Here is a list of all the postings mgnbuk has made in our forums. Click on a thread name to jump to the thread.
|Thread: What did you do Today 2018|
New toy arrived at work yesterday, connected up on the dining table (as you do ....) today to make sure it works - which it appears to do. Bought from Ebay seller pjsparker, it was ordered on the 8th of this month, notified as despatched on the 12th & delivered (in two packages delivered by two different carriers) on the 17th.
This is destined for my Taiwanese FB2 clone. I was thinking of changing this machine for one of the WM18 type, but recent events (plus a lack of ready availability of a 3MT machine) prompted another measure-up of the FB2 - it is a bit shorter in the table travels than the WM18, but has a good spindle-table clearance & I know it is reasonably accurate all round. So I decided to improve its usability with the DRO & have a stepper motor feed on the go for the head.
|Thread: Proxxon lathe PD 400|
I have NOW used a test bar and it is pointed nicely at a centre held in the tailstock ... the error only shows up when cutting ...hmm ... hmm ... that might point the finger at the roller bearings...
But have you checked that the bearings are correctly adjusted before condeming them ?
Mount a chuck & chuck up a length of stout bar. Set a dial gauge from the bed to indicate at the top of the chuck backplate (12 o'clock). Grasp the bar & lift it away from the bed firmly. If there is lift in the spindle, it will show on the dial gauge. Adjust the bearings until you get no lift, add a small amount of preload & try a turning and boring test again - do both to see if the taper problem is apparent inside & out. If you cannot adjust to a "no lift" situation, then consider replacing the bearings.
When rebuilding CNC lathes in my last employment (much larger machines than a Proxxon !), we used to "bump" front bearings off the spindle. The spindle was stood upright on its rear end on a piece of wood (railway sleeper), then a stout bar was bolted across the chuck mounting face. Two of us lifted the spindle a few inches off the sleeper (the top of the spindle was about shoulder height with knees slightly bent from the floor/ sleeper) then dropped it vertically. With repeated "bumping", the front race walked off it's seat with no damage caused. The spindle also had a safety sling loosely mounted from the O/H crane so it couldn't fall over accidently if we got "out of sync" with the lift & drop sequence. The replacement bearing was warmed with an induction bearing heater & then it just dropped on.
Joe's experiences re: loose bearings appear to be different to mine - spindle bearing problems pretty much always manifested themselves as surface finish defects for me, not alignment issues. 0.002" lift on a newly rebuilt machine for an oil industry customer was enough to fail acceptance due to chatter while screwcutting - adjusting the bearings so there was no lift (which required the use of a crane on a bar bolted to the spinlde nose - couldn't tighten the adjusting nuts sufficiently by hand !) completely cured the problem. These were "NNU" type expanding roller bearings , though, not taper rollers - but a loose spindle is still a loose spindle regardless of the bearing arrangement ! At the employer before that, heavy lathe spindles were preloaded by running temperature - if the headstock didn't get to 40 C after a predetermined period at full speed, they were too loose, over 50C they were too tight. These were taper rollers, a "fixed" pair at the front end & a "floating" pair at the rear - as the hollow spindle passed 16 5/8" though, I would guess the bearings were around 24" bore.
lathe boring taper, not parallel.
How is it turning ? Are O/Ds not parallel by a similar amount in the same direction ?
I would expect a bearing issue to show up as surface finish / vibration rather than taper on the workpiece. Clean, smooth, shiny taper roller bearings sound like new ones ! I would regrease & re-install them, then set to zero play / lift (or slightly preload) and try your cutting test again, both boring and turning, before diving in further.
Have you tried checking the headstock alignment ? The usual way is with a Morse taper test bar in the spindle socket, with a dial gauge mounted on the saddle. "Normal" alignment is for the test bar to point slightly upwards & towards the toolpost (slightly being around 0.001" per foot). The test bar set between centres can also be used to set the tailstock for parallel turning, though a test bar of the tailstock socket taper is required to check the actual tailstock alignment. At a pinch, you could go for a 2MT test bar to fit the tailstock & use a 2-3 sleeve to check the headstock, though adding the sleeve also adds a potential source of error.
If you want to start throwing money about, a test bar would be a better place to start than changing out the bearings initially IMO - you could recoup much of the cost by selling it on later if you felt you no longer needed it after use.
|Thread: EMCO FB2 electrical help|
The Emco FB2 Operating Instruction manual & Spare Parts List can be downloaded **LINK**
The manuals are in German & the Operating Instruction manual (Betriebsanleitung) has wiring diagrams.
|Thread: Motorcycle General Discussion|
I can feel a bit of a shock but not enough to generate a spark
Might be that the flywheel needs remagnetising, rather than the condensor ?
|Thread: Soft start|
Plenty of cheap thyristor speed controllesr / dimmers on Ebay :
2Kw rated 192410752118 £1.23 delivered
4Kw rtaed 192410975598 £2.85 delivered
5Kw rated 192441295326 £4.69 delivered
I have used the 2Kw type to reduce the speed of pistol drills - put the module in a small diecast box wth a 13A plug on one end & a trailing socket on the other, so it could be put in circuit as required. Worked fine for my intended use, though for yours you would have to manually ramp up the speed with the pot.
|Thread: Imperial acme threaded rod|
If Abssac can't supply, this company **LINK**
were recommended by John Stevenson when this topic was discussed some time ago on this forum. If you go the download page, the standatrd screw products .pdf lists 1/2" 10 tpi LH and RH as stock products.
Edited By mgnbuk on 03/05/2018 16:09:56
Abbsac still list this as a "legacy product" **LINK**
Might be worth a call ?
|Thread: The Workshop Progress thread 2018|
I'm not sure if a lathe boring bar will work as they tend to set the tip at an angle
Can't see why it should make a difference ? If I use the boring bar in the lathe (set correctly on centre) to machine a bore larger than the minimum specified for the tool in a rotating workpiece, or rotate the same bar set on centre in a boring head to generate the same diameter bore in a stationary workpiece, the tip is presented in the same way to the bore regardless ?
I have used larger diameter lathe boring bars in larger than ME size boring heads at work (admittedly into graphite components, not metal) & they have worked fine without rubbing, and have also mounted lathe internal screwcutting tools in milling chucks & using them as fly cutters for thread milling on CNC milling machines.
I have the bars I linked to & intend to try them in my 2" boring head - just require the 1/2" to whatever reducing sleeves making to be able to try them out. I'll report back after doing so, though these projects do seem to take longer than initially anticipated !
How about one of these Ebay 352259180098 & turn it down from 10mm to 3/8" ?
Also available in 6, 7 & 8mm diameter taking the same CCMT0602** inserts to sleeve up. Searching "SCLCR" brings up most of them.
|Thread: Warco WM250 Lathe and Warco WM18 Milling machine (Advice please)|
We get a lot of raw material & finished parts from China at work & very rarely do the containers turn up "on time", due to many factors. The source factory can be late shipping, ships get delayed by weather (we have had containers delivered to Rotterdam instead of Felixstowe due to weather, then lost 3 or 4 weeks getting it back from Rotterdam to Felixstowe again). Even when your container does get into the UK, some get impounded at random by C&E for X-ray checking, which can take over a week (for which you are charged storage by the day !). And rarely can the shipping agents give any kind of delivery update until the day the container is actually released to them at the port.
It is not good for the blood pressure when you have "late" parts that have to get to customers to keep production lines running & you don't know if they will get to you on time. 4-6 weeks "late" from intial estimates given 3 or more months previously is not unusual & no amount of huffing and puffing on our part will get "late" shipments to us any quicker - it arrives when it get here & not before !
I enquired about a WM18 with an MT3 spindle recently (not currently shown on Warco's website - they seem to have standardised on R8) & was told that one could be special ordered no problem & delivery would be the normal 5 months - it is a long supply chain ! So it is quite likely than Warco got an estimated delivery date at the time they placed their order several months back & genuinely don't know when the container will actually turn up if it is "late".
And Warco are not alone in this - SPG are OOS of their equivalent milling machine at the moment - the answer to my restock query being that delivery "should be next month". It must be just as frustrating for suppliers not to have stock to sell & not knowing when it will appear (due to circumstances beyound their control) as it is for you as a customer - you could try cutting them a bit of slack.
|Thread: Mobile Networks|
Does anybody still do a real Pay As You Go?
Yes - I use Virgin for both landline, internet, TV & mobile. As a landline user, they have a lower rate for PAYG (8p/min & 8p texts, with free Virgin - Virgin calls & texts). I top up £20 every 18-24 months (no time limits).
I did have a data only contract tablet with EE. It worked reliably enough in the UK, but was useless abroad. Getting EE to cancel the contract at the end of the signed-up period was made especially difficult by EE & I would not choose to use them again. Currently have a pre-paid 3 data only Sim for the tablet - £27 (IIRC) for 24Gb over 2 years & works equally well home or abroad.
|Thread: Glass-scales-ZX45-RF45 clone|
Y-axis scale mounted at the rear of the table leaving the front clear
In normal industrial parlance, that is the X axis (table left-right movement) - the Y axis is the table front-back movement.
Nice installation, with the table scale in the "optimum" position nearest the fixed dovetail (opposite side to the gib strip) . I am currently looking at a 3 axis DRO for my FB2 clone & it oden't look like I have enough room to put the scale at the back of the table without restricting an already short (140mm) Y axis travel.
|Thread: Aldi 3 drawer steel toolchest|
Bought one of these **LINK**
along with the shopping this morning.
While not super high quality, it seems reasonably well made. It was well packaged & undamaged when unpacked. The outer chassis & lid are approx. 0.8mm steel, with the drawers being approx 0.7mm. All drawers & the top area have liners, with the first drawer being segemented for small parts or tool storage,
A drop-in bar secures the drawers when the lid is closed (the bar is in it's "parking" position on the left of the picture - it locks the drawers when inserted in the slot at the back) & two keys are supplied for the lock. Not sure why there is a "mousehole" in the back wall on the right - any ideas ? Finish is satin red & appears well applied. According to the Aldi link, black units were also available, though my local store only had red.
Another step towards organising the garage / workshop & reasonable value for £40. At the time of writing, these are still available to mail order from the Aldi website if you don't have a local store or they are OOS.
|Thread: Aircraft General Discussion|
Or, given Sam's location, possibly CAC Wirraways.
|Thread: Warco WM250 Lathe and Warco WM18 Milling machine (Advice please)|
To check if the quill is perpendicular to the table, proceed as follows :
Fully extend the quill and clamp it.
Then repeat the process, but with the dial gauge set on the side of the quill & "wipe" it with the Y axis (table moving front - back) rather than the X.
The readings "should" be pretty well the same top & bottom from both setups - my guess is that the side value will be close & the front value will be out.
|Thread: Where to get a running bearing for Ajax AJ8 mill|
1 1/2" Od x 1 1/4" Id x just over an inch long hardened & ground inner bearing ring.
Press or glue 2 onto a 1" bore x 1 1/4" Od sleeve & away you go.
Quite a range of Imperial bearing inner rings readily available - precision ground hardend parts at reasonable prices
What about using needle roller bearing inner ring(s) ?
May need to use more than one is series, but I don't think that would cause problems.
|Thread: Anyone fancy a larger UK made milling machine?|
Seriously, do they normally machine steel dry,
Yes. IIRC one of the reasons being that the inserts need to be kept at a fairly constant temperature, so coolant needs to be a very strong flood. This is not always possible & is difficult to both guard & collect. Intermittent application of coolant to hot inserts can lead to failure due to thermal shock. Again IIRC, the idea is that most of the heat goes into the swarf, but I have regularly come across operators keeping a pair of welding gloves to hand to change tools, as the tool bodies can get hot enough to burn you. Insert drills, though, need high pressure through-tool coolant to blow the chips out of the hole - that really does go everywhere !.
the Mandelli factory in Piacenza in the late 1980s, they were capable of such work rates that it was refrigerated before re-use.
That may have been to keep the workpiece cool to maintain tolerances. I have seen some machines that use temperature controlled coolant circulated through the machine to keep the machine structure cool for that reason - including through hollow ballscrews via rotating unions. As Mandelli were manufacturers of quality boring machines, I would expect that they took dimensional accuracy of parts seriously.
I'm not sure that the "UK made" bit is true anymore - pretty certain they announced in the trade press that they were not going to be building their own machines here anymore & were going to be concentrating on the agencies a couple of years ago.
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