Member postings for Nige

I would guess to prevent people who just want to sell stuff using it as a selling site. I think the Classifieds section is an extra for Forum members and users, Just guessing of course.

I wanted to tap an M8x1.25 hole today. My only metric taps and dies are a cheapo set from goodness knows where which I have had for ages but never used. Firstly there was only a plug tap at that size in the set and when I looked at it the thread form was so bad that there was no way the leading edges were ever going to start or cut properly. I'm resigned to the fact that I will by sets of 3 taps as i need them and get better quality HSS ones as I can. Set of 3 PRESTO on order from an eBay seller at £11.

Nice job David

I was looking at setting the Sieg lathe up to cut a 12 tpi thread and decided to use the method I was taught at school and to angle the compound slide to half the included angle of the thread and wind on all the cuts from there. As this is a Whitworth form thread that gives and angle of 27.5 degrees. To achieve that the compound slide has to be rotated clockwise (looking down on it) 62.5 degrees.

Two problems immediately arose. One- The slide would only rotate about 45 degrees and then something was stopping it. On investigation I found that the head of the backlash adjustment screw under the compound was catching on one of the bolts seen in the photo below.

The answer was to remove the screw and gently file about 1.5 mm from the thread. This leaves ample thread for further adjustment and gets the screw to just clear the bolt head. Below the offending backlash adjusting screw.

Problem Two- Once you rotate the compound round to about 45 degrees you can no longer see the witness mark against which the angle is usually set as it is now hidden under the compound! What is needed is a second witness mark round to the left of the compound against which the angel can be set. Question is what is the best way of making the new mark, maybe a centre punch mark or a scribed line of some sort, if that how please ?

Edited By Nige on 30/06/2018 19:59:40

Just a heads up about the power feed handle for the saddle and cross slide feed. It is VERY EASY to go straight through the neutral position and straight into the cross slide power feed position when disengaging the saddle power feed as I have found out AGAIN. This happened even though I had practised the gentle movement required and knew the possibilities !!! Fortunately it didn't cause too much damage to the work piece as the lathe stalled as the tool dug in and I was able to get the E. Stop hit.

Some possibly useful info here :

**LINK**

From what I can see of the motor plate it appears to be a single phase motor as it appears to be a 220V 3.9A device though a search on the motor type number might help. A better picture of the motor plate would help Dennis

Nige

I went back to my rusty bolt last night. The first photo shows how I set it up and I made it as concentric as I could measuring outboard of the steady. You can see the ring of oil where I first closed the steady up, with it as close to the chuck as possible, before moving it to the position you can see. I used a 1 thou feeler gauge to leave me a little clearance in the steady and kept it oiled. I ran the lathe at about 200 rpm and had no untoward noises from either the work or the steady then drilled into the end with a centre drill.

I then put a revolving (live?) centre on the end and set about machining the thread off. The interrupted cut didn't cause any vibration of nasty noises. The tool is an HSS one I ground and tarted up before I started and I was only taking 0.1mm cuts. The steel didn't appear at this point to be too hard but it was difficult to tell with the interrupted cut.

Once I had removed the thread I turned the bar in the lathe,checked it wasn't too far of concentric and centre drilled the other end. Once the end was centre drilled I removed the steady and supported the end with the live centre again. At this point It would have been better I think to have been able to turn between centres but I don't have a face plate or drive dog and couldn't think of another way of holding it.

This time I was working on the 'naked' outside of the bolt. I had been warned by a friendly phone call that the outside 'skin' of the bolt might prove to be hard, tough, horrible to turn (pick any or all that apply) but in the event I wasn't able to recognise too much that was horrible about it though the surface was looking a little rough. However, a resharpen and honing of the tool improved matters though it might well be that by the time I got to that point I was through the rubbish outer layer and on to nicer steel.

I got bold with my DOC and wound up the speed to 400 RPM and 0.2mm of cut. I know. not really a lot but I did get some nice dark blue swarf chips So that is how it sits at the moment, next move is to try and improve the surface by changing to maybe a rounder nosed HSS tool and then trying a Carbide tip and winding the speed but would appreciate any thoughts on that.

Inspection of the bronze supports in the steady showed no damage and just a very slight bur which is no surprise really considering the state of the surface of the piece though I had attacked it with emery paper prior to mounting it all up.

The battery would have been 50V Dave but with and ampere hour capacity in the area of 200 Ah. The large exchange batteries I dealt with were a lot bigger than that at several thousand Ah capacity and each individual cell being approx 1 meter in all dimensions. At 25 cells to the battery and two batteries to a room the battery rooms were large to say the least. The old power plants 233 that fed those things became redundant with changes in technology that co located smaller AH capacity batteries in with the equipment. Previous policy had been to provide batteries to give a 24 hour back up at the peak hour rate. As telephone traffic patterns changed and technology changed policy changed with it and battery back up was dropped to 1 hour capacity and greater reliance placed on stand-by engine sets. Strangely enough as the technology got smaller the heat output got MUCH higher untll we were using more power to cool equipment rooms than we were running the equipment within them.

A power failure call out at 3 in the morning was a sphincter tightening experience as if the engine set hadn't started there was about a 1 hour window before exchange switching equipment stopped working ! Power and Building Engineering Service maintenance with BT was a really interesting time as until they were floated on the stock exchange we did all our own maintenance and didn't use companies or contractors for anything. We were very much multi skilled doing all the maintenance on Lifts, Heating and cooling plant, and the AC systems from the HV incomers to the last socket in the building plus the DC battery systems and UPS supplies; there was nothing we didn't do even to re-roping the passenger lifts in our own buildings. Fun times and I really miss them

I remember at some point in the 70/80s experiments were done using ‘Invar’ rails which had a much lower coefficient of linear expansion than ‘ordinary’ steel rails. I’m pretty sure Invar went into general use but don’t know how extensive it’s use became. I’m sure somebody who knows will be along shortly..... unless of course delayed by the heat 😊

As a Post Office Telephones apprentice back in the early 70s we were shown a video about the dangers of climbing poles while wearing rings and as a consequence in later years I removed my wedding ring while working on ‘external’ stuff. In later years when I worked on telephone exchange power plant rings came off or were taped over. Across many years as health and safety became more and more of an issue I had to learn to risk assess situations not just for myself but also for the people who I was responsible for and I still do to this day. A blanket No rings policy is fine for an employment environment where you have to try and remove risk because you can’t watch everybody all the time and you have to have covered your back but in my own workshop I know my left hand is going nowhere near anything that moves and could possibly catch on my wedding ring. We’re i to wear a ring on my right hand, as I do occasionally, it would come off. To this day if I work on a ladder or under a car bonnet my ring comes off 😀

Thanks guys. The whole point of this exercise is using what I have and learning the techniques to achieve the aim. Under ideal conditions it might be possible to choose a different bit of metal but the question would be exactly the same one if that was a nice looking piece of EN1A with the same dimensions. 😀

Thanks Rod and David for the suggestions on mounting and use of the steady 😀

Nige

I have this bolt about 1.2 inches in diameter and 7.2 inches long. As can be seen it has some corrosion mostly removable with a wire brush and file. I have cut the large square head off so have no 'true faces'. I want to reduce the diameter and cut a 12 TPI thread into it. I will probably lose the existing thread as this is to be a test piece. I initially mounted it in a 3 jaw with the intention of centre drilling the threaded end so I could then support it but as the Sieg mandrel is not big enough bore to accept the bolt I really have too much hanging out of the chuck. I then thought about using the fixed steady which came with the lathe but now I am in unknown territory never having used a steady. The steady is the type with 3 'pointed' bronze supports but the top doesn't hinge open.

I am concerned that the surface of the bolt may be too rough on the bronze supports. I'm guessing that setting the bar up in the steady is similar to setting it true in a 4 jaw chuck. Should I be using the 4 jaw chuck rather than the 3?

I could cut off the existing thread to shorten the bar but will still need to face both ends at some point and reduce the diameter to get it down to size for thread cutting and for turning the register portion behind the thread.

So, looking please for advice on the sequence of machining process's I need to face the ends, reduce the diameter and cut the threads.

Edited By Nige on 24/06/2018 20:22:17

Mmm, WARCO do a 150mm rotary table for £149 but I'm not experienced enough to make anything other than a 'cost' comparison though the Arc one certainly looks a more expensive job.

Just thought this might not be the right thread to kick off a comparison of rotary tables, would a moderator please move if necessary.

Edited By Nige on 24/06/2018 08:24:01

A word of caution when using the saddle power feed. It is VERY EASY to go straight through the neutral position and straight into the cross slide power feed position when disengaging the saddle power feed as I found today. This happened today even though I had practised the gentle movement required and knew the possibilities !!! Fortunately it didn't cause too much damage to the work piece as the lathe stalled as the tool dug in and I was able to get the E. Stop hit.

This is the first finished item I have made I think, a second chuck key for the 4 jaw: First thing was to mill the flats

Drilled the hole for the handle using the new support though had to resort to an unconventional way of clamping as I have finished the clamp plate or drilled the fixing holes for it

Finished Key. it seems to be a workshop rule that chuck keys have old bolts for handles

Very pleased with the result AND it fits

Gas_mantle: I have been watching a series of four videos on YouTube from DRO PROS about fitting a DRO to a mill very similar to the Siege and it does in fact appear to be a reasonably easy process.

Paul and Jason: Thank you guys

Jason: Thanks, I had spotted 2 holes behind the table but hadn't investigated any further.

I would appreciate thoughts about whether to fit a 2 or 3 axis kit to the mill. 2 axis is cheaper and I'm trying to think why or when the position in the Z axis is useful for anything other than drilling holes to a known depth which is already quite easy by hand with the digital vernier already fitted. Or am I missing something fundamental?

Edited By Nige on 21/06/2018 22:37:13

Part way through 4 part DRO PRO videos fitting scales to a mill on YouTube and magnetic certainly seems the way to go as you can cut the scales to size quite easily