Member postings for Steve Withnell

Just install "CamelCamelCamel" add-on into your browser - when you browse an AMazon item, it will give you a price plot over the previous months.

Sometimes on high value jobs, to measure twice, have a brew and read the paper, then measure again before cutting! Measure twice sometimes means you measure wrong twice...

The F35 (JSF) stealth capability is  reliant on BAE Systems manufacturing technologies - so they are not wholly American planes. The original consortium was Northrop, MacDac and BAesystems.

Steve

Edited By Steve Withnell on 17/08/2017 22:46:34

When the TSR2 was cancelled, a fair few designers breathed a sigh of relief! TSR2 was not our finest hour.

Steve

Then of course there was that privately owned Spitfire that crashed at an airshow some years back. CAA determined it had been flying on one magneto for six months or so.

H&S? I went to my Dads last weekend to demolish an old shed, so I put on my hardhat - Dad said "there is no H&S nonsense here" so I through it back into the car. Banged my head twice - "That's because you are used to wearing a hard hat instead of looking what you are doing!". Anyway, won a nice little bandsaw out of the escapade

Steve

(But I didn't find anymore SuperAdept's Neil! - but a stash of old gear boxes - if you are a Singer 9/10/Roadster rennovator 30's/40's, drop me a PM)

Not yet, but soon...

The saw doesn't have loads of power to spare, so perhaps 14TPI is the best compromise.

Steve

It sounds like it's OK, but what is actually best? The blade that is currently fitted is 14 TPI and coming down to 10 or 6 TPI might help prevent the blade clogging?

Steve

Thanks for that. Given that I want to cut 20mm and 30mm plate (I tried 30mm earlier and its happy with that too) then should I be thinking about 6 TPI blades? Never thought about thickness driving the TPI requirement, so every day a school day!

Steve

I've finally acquired a little Record 3 wheel bandsaw, 'found' under a tarp at the bottom of the garden at Dad's place. Been there a few years. Just powered it up and it will eat 10mm ally plate without trouble. The blade spec is 56.5 inch blades 1/4 or 3/8 wide.

Since I want to make straight cuts, I'm assuming 3/8 wide is best, but what about TPI? The commonly available blades are 14TPI for metal cutting, but I've found a supplier that can do 24TPI (which is what I use in my handsaw for Ally).

Anything else I need to watch out for when using this Bandsaw type? It's a Record BK3, but it does look like a cheap import.

Steve

Edited By Steve Withnell on 13/08/2017 11:26:17

So, I had just enough clearance to drill and tap 4mm, loctited in a brass screw, skimmed flush, tapped out 2.5mm. Perfect!

What is it?  23cm Bandpass filter to stop those cell towers wiping out 23cm receive front ends!

Edited By Steve Withnell on 19/05/2017 15:09:34

Thanks guys, out of the armchair and into the shed...

Steve

As per title. Being a bit clumsy, I've managed to pull the threads on a couple of holes I was tapping in aluminium block - blind holes. How can I repair the damage so I can tap the holes correctly?

Thanks

It's all bollocks really.

Steve

Would I buy one of these...

**LINK**

Steve

I've been thinking about buying one of those KX1's for a while now and have a couple of projects where I thought they would be great.

One of them involves drilling a lot of accurately placed 2mm holes, 10mm deep into 6062 aluminium. When I started doing this manually, the aluminium kept sticking to the drill bit, so every hole had to start by cleaning the flutes of the drill and unsticking bits of aluminium, then brushing with a bit of parafin as a cutting fluid. Drilling manually, it's possible to feel the drill getting clogged up.

Struck me, that with a little CNC, this would be a problem and rule out using a CNC. I must be doing something wrong somewhere as that manual process isn't happening on production shops!

The spindle was running at 2000rpm or thereabouts.

Steve

Edited By Steve Withnell on 10/04/2017 21:59:26

Very nicely done!

Steve

Here is the design programme I'm using. Changing the rod diameter does not change the Q, so I'm assuming (!!) that the rod diameter does not make a material change to the overall filter performance, so the maths isn't included in the code.

**LINK**

So far I've made a 3 pole version for 1090MHz and a 4 pole version for 1249MHz, both close to the design spec. Sounds like polishing the copper rods and applying some lacquer solves all sorts of issues!

Steve

PS: I also have the BASIC code for this calculator,  but there is a bug I can't find.  Any wants a copy let me know!

Edited By Steve Withnell on 27/03/2017 21:10:12

This is one I made earlier, without the silver plating...

This one has a centre frequency of 1090MHz to stick on the front of one of those SDR TV sticks, to capture aircraft ADS-B signals. (Which when the moon is in the right phase, gets uploaded to Flightradar24 and gets me a free subscription!)

Silver plating the rods should improve the filter performance, the interest is in measuring by how much.

From a hobby machine shop point of view,  I took Jason's advice and mounted the aluminium blank on the face plate of the lathe and bored out as much of the waste material as possible.  The advantage is that the chips just fall out naturally,  whereas on the mill,  you end up with the task of continually clearing out the chips.

Steve

Edited By Steve Withnell on 25/03/2017 19:47:46

I'm looking to silver plate some copper rods as part of an RF (1.3GHz) electronics project, and while I can find formulations for electro-cleaning the rods prior to plating, I can only find one source of silver plating solution which is £35 for 250mL, but I can't find any info on its formulation - cyanide free that is.

I want to coat three rods in about 2-3 microns of pure silver as a test to see if there is any material improvement in performance over the raw copper, if there is then I'd be looking to silver plate upto 30 rods.

The coating does not need to be a bright finish, which seems to be the difficult bit, but just a nice uniform coat of pure silver.

Anyone got a formulation I could use make up to do some trial plating?

TIA

Steve