Member postings for Rowan Sylvester-Bradley

My lathe (a Portass PD5) has a Brook Crompton single phase induction motor. I have two problems with it:

1. It won't start itself. When I turn it on nothing happens (except a faint humming noise). I can start it by hand, in either direction, but it would be nice if it would start itself. Is this likely to be the starter winding burnt out, or open circuit? Or is it likely to be a problem with the centrifugal switch? Or something else? If it's the winding, can I find the break and fix it, or rewind it myself, or get someone to do it for me? Who?

2. After a few mintues running, it shuts off. It's like it has overheated. After a few minutes it will start again. Is there some kind of thermal shutoff with these motors? If so, where is it? I'm not overloading the motor, it's very lightly loaded with the jobs I am doing at present. If it's not that, what could it be?

Thank you - Rowan

They look just like grease nipples, but since the label on the machine says " Mobil Vactra Oil Heavy Medium" presumably they are intended to be used for oil. I suppose there is no reason not to put oil into a grease gun that will clip onto the nipples?

I know any oil will be better than none, but surely it is better to use the correct sort of oil? Otherwise people would not make so many different types of oil...

Rowan

A related question: I also have a Qualters and Smith power hacksaw. Will the Slideway Oil 46 work well on the bowslide of the hacksaw? A label on the side of the hacksaw says to use "Mobil Vactra Oil Heavy Medium" for this Wiil the Slideway Oil 46 be OK for the slide, or do I need something different? They seem to have modified the design of the hacksaw mid life. Later versions have an oil reservoir and oilways feeding the slide, but mine is the earlier type that just has grease nipples.

Thank you - Rowan

Thank you for those answers - just what I needed.

Rowan

In my workshop I have three bottles of oil, all supplied by C Bennis Supplies and Services (who I can no longer find any trace of). The labels show the following descriptions:

"H32 Hydraulic Oil - Premium Quality solvest refined base oils, with four fold additive treatment". I think I have been using this to lubricate the plain bearings of my lathe. Is it suitable for this task? What is this oil intended for? Is there a better oil for my lathe bearings?

"1758 Neat Cutting Oil". I hoped that this oil would be usable to create suds as a coolant and lubricant for my lathe. But it doesn't seem to dissolve in water. How is this oil meant to be used? What is the best soluble oil to create suds?

"Slideway Oil 46". I suppose this oil is to be used to lubricate the slideways on my lathe. What is the best oil to use for this purpose?

Thank you - Rowan

Thank you for your suggestions. Some of these sound as if they would work for my project.

As someone previously pointed out, the holes don't have to as far apart as you have shown them. They can be moved in so that they almost touch the corner of the rectangular piece that fits into this hole, plus a bit to allow for drill wander.

Rowan

Yes, but I still need to drill small holes 30mm deep, and the problem of the drill wandering and not ending up in the correct position remains. I am gravitating towards milling the basic hole, and squaring up the corners with a specially ground cold chisel.

Rowan

If I am going to drill 2 mm dia holes 30 mm deep in mild steel, any hints on keeping the holes straight? If the drill wanders off, it will defeat the whole object. Should the drill be carbide, or HSS?

Thank you - Rowan

I can't see how. It is a tool that has to fit an existing piece of machinery, so I can't change any of the dimensions. I made it a blind rather than a through hole because I think I need the additional strength that this will provide.

Rowan

Thanks for your suggestion. Those would be too thick for the T-slots on my lathe (they need to be no thicker than 2.5mm). I suppose I could have ground them down, but in any case I would prefer a metric thread (to avoid accumulating too many different thread types on my lathe, which already has BSF/Whit and metric), so I think I will carry on making them.

Thank you - Rowan

I need to machine a rectangular blind hole in mild steel. It needs to be about 10mm wide by 20mm long by 30mm deep. It doesn't matter if it has slightly rounded corners. Is this even possible? What is the best way to do it? My current plan is to use an end mill (say 5mm) to make the basic shape, then use a smaller end mill (say 2mm) to square off the corners (if I can get a 2mm end mill that's long enough and stiff enough to cut 30mm deep). Will this work? Is there a better way?

Thank you - Rowan

I tried Spalding Fasteners. Their square M4 nuts are only 7mm square, so I'm now onto making them.

Rowan

OK. I was trying to avoid the hassle of making them just for a couple of nuts, if I could buy them for a couple of quid, but I have given up trying to find them and will make them as you suggest.

Thank you - Rowan

I just bought a small machine vice which was advertised as fitting my vertical slide. Unfortunately the mounting holes in the vice are too small for the bolts that I have that fit my vertical slide. I suppose I could try to drill out the holes, but I'd rather not do this until I've proved that he vice actually works satisfactorily, so I can return it if it does not. My screws are M5, I think I need M4 to fit the vice. I need M4 square nuts about 10mm square and about 2.5mm think to fit in the T slots in my vertical slide. Does anyone know where I can get these?

Thank you - Rowan

Yes, it has often been said that using an MT1 in the headstock was a design error on these Portass PD5 lathes. I will try with the MT1 extension that I have ordered, but if it seems problematic will move to an ER32 collect chuck on a backplate. Thank you for your advice.

Rowan

That sounds like a solution that might work for me. It needs to be an MT1 extension and I would need to drill a 6mm or 6.5mm hole for the M6 draw bar. I have ordered an extension and will have a go at drilling it when it arrives.

Rowan

Edited By Rowan Sylvester-Bradley on 01/04/2023 19:35:00

Are you saying that an MT1 mounted collet cuck will be too flexible to be of any use? And that a faceplate mounted one would be better? I don't have the experience to know this for myself, so if that really is the case, I will have to find a different solution. But then I ask myself, why would anyone sell MT1 collet chucks if they don't work satisfactorily?

Rowan

Thank you for those suggestions. I had not investigated ER collets, but will do so now. It seems to me that a Morse Taper collet chuck would work better than a faceplate mounting one, since it won't need to be centred. It looks as if an ER32 chuck would be most flexible since it seems to fit the largest range of collets, but I will see what gives me the amount of extension that I need in order to mill the parts that I'm working on.

I need to extend the shaft on my lathe. The shaft has an MT1 taper. I need to hold a milling tool in an MT1 collet, but if I just fit the collect into the end of the lathe shaft, it can't reach the work (the lathe has a gap bed, so the work can't be moved closer to the headstock). I can find MT1 to MT1 extensions, but I need one which has a through hole of at least 6mm dia for the M6 draw bar to tighten the collect. Does such a thing exist? From whom?

Thank you - Rowan

Yes, good idea, I will consider this if I can't find the rectangular tube that I'm looking for.

Thank you - Rowan