Member postings for Adrian R2

Curious, so what in the model eng. world costs £20 per cm and do I have any in my oddments bin?

You can balance the vice by clamping an offcut in the other side, may help a little, or if you have the facilities perhaps make a set of long, shallow "v blocks" to go in the vice and give you the required stick out.

Or buy longer stock so less ends per useful cut, using another vice or clamp to support the free end of the bar so it doesn't push out upwards.

Edit - thinking a bit more, you want something similar to a woodworkers mitre box, maybe a bit of aluminium channel and some additional clamps?

Edited By Adrian R2 on 23/01/2022 11:52:33

Indeed - the rectifier is a black blob and I haven't examined it further - from measurements110VAC goes in and 110VDC comes out, but I don't have an oscilloscope so I don't know how clean it is. With two working coils you can use the thing upside down for drilling overhead beams (with safety strap for power outages) but I don't intend to attempt that.

I will investigate further at the weekend and report back if anything interesting results.

Ok, so my measured resistance is supiciously high. No docs available, so options are:
1) Try a different DVM
2) Measure the current in operation for the good coil and see if that agrees
3) Dig out the coil and examine it
4) Just go with 31 gauge & cross fingers

Edited By Adrian R2 on 12/01/2022 16:41:25

Thanks - Clarification: the measured resistance is from the working coil, the non-working one is open circuit.

There isn't much circuitry inside, just a black box rectifier than turns input AC into DC and splits it to two connectors wired in parallel.

p.s. to your p.s. Yes, that video is what I had planned but I started with the desk calculations rather than pulling anything to bits. Interesting that his coil resistance is 1/3 of mine. I don't have the CNC lathe coil winder either!

Edited By Adrian R2 on 12/01/2022 15:44:16

I picked up a spares/repairs mag drill from you can guess where. It has two coils in the base (wired in parallel), only one works which is OK but not great so I'm contemplating whether it is worth trying to fix the other. Replacement part costs almost half the price of a brand new drill (+VAT+shipping) but that's the usual spares pricing right-to-repair rathole so we won't go there.

So, I am assuming it is a simple round coil in resin which could be dug out followed by winding a new coil on a former to be slid in, connected and then resin refilled. However my attempts to calculate required wire size don't add up - it's 110V and I get ~420 ohms resistance with my DVM, but playing with numbers from Wikipedia table of enamelled wire sizes suggests that the length I would need to match this won't handle the current or fit in the allocated space.

Where have I gone wrong? How should this be done?

p.s. additional info, coil is 50mm ID, 75mm OD, 25-30mm deep so cross section of ~ 25*12.5mm^2

Not answering the question:
- add some telescopic gas dampers to moderate the descent rate independently of the jack, or
- replace jack with screw operated type and use a cordless drill to raise/lower
- add prominent warning label "release cautiously, platform may drop faster than you expect" or similar

Cordless compressor? Didn't that used to be called a foot pump? Anyway, let us know. I would guess it's only really designed for topping up tyres or emergency use for one flat so you would have to be careful with duty cycles, but the 2Ah of battery capacity might help regulate that.

Hmm - assembling something like that with only a keyway seems a bit odd to me - usually if there is _only_ a key then it is a tapered one and if so how would you get it in/out? I would think there must be either a grub screw or some clamping arrangement on the pulley section.

Can you post a picture with that back gear cover removed? Not that I have any direct experience but it's a bit like a Christmas quiz for tinkerers.

If no-one else knows for sure then I will hazard a guess that the spindle comes out towards the tailstock (right), as that would be against most of the cutting forces. I would also check to see if one of the castings supporting the spindle bearings looked to be the larger than the other, and assume that it would be the larger end through which the shaft would pass to assemble/disassemble.

Some of the designs on lathes.co.uk show clamp nuts, others just a cover but not what lies underneath.

Just out of curiosity, and without predudicing customer/supplier confidentiality, what is the order of magnitude for this type of work? Are we talking tens, hundreds or thousands to get something made?

Background: Not model engineering - I designed a towbar bracket for my bike in Fusion 360 and had it 3D printed for £15. It might be strong enough, but if not then can I give the same file to a foundry and have them make me one in aluminium without it costing more than the bike itself?

On Youtube you can find a video from "Trev's blog" where he shows how to carefully weigh out and mix small quantities of 2 pack paint - OK that is automotive small, not model engineering small, but may still be helpful.

Sadly a worse insult is likely still to come. The DVLA are still in a total mess and your paper application will probably moulder in a warehouse in Swansea for many months before someone gets round to opening it.

https://www.gov.uk/guidance/dvla-coronavirus-covid-19-update#processing-dates-for-paper-applications

Alternatively, if they all had EVs with V2H (Vehicle to Home) then they wouldn't have been without power. This is part of the sales pitch to in the US for the F150 lightning.

I don't know the machine, but you say " I did remove the chuck guard and microswitch...but bridged that connection with a link.."

Might be worth testing the microswitch you removed to see if it was NO or NC - perhaps your link is telling the machine the guard is open and thus inhibiting the start?

I would definitely suspect the safety switches - I have a mini-bandsaw bought as "not working spares/repair" which turned out to be nothing more than a misadjusted door switch.

<edited for typos>

Edited By Adrian R2 on 29/11/2021 16:10:04

The paint that I buy from the local agri. supplier seems to go on better and last longer than anything from the DIY store so if you have one handy then go and see what they sell.

Many paints aren't what they were for environmental reasons - red oxide was originally red lead oxide, so I doubt the current stuff has much in common with the original apart from the colour.

For the record, UK gridwatch shows power generation from coal is back down to zero today. Nice timing for the COP26 announcement eh?

Edited By Adrian R2 on 04/11/2021 12:01:35

I use one of the generic citrus degreasers for general cleanup duties - they seem to do the job, plus they smell nicer than some of the alternatives and are safe for disposal. Comes concentrated in 5L containers so I dilute into a spray bottle, squirt on, leave/scrub/rinse/repeat. Using warm water helps too.

[edit] and I try to do it on a warm sunny day so that ferrous parts can dry, if not then have cloths or heat gun ready, or paint straightway to avoid flash rust.

and yes, very nice model, well worth the effort.

Edited By Adrian R2 on 01/11/2021 14:20:00

I don't recognise it but dimensions may help, particularly width of bed and height to centre.

Not answering the question, but have you considered using a plastic coated bicycle cable locks?