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Member postings for mgnbuk

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: Titanium Wire
22/11/2011 21:11:16
I get several unsolicited e-mails every week from Chinese suppliers of titanium in various grades & forms - happy to forward a few if you wanted to approach one (or several) for a "sample".
Thread: metric taps
22/11/2011 21:04:25
Guess I've got strong wrists as I've been using dia-pitch for 30odd years ever since that was what I was tought and seldom break a tap

Ditto. Well, except for the strong wrists bit (Carpal Tunnel decompressions both sides !)

I cannot recall seeing any instances of "oversize" tapping holes being recommended on manufacturing drawings - the "Thread diameter minus pitch, rounded to nearest standard size" rule seems pretty universal.

Thread: SMW Autoblok/ Rohm
12/11/2011 16:05:46
The smaller Gildermeister "Manual Plus" CNC lathe at work has a 315 dia.manual Forkhardt 3 jaw chuck - we priced up a replacement earlier this year & it was about £3,100. I'm not sure what jaws (if any) were included with that. The Forkhardt chuck doesn't use a scroll, having a screw operated moving block that rotates a plate the drives the jaws through a limited stroke. The jaws are serrated & can be positioned to suit the diameter of the workpiece. If our operators would grease the mechanism regularly as instructed, then the expensive screw & moving block would not strip !
 
While waiting for the parts to repair our chuck, we bought a Chester 315 dia. 3 jaw scroll chuck off Ebay for less than half the price of the replacement screw & block (£1100 for the parts, £430 for the Chester chuck IIRC).
 
The Chinese chuck is suprisingly well made, but it's 2-part jaw interface (tenon / slot arrangement) is the opposite "polarity" to the Forkhardt, meaning that our extensive collection of soft jaws won't fit - hence the quote for a new Forkhardt chuck.
 
We also bought a 500 dia. Chester 3 Jaw scroll chuck for the large Gildemeister lathe- the jaw tenons on that are identical to the 700 dia. 4 jaw that came with the machine. That is also a well made chuck that cost around a fifth of the price of the next cheapest 500 chuck I could find.
 
HTH
 
Nigel B.
Thread: MEW, would less be more?
06/11/2011 16:03:19
I agree. The current 13 issue arrangement provides no more "content" than the old 8 issue arrangement, but includes far more advertisements - most of which are of no interest & of little relevance to me.
 
I have not not happy with the current content/advert ratio for some time now and, as I see no chance of any change for my idea of better, I cancelled my DD subscription a couple of issues ago.
 
I guess you can't please all of the people all of the time though, as I have subscribed since very early on (and have all bar a couple of early issues), it is a shame non the less. I stopped getting ME many years ago, as I have no interest in steam models or railways - maybe time to have another look at HSM ?
 
£0.02
 
Nigel B.
 

Thread: My Super-7 trips out
05/11/2011 15:57:55
Check that the current rating on the overload matches the motor full load curent on the motor rating plate. The overloads have a working current range that is adjustable, but setting to "maximum" may still trip if the overload maximum is less than the motor. The overload should be adjusted to the motor current & no more.
 
If that is OK, I would use a clamp-on current meter to check the current that the motor is drawing. If it is at or over the motor rating plate FLC, I would remove the input drive belt & check again. If still over current, have the motor checked out. If it is now under, how tight is the spindle drive line when rotated by hand ?
 
You don't say what speed range you have the machine set to, but if it is one of the higher ranges it may be that your spindle front bearing is set a bit tight. I run my S7 from an older inverter - my front bearing is set close enough that it won't start at the top couple of speeds (inverter trips) unless it has been "warmed up" for a while at a lower speed.
 
HTH
 
Nigel B.
Thread: Ground angle tool checking device
01/11/2011 19:16:27
Would something like this do :
 
http://www.swissprec.com/CGI/ISPDFF?PMCTLG=01&PMPAGE=96
 
The current J&L offer flyer landed on my desk yesterday - IIRC the basic 7X unit with a standard recticle is under £30, with the extra reticles around £9 each.
 
Nigel B.
Thread: RF30 Mill/drill replacement belts
28/10/2011 16:42:31
I have had a Taiwanese built "Tru-Tool" RF30 mill/drill (appears to be the same as the Warco Major) awaiting commissioning for a number of years - the main hold-up being it had a 3 phase motor and the intended fitment of an inverter was constantly slipping down the list of priorities.
 
But a Machine Mart Vat-free coupon was recently utilised to obtain a Clarke phase converter , which got the machine running - though rather lumpily. The poor running was traced to the original Vee belts having taken a set & the wrapping was coming away in places. As the original markings were quite clear ("GeminiRope" B42 and B34) I got replacements from my local bearing supplier.
 
They didn't fit - both being far too long to allow tensioning once fitted. When the original belts were measured, they turned out to be B40 and B32 respectively.
 
Whether the originals had been mis-labled, or the Taiwanese use different belt length standards to everybody else, I don't know. But I do vaugely recall having similar problems with a Sealy 12 speed pillar drill where I used to work some years ago.
 
I chose to fit more modern raw edge, moulded cog belts (BX40 & BX32), which fit well. I have yet to connect it up & see if the running has improved, but the drive arrangement does turn more smoothly by hand than before.
 
So if your imported machine requires replacement belts, it may be best to ignore any markings & have the originals measured to get the correct size.
 
Nigel B.
Thread: Collet Chuck
28/10/2011 16:23:41
I had thought I might be able to assist with these, as I have a box of similar shape collets that came from a scrapped automatic capstan lathe.
 
But when I dug them out today, while they are the same nominal shape they are different dimensions - overall length is 2.531", the ground end opposite the taper is 0.471" , the parallel section ahead of the taper 0.498", taper max dia. 0.734", taper min dia. approx 0.485", taper length approx. 0.451".
 
I cannot recall the make of lathe, but seem to recall that the collets were refered to as "dead length collets" - i don't think that the length of material protruding changes as the collet is tightend. The collet chuck on this machine was either pneumatically or hydraulically actuated & there was a bar feed fitted.
 
It seemed a shame for all the tooling that accompanied the machine to follow it into a skip, so the collets & few other bits were "rescued" - but a suitable holder / clamping arrangement for my S7 has yet to be designed.
 
Nigel B.
Thread: Anyone have a Worden grinder? Experiences?
27/10/2011 07:45:07
The Worden has stops fitted to the cross bar
 
Mine doesn't - the snail cam modification to the table tilt arrangement meant the original stop design wouldn't work. The original builder didn't come up with an alterative stop arrangement to work with the snail cam. I only realised that it should have had stops when I got a set of original drawings - I guess that's another project !
 
I think a linear bearing will suffer from dust penetration, so far I have had no problem with the cast iron block binding.
 
The ball bushings do at least have wipers to help keep grit out. As the two complete ex-equipment bushes & hardened rods cost nothing but my time to remove them from their original installation, I have little to loose trying them. Should the bushing life prove short, Igus manufacture plastic lined bushings designed to run dry that are dimensionally interchangeable with standard ball bushings. I had intended to add an oil seal at each end of the bushing as an additional wiper - might add a bit of extra drag, but it won't be as bad as the "as designed" arrangement. If your machine has the guide bar at the rear, you won't suffer the grit problem that causes my front bearing machine to get stiffer with use.
 
Nigel
26/10/2011 20:35:17
moved the pivot to its current (front) location as an "improvement". I've asked around but could never discover the reasoning for that.

I have an early version with the pivot at the front - bought competed at a Myford Open Day several years ago. It looks like it was assembled in a bit of a rush (or by someone learning the ropes) as it was unpainted & some areas of machining were a bit "rough and ready".

I have not used it much, but it does a better job of grinding lathe tools than I can accompish by hand. It has had a modification done to the table tilt arrangment - a snail cam instead of a curved, slotted strap and lock screw. I was only made aware of this when I came by a set of the original construction drawings. I can only guess that the original builder found the as-designed arrangement lacking.

One of the reasons it hasn't been used for much more than lathe tools is (IMHO) probably the reason for the change of table bearing arrangement. The front-mounted bearing gets covered on grinding dust and gets very sticky in operation. This isn't a problem when doing lathe tools, as the tool is swept across the face of the wheel, but I wouldn't want to try doing the end face of an end mill trying to avoid overshooting & catching the opposite tooth. It also doesn't have the angular markings on the table top, so I use a combination set protractor to set the angles.

I have (just another project !) a linear ball bushing & hardened shaft to fit in place of the original close-bored cast iron on mild steel arrangement. Hopefully this will give a bit more "feel".

I am happy enough with it for the £75 it cost me. I'm not sure I would spend upwards of £400 on the kit, though.

Nigel B.
Thread: ER32 Myford Collet Chuck
26/10/2011 20:16:43
First I assume you are not intending to lap the spindle ? ( just checking!)

I will freely admit to being a bit daft on occasions, but I'm not that daft !

I would think long and hard before you resort to lapping.
 
I had a closer look & a measure-up this evening. The collet chuck body starts to go on the spindle, but goes tight with around a 5mm gap to the spindle register face.
 
My Super 7 is a mid-60s built, ex-school machine that doesn't appear to have had much use * - the original rust preventative was still present in the spindle taper & the spindle nose appears as though "just ground". The register measures around 1.2499" as near as I can read a Starrett 0-2" mic that zeros correctly against it's 1" standard - that is visbly under 1.2500", but by barely the width of the fiducial line. The register appears parallel along it's length.
 
Using an M&W telescopic bore gauge & the Starrettt mic, the collet chuck register bore appears to be around 1.2505" diameter. By feel the bore is pretty parallel. Comparing the gauge set in the collet chuck with the 3 jaw chuck backplate bore, the backplate is a very slightly tighter fit.. As the collet chuck goes tight before the apparently big enough, apparently parallel bore has seated, that suggests to me that the problem is with the thread.
 
Looks like I have the perfect excuse to "invest" in a Myford nose thread tap !
 
Nigel B.
 
* It must have had the chuck changed at some point in it's life though - there is a "chuck jaw end " shaped ding in the rear shear close to the chuck. Butterfingers !
 
Reminder to self - always use the chuck board !
26/10/2011 07:52:06
I bought a Soba one to fit my Myford
 
I bought one of those at Harrogate - don't know how good the runout is as it doesn't fit the spindle register (too tight). Finish doesn't appear too bad, but I have not had the time or inclination to lap the register to get it to fit on the machine.
 
I suppose it is better to have it a bit too tight than loose - at least it should be possible to get a good fit with a bit of effort.
 
Nigel B.
Thread: Moving a Boxford shaper
26/10/2011 07:45:28
Mine was delivered by the local dealer who I bought it from. He arrived with an engine hoist alongside the shaper in the back of a pickup & used that to unload the machine & place it in my garage. I used 3 or 4 steel bars (1 1/2"ish diameter) as rollers & a crowbar to move it into it's final position. It was moved a couple of times - in to position to mark the holding down bolt holes, out to drill the holes, back in etc. Finally grouted in after levelling.
 
It was some years ago that this occured, but I don't recall having any particular problems - I had a reasonable amount of room to work at the time. As with all cabinet mounted machines, it is top heavy & should be moved with care - slightly off-balance & it would fall over very quickly (as I found out later with a CUD lathe - fortunately without any damage to self or little damage to the machine !).
 
Nigel B.
Thread: Mill Gearbox Lubrication and cutting oil
11/10/2011 19:49:17
Anybody have an opinion?
 
Well - from experience with lubrication of gearboxes in "full size" machines I would suggest hydraulic oil would be a good place to start. More machines that I have come into contact with have used hydraulic oil to lubricate spindle gearboxes than any other type of oil. I seem to recall the odd one that used slideway oil & one (a Brown & Sharpe VMC) that used ATF, but non spring to mind that specified a gear oil.
 
Viscosities vary - and some of the bigger machines use the lighter oils. Most large vertical borers (Webster & Bennett, Schiess, Froriep, Morando, OM) specify 32 viscosity oil. The Gildermeister lathes at my current workplace specify 46 viscosity hydraulic oil for the spindle boxes, as does a Kira VMC. A Dixi CNC borer I once worked on used 10 weight oil - like water ! I have seen the gears on vertical borers (I used to work for a CNC machine tool rebuild company) that had done over 20 years service (37Kw motors usually) that still showed the original grinding marks on the teeth, so ISO VG32 hydraulic oil seems to provide sufficient lubrication.
 
I don't have any experience of piston compressor oils, but suspect that they would be optimised for constant high temperature operation - maybe over extended periods. All piston compressors I have worked near have run hot. I suspect they would have similar characteristics to monograde engine oils.
 
My first preference would be to use a 46 viscosity hydraulic oil, but if no industrial suppliers nearby, then use ATF. I use ATF in the head of my Taiwanese Emco FB2 clone. ATF & hydraulic oils have added extreme pressure & anti-foaming additives and good viscosity stability with temperature change (think of the lubrication requirements of gear or piston pumps). Lighter weight oils will give the motor an easier time at start-up - higher viscosity may give better noise damping (maybe the reasoning behind a recommendation for 68 viscosity).
 
Other opions will, no doubt, be along in a momemnt !
 
Regards,
 
Nigel B
 
Thread: Myford collets
07/10/2011 17:55:08
What sort of T.I.R. did you get with those ER25 collets.


I bought a 2MT ER25 collet chuck & a set of collets from Ebay seller "onlineseller68" in Hong Kong. The collets came in blue & yellow boxes similar to those that Arc Eurotrade supply. Delivery was a couple of weeks. I can't recall the total price now, but IIRC it was less than half the price quoted by the UK retailers.

I checked runout in my Super 7 spindle on a 10mm carbide endmill held in the appropriate collet - runout measured on the tool shank close to the chuck was the same as I measure on the front of the taper in the spindle nose at around 0.0002" TIR
 
That is close enough for my requirements !
 
HTH
 
Nigel B.
Thread: DRO on a Mill/Drill?
28/09/2011 19:50:03
the backlash on the x-axis is about 1mm from memory
 
I have a Taiwanese made, "Tru Tool" branded RF30 that appears to be identical to the Warco machine. That too had a lot of lost motion in the X axis when I bought it second hand. It turned out to be the two bolts holding the nut bracket to the saddle were loose, allowing the nut bracket to move through the hole clearance. No pins or tenons are employed to take the thrust, so if the bolts loosen the bracket can move.
 
Regards,
 
Nigel B.
Thread: Parts for Bantam Lathe
28/09/2011 19:42:51
I missed the bit in the original post that said that the OEM had the parts available but that they were too expensive

Machine tool parts are always expensive - industrial machines particularly so. But the manufacturer can still supply the parts you require for your 40ish year old machine & they should go straight in, be made of the originally specified materials & to original tolerances & accuracies. The thread will most like be thread milled or thread rolled & may have been ground & the nut threaded with a special tap that initially roughs the thread undersize then finishes it (think of two taps joined together axially, with the first being a bit undersize & the thread being continuous).

As you say, there are cheaper options. WMH & Raine sell rolled acme screw stock by the metre in various sizes, leads & both hands. Bronze nut blanks to suit also.

Depending on how worn your screw is you could re-cut the thread to remove the wear & make a new nut to suit the re-cut thread - minimal outlay with that route (you could do it on your machine by locking the cross-slide & using the compound suitably positioned) & one used by a machine tool refurbishing company I was seconded to during my apprentice days.

Regards,

Nigel B.
27/09/2011 13:25:53
Have you tried Colchester ?
 
Spares
Tel: +44 (0) 1924 412603
Fax: +44 (0) 1924 415008
Email: spares@colchester.co.uk
 
Regards,
 
Nigel B.
Thread: How to tram a mill
16/09/2011 15:43:18
Firstly, I wouldn't use a drill chuck, they are generally not accurate enough A collet directly in the quill, or a collet chuck would be preferable.
 
Why ?
 
Whatever method of holding the DTI on an offset rod arrangement in the spindle to measure the misaligment of the spindle axis to the table will not affect the result - the attachment arm is clamped in the spindle regardless.
 
Don't run the DTI directly against the table top, but interpose a ground block between the two. This way the DTI doesn't rattle over the Tee slots - position the DTI & carefully slide the ground block on the table top under the plunger (set the DTI to give around half a dial rotation only so the block slides in easily). I use a roller from a large roller bearing 1/18" dia. x 1 1/8" long - with nice radiused corners it slides in gently & doesn't knock the DTI - but a slip gauge or ground parallel will do just as well. Take the reading, slide the block out, rotate the DTI & repeat. Always re-ckeck your intial position to make sure the DTI han't been knocked. A small mirror makes taking the rearmost reading easier - but be wary of getting the sign wrong !
 

Thread: degreasing
12/09/2011 13:32:18
DEB Janitol Rapide diluted around 4:1 with water.
 
Apply witha trigger squirty bottle & agitate with a stiff brush. Re-apply as required.
 
As this is a caustic product, wear gloves & eye protection. I generally wipe off & dry with paper towels.
 
This works very well on coolant residues - at my previous employment (CNC machine tool rebuild & retrofit) we went almost exclusively to water base caustic cleaning solutions as they worked more quickly & more effieciently than solvents & didn't cause much paint damage. Currently using the DEB product to clean machines bought at auction before starting to use them in production (machining exclusively graphite - sticky, oil surfaces attract the dust).
 
Caustic multi-surface kitchen cleaners probably work as well & available in ready-to-use bottles from supermarkets - I generally have a bottle of Mr Muscle glass cleaner in the office for cleaning monitors etc. and it is effective when used for other small cleaning small jobs. A bit expensive for the bigger machines, though.
 
Be wary of gunwash - nasty stuff, gets into your system through your skin even when wearing gloves. Also highly inflammable with a low flashpoint. Meant for cleaning painting equipment & best reserved for that IMHO.
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