link to material type. How do I calculate feed rates when drilling?

A specific would be drilling 3mm holes in EN3 square bar as opposed to drilling 3mm holes in aluminium. How do I go about calculating the feedrate in those different materials.  If I use that data, then I get to 150mm/minute in mild steel - is that about right?

Table:
 

Recommended Feeds of Various Diameter Drills

Diameter of Drill - Inches Feed Inches per Revolution

Under 1/8 001 to .003

1/8 to 1/4 .002 to .006

1/4 to 1/2 .004 to .010

1/2 to 1 inch .007 to .015

Edited By Steve Withnell on 18/07/2020 17:07:42

Thread: Which Milling machine and what is its footprint?
05/07/2020 18:30:09
Posted by Bazyle on 02/07/2020 00:18:50:

My Warco minor mill drill fits on a 2x2 bench. They don't stock them anymore just the bigger Major but the equivalents from several importers appear on ebay every week. Perfectly adequate for small work though people like to moan about round column mills. Tilting head is just another thing to go out of true. Tilting vice is dead cheap.

I still have my Warco minor and won't part with it. If you fit a DRO to the Z-axis and think through the machining process when setting up it's perfectly sound. It's also a very good co-ordinate drilling machine. One benefit is that it runs slow enough to cut gears (I've used mine to cut small bevel gears) and run slitting saws.

Good workhorse!

I agree, tilting the work during setup is a better option.

Thread: Gear Generator
26/06/2020 09:20:57
Posted by SillyOldDuffer on 25/06/2020 10:46:09:
Posted by Steve Withnell on 25/06/2020 10:17:48:

They don't make it obvious do they! Try this page, Personal Use 1 year. Next year they'll ask you renew it, still free for personal use. (How long it will stay free for personal use will last is unknown, but at the moment there is no intention to charge for it. I think the game is to establish lots of trained users who will lean on employers to get them the commercial version. Might work - it's far more expensive to train people than buy software.)

Thanks Dave.

I've been using Eagle and that's full on too, but just about got that sorted. I'm struggling at the minute to move from 2D (Vectric Cut2D which is dead simple) to 3D packages.

Steve

Thread: Mamod safety valve
26/06/2020 09:13:53

Hi Martin, what thread sizes did Mamod use for the boiler fittings? (Whistle, valve, drain). Dad has a couple or three engines with the various bits missing.

Steve

Thread: Gear Generator
25/06/2020 10:17:48

F360 is pretty expensive - Although I have an Autodesk Eagle licence, which it claims entitles me to F360 free as well, it wants confirmation I'm a student at an approved college? I'm clearly going down the wrong path of internet links...

How long does it take (devoted hours) to get reasonably proficient at producing simple 3D models in F360? I want to be able to (as an example) machine camshafts on my KX1 using a rotary table as the fourth axis and engrave labels round the circumference of a round bar.

Regards

Steve

Thread: 2mm endmill help
25/06/2020 09:24:26

When I started out wth the KX1, I downloaded an 'app' onto my phone called speeds and feeds. If I bang in Andrew's numbers for an uncoated 3 flute HSS cutter, 0.4 DOC, then it gives a feedrate of 130mm/min roughing and 65mm/min finishing.

In practice what I do for a first time cutter/material is to load the finishing number, then wind up the feedrate overide keeping an eye on finish. I find that I don't break cutters (I've been using 0.5mm - 3mm in the last round of jobs) with this approach. Once I've 'learned' a good number, I then bake that number into future jobs for that cutter/material combination.

One good trick for breaking a lot of small cutters is to inadvertantly set the tool offset wrong on a cutter change and then keep changing the feedrate to solve the problem. Oops.

Steve

Thread: Gear Generator
24/06/2020 19:56:49

Thanks for the tip on Freecad, just downloading now.

Steve

24/06/2020 15:05:35

Sort of model engineering. I came across this site:

**LINK**

For a $2 Paypal payment you get 24 hours to download as many gears in .dxf format as you need.

Once you have the .dxf files you can then scale them up as you wish. I upscaled these in CUT2D and then had the KX1 cut them out. This is a set for a toy for my Grandson -

busy gears.jpg

Thread: Vogvivo CNC router - Is anyone using one of these?
07/12/2019 15:33:57

I've been using the KX1 to produce some basic PCB's, which is overkill really and the spindle speed is a bit limiting.

Mach 3 will drive this and the spindle speed is 10k so should be better suited to cutting PCB's and I can use it on the kitchen table rather than retire to the workshop!

**LINK**

Some of this stuff can turn out to be junk - so anyone run one of these?

Regards

Steve

Thread: Why mostly manual cars in UK
07/12/2019 15:29:30
Posted by jimmy b on 07/12/2019 10:20:32:

I've been driving automatics for 30 years.

Modern auto boxes are quite amazing.

Why anyone would want to have to mess around with gears is a mystery to me......

Jim

I've been driving manuals for 40 years. I now have an 8 speed automatic and it's magic, will never go back to manual. Absolutely suited to our massively congested road systems.

Thread: Feeds and Speeds! 0.4mm milling cutters...
05/06/2019 17:58:44
Posted by Joseph Noci 1 on 31/05/2019 20:19:00:
Posted by Steve Withnell on 31/05/2019 18:08:53:

Looks fantastic Joseph!

One other poster had a strong recommend for 60 deg cutters - sounds like you are at the other end of the range with 10 deg cutters?

The PCB I'm looking to cut is pretty exotic stuff - RT6035HTC. As you say, the cladding is 35um.

What I've just discovered is the substrate is ceramic loaded with PTFE! Ceramic doesn't sound good at all, but worth a try. Otherwise its going to have to be back to chemi-etch which I really want to avoid.

The board is for a 300Watt 2.4GHz amplifier (think solid state microwave) so needs excellent heat tolerance hence the ceramic.

Steve

Hi Steve. I am not really advocating specific included cutter angles at all - My approach is to use the largest angle possible, in keeping with the complexity of the board to be engraved. If your flavour is 0.1" pin spacing with one track between pins, then a 45deg cutter will do fine. The advantage of wider angle cutters is the robustness of the tip improves, and wear is less. Control over width of engraving does suffer though. A 45deg cutter will cut a much wider groove for smaller depth increase than will a 10 degree cutter. So a lot depends on how well you can control cutting depth, how rigid the machine is, etc. A floating head controls depth just fine, assuming a good vacuum system for chip removal so that the float rides on clean BURR FREE (!) PCB.

RT6035HTC is a Rogers laminate. It is still quite flexible, ie, it is not like a ceramic kitchen tile....The ceramic is added not really to increase heat resistance but to increase the dielectric constant, so that strip-line lengths are reduced, ie, wavelength of RF propagation reduces, so stripline dimension reduce ( Wavelength = Wavelength in free space / Sq Root of the dielectric constant). PTFE already has a constant around 4 ( effectively halving the propagation wavelength)or so, and the ceramic can take this up to 7 or 8 quite easily.

Engraving this material is in fact a lot easier than normal FR4...The laminate is not glass hard as the ceramic powder is embedded in PTFE, so the cutter penetrates and cuts quite easily - easier than in fibreglass. The problem with RF circuits on this type of laminate is that you normally remove large areas of copper, ie, it is not just track isolation as in normal digital or analogue circuitry. Striplines that form the inductors and capacitors in uWave RF PCB circuitry have very critical dimension tolerances and proximity to other conducting surfaces, worsening with increase in frequency..

And removing large copper areas on a laminate with even a 90deg cutter is tedious as best...You would need to use carbide flat end mills for that, and depth control is critical if you wish to maintain your stripline size computations...

One of my Career Lives was in uWave RF design - up to 76GHz, so experience has burnt many of my fingers...

regards

Joe.

PS - I presume this is for a radio Amateur application? 300 watts in the 2.4GHz ISM band may otherwise land you in none-to-tepid water...

Interesting! Yes it is for an Amateur Radio application - Oscar 100 satellite. Not me by the way, just enjoy building the stuff. I managed to finish a 2.4Ghz filter to sit in front of the PA which looks like it is proving close on 50dB suppression of the mixer signal whilst the insertion loss is c0.5dB at the centre frequency.

I've been playing with FR4 and with a brand new 5mm carbide cutter, the large areas skim off really nicely. I've experimented with 2mm, 1mm and 0.5mm milling cutters and getting good results. The is no requirement for 0.1inch matrix for this board. My 'customer' has simplified the PCB design, so I might get away with 1mm cutter for the edge of the tracks and a 5mm cutter to remove the waste areas.

Given 5G is targeting 76GHz then there will be plenty of work to keep you busy! Lancaster Uni have developed some backhaul radio systems at 94GHz. for 5G, so lots of interesting stuff going on.

Regards

Steve

31/05/2019 18:08:53

Looks fantastic Joseph!

One other poster had a strong recommend for 60 deg cutters - sounds like you are at the other end of the range with 10 deg cutters?

The PCB I'm looking to cut is pretty exotic stuff - RT6035HTC. As you say, the cladding is 35um.

What I've just discovered is the substrate is ceramic loaded with PTFE! Ceramic doesn't sound good at all, but worth a try. Otherwise its going to have to be back to chemi-etch which I really want to avoid.

The board is for a 300Watt 2.4GHz amplifier (think solid state microwave) so needs excellent heat tolerance hence the ceramic.

Steve

Thread: ST Governor
31/05/2019 17:58:29
Posted by Philip Burley on 31/05/2019 16:08:06:

I have been making up a ST governor for a ST beam engine . The spring like belt supplied is far too long , Has anyone else found this ? or what else can be used as a belt ?

regards Phil

I have one of those belts, but never used it. I've assumed it joins just like a Meccano belt where one end is a tight spiral that you 'screw' into the open end. It must be joined in some way?

Steve

Thread: Feeds and Speeds! 0.4mm milling cutters...
30/05/2019 21:18:21

Well I got that one wrong - turns out they are not cutters but drills! So I do need to look at getting some engraving cutters...

I'll also take a look at ramping, I've seen the function in the CUT2D screens but not tried it out yet.

Next stop Woody's Workshop!

Regards

Steve

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