Member postings for Chris Hembry

Hi Tristan,

Welcome to the DT Technician club!

I was in a similar position to you a few years back, and am now in the pleasing situation where all the machines are up and running. I was fortunate in that I learnt my initial skills at the same school, on the same machines nearly 40 years ago.

We have three Seniors, an identical M1, a LV and a M1 Horizontal. All fully guarded and available to the upper school to use.

As has been said, DT is now much more about teaching the processes available by demonstration rather than the old hands-on approach. Am not convinced it does the kids any favours whether they go into industry or not, but contact time or budget just does not permit anything else.

Have sent you a pm with school email if you need any info.

Regards, Chris

Yes I run a 2A in my shop. As you suggest they are very heavily built.....but, as others have said, they are production machines and of no use whatsoever for general hobby use. There is no provision for threading, the leadscrew is driven by a flat belt from the spindle, so there is no guarantee of registration between passes. The cross slide also has a very coarse screw, so fine cuts are not easy to dial in. They are designed to use the turret for all cuts using die heads and roller boxes, the cross slide is for form tools and parting off to a depth stop.

Chris

Can't help directly with the Warco 712, but I have had the Axminster version for several years. It is used for production work cutting up to 50mm hex stainless using Tuffsaws M42 blades. Lost count of the number of cuts it's done but it will be approaching 10k.

Only had two issues: The quick release vice was junk, it wouldn't hold anything after about a week, so a quick rebuild with a trapezoidal screw and brass nut fixed that. Recently, the downfeed cylinder gave up the ghost, but again a quick repair with a new piston and O Ring has transformed it.

I've also had a 6x4 saw for 30+ years, but it just doesn't have the weight on the blade to cut the stainless.

Chris

Hi John,

I can't see any holes in the main shaft, but there is a ball oiler on the back gear and also a grub screw on the main shaft pulley. This grub screw is 5/16 BSW.

Neither of the machines here have oil holes on on the front of the saddle other than ball oilers for the slides. There is a 1/4 BSW hole tucked away to the right hand end of the table stop tee slot, but not sure whether that is for oiling.

Regards, Chris

Hi John,

Can't help with 1 or 2 until tomorrow, but for 3 - yes, you should be able to. Just doing a countershaft rebuild at the moment, and the grub screw holding the double pulley on to the shaft on the inside should bear down onto a slot in the shaft. So loosen this screw and tap the pulley to give the required clearance.

Regards, Chris

Which is why I specified a three phase EStop so all three wires are broken together. Or use a contactor, with a 24V coil fed from the inverter control circuit to give another protection level.

Of course you are free to do what you want on your machinery, but I prefer an EStop to actually guarantee to make a machine safe rather than just in theory.

This stems from an instance when a machine had a dangerous but rare tendency to start on it's own because the inverter picked up a stray signal from the spindle encoder when the chuck was moved by hand. I lived with it for a short while, but there was no way I was going to let anyone else anywhere near it !

There is a STOP for normal use, and EStop for emergency use, hopefully never ! One uses the inverter to brake, the other doesn't, just in case it is the inverter at fault.

You don't need a larger inverter than you would have specified anyway since you are not looking to ever have to use the EStop. As said above I'd rather buy a new inverter than lose an arm !

Chris

I seem to be in a minority here, but I would always recommend the EStop being between the inverter and the motor.

The EStop is your last line of defence should you be stuck in the machine...the last thing you care about is whether it damages the inverter !

It is true that the inverter CAN be made to stop the machine more quickly than just disconnecting the motor, but what if the inverter itself is at fault ? And what if the only person able to operate the EStop does not know how it is wired ? The only thing that matters is that it MUST make the machine safe.

There must be no stop switches on the Input side of an inverter except to electrically isolate it for maintenance. As others have said, the inverter will continue to run until the DC bus has dropped low enough for the inverter to trip out.

So, what to do ? - Fit a normal Stop button that operates the control circuit on the inverter (programmed to stop at whatever speed you wish). This is for NORMAL operation and should not have the big red mushroom head. Fit a three phase, normally closed, latching EStop switch with the mushroom head between the inverter and the motor. You could use a control contactor instead, and have that energised only when ALL safety devices have been proved to be in place (this is the usual method on machinery).

Regards, Chris

A bit expensive, but we use this type on our Senior mills at school :

https://www.technologysupplies.co.uk/milling-machine-guard-m1.html

Must be other ones around for less. They mount directly onto the tee slot at each end of the table and can rotate right around that axis.

There never was one, only document was an sales/operating manual covering the ML1-4 lathes. Download available from several sources.

It all depends on the model that the company uses for spares pricing. Some companies will heavily discount the original product in order to generate sales, and then attempt to recoup that with the cost of spares. Large machinery producers regularly use this technique, think combines, tractors, trains and lathes !

Bear in mind that when the lathes are originally produced, a number of parts that are deemed to be consumable will be stocked as spares. These may well be reasonably priced. However, not all parts will be kept in stock, so you will be charged a one-off or small batch price for the component to be manufactured for you, if they even offer to supply parts for obsolete models

Can't help with identification, but I also have a set of castings for this compressor. Only difference seems to be that mine has a 4 spoke fan/pulley. Had the parts a long time but think they were a one-time student project.

Simples : It's not a 1:1 ratio. While the turret rotates 1 position at a time, the stops can rotate either 5 or 7 positions making the gearing much simpler

Hi Martin,

An odd place to fit a DRO arm, but not impossible...how about a one-shot oiler system ?

Either way I doubt it would cause any issues.

Regards, Chris

Don't worry Peter, already in contact with Bill over the missing parts. Drawings done previously for a previous customer who didn't get the full set of spares with his machine.

Regards, Chris

Hi Bill,

To add to what Peter has written, it may be worth adding that the friction drive involves using two parts to replace a pair of gears. If you are missing gears, it is likely you are also missing these components. As a fellow 220 owner, I'm sure we can come up with a solution as you will be unlikely to get any help from Warco.

You should have the threading chart on an aluminium plate attached to the inside of the changewheel cover. The manual gives a straight copy of that.

Z is a common designation for number of teeth used in Germany, Bulgaria etc.

Regards Chris

I have a Chester Super Lux...no issues with accuracy or finish. Also have a Warco lathe....the famed aftersales service has never materialised as all emails have been ignored. Just my experience !

I've tried several different sources of inserts and have to say that in future I'll stick to named manufacturers. Those supplied by third parties without naming the manufacturer MAY be ok, but there is no guarantee that they always will be since they are free to change supplier at any point. I'll stick to using Sandvik and Korloy for production work.

Welcome Carl, also a couple of air rifles here and another ML4 in the queue for a rebuild. Not quite sure which direction to take it yet, might yet be CNC.

No problem Mark. By choosing a gear head mill, you've already solved the torque issues that the 20vs will suffer from. The normal drilling capacity of these machines is 45mm with 1hp, and I can say that it manages this in steel all day if you want it to.

I'm sure Chester would fit a 3 axis DRO for you if you asked.

Personally, I can only see the powered spindle downfeed being really useful on boring head jobs, whereas the head elevation is used on nearly every tool change. To have both would be a nice feature, but I would not have spindle in place of head.