Member postings for Rowan Sylvester-Bradley

Well, I was proposing to glue it together using solvent cement, so that requires plastic. I'm not competent and I don't have the equipment to weld aluminium. I suppose I couild glue it together with araldite, but I don't think that would be as strong as solvent cement. Is there a better way to neatly join white finish aluminium tube?

Thank you - Rowan

That was a good suggestion, but despite fairly thorough searching, I still haven't been abkle to find what I am looking for. So still looking, and would still welcome any suggestions.

Thank you - Rowan

Form their web site the largest rectangular size they have is 23 x 11.5mm, which is too small for me. They supply larger square sizes, which I may have to go to if I can't find rectangular, but their mimimum order qty is £24 which is more than I was hoping to spend.

Thanks - Rowan

No, I don't think it would. I think the opening side would make the finished contruction much weaker. I suppose I could just glue the lid shut. But in most cases that I have seen the trunking is not truly rectangular, so it wouold be much more difficult to cut and glue accurately. I think I've got to find just plain rectangular tubing.

Thanks - Rowan

They only seem to supply these massive quantities, which is not cost effective for me (I only need about 2m of tube).

Thanks - Rowan

I suppose I could try this, but it would make the job much more complex than it needs to be if I could find the right size tube.

Thanks - Rowan

TP Extrusions seem only to make tube to order, which means they have massive minimum order quantities.

Sinclair and Rush only make small tube, max size 23 x 11.5mm This is not large enough for what I need.

Any other ideas?

Thank you - Rowan

Yes, I recognise that the end caps that I have seen may be intended for metal tube.

Rowan

I need some rectangular PVC white tube, say 20 x 40mm, or 25 x 50mm for a construction project I'm working on. I can't find anyone in UK who can supply this, But surely this must be available? I can find end caps for it, which surely means that the tube must exist? Can anyone suggest where I might get this?

Thank you - Rowan

I take your point about no chart can be accurate, but if I don't have the experience (or if I'm training my grandchildren to use the lathe, who certainly don't have it), I have to start somewhere...

I braved the cold and counted the teeth. The large gears both have 65 teeth, and the small ones 25 teeth. This means (if I've got this right) that the ratio is (13/5)^2, or about 7:1 (more precisely 6.76:1).

This means that the speeds of the main shaft (in rpm) are:

Backgear Without With
Pulley 1 526 78
Pulley 2 292 43
Pulley 3 156 28

Now I can get on and make my wall chart!

Thank you - Rowan

All those are good suggestions thank you, but I think I will count the teeth. I am creating a wall chart showing what settings (i.e. which pulley and whether backgear or not) to use for various materials and various diameters, and I'd like the chart to be as correct as possible. I do have a tachometer, but I haven't yet made it work reliably, so measuring rpm is not as straightforward as it should be...

Thank you - Rowan

Edited By Rowan Sylvester-Bradley on 09/12/2022 13:07:55

Edited By Rowan Sylvester-Bradley on 09/12/2022 13:08:30

Does anyone know the raito of the backgear on a Portass PD5 lathe? I know that I can count the teeth on the gears, but the lathe is out in the garage, and it's cold out there! And counting the teeth would be a pretty tedious process... So if someone knows the answer I'd be very grateful. If they don't, then gear tooth counting is coming up in the coming days, and I will report the results here...

Thank you - Rowan

How do I release the tailstock MT1 chuck or centre from my Portass PD5 lathe?

Thank you - Rowan

What exactly is the problem if the tool post is too big for the lathe? What fouls with what?

Can one buy toolposts of this type smaller than the 250 size? From whom?

Thank you - Rowan

Thank you for those answers. In trying to understand whether this will fit, I need to understand the function of the piece of metal ringed in red here:

What is the function of this? Can I remove it? Will the toolpost still work? Or can I make a smaller version of it, that will allow tool holders to be slid down so that they extend below the dovetail on the toolpost?

Thank you - Rowan

Does anyone know whether the wedge gib type cuneiform quick change toolpost 250-000 will work well on my Portass PD5 (3.5 inch swing) lathe?  What will be the pros and cons of this? Is it too big? Can you recommend anything better?

Thank you - Rowan

Edited By JasonB on 14/11/2022 16:39:46

According to Google many suppliers use the term "bar" to mean a flat fairly narrow strip. Anyway, that's what I meant.

Thanks - Rowan

The process that Martin suggested is almost exactly what I was thinking of (except that I was going to use steel rod rather than brass - I'm not too concerned about marking the shaft).

Thanks - Rowan

Thank you for all that hepful advice. It sounds like the "treppanning" process is not going to work, or is going to prove troublesome and difficult. Although I see that you can buy special "face grooving" tools for this (e.g. https://www.sandvik.coromant.com/en-gb/products/pages/face-grooving-tools.aspx). Does anyone have any epxerience using these?

So my process now (based closely on JasonB's suggestions) is:
1. Cut the stainles steel rectangle to a rough circle using a hacksaw. Whether this just means cutting off the 4 corners, or doing more cutting probably depends on whether I can reassemble and get working my power hacksaw.
2. Grip it in the 4-jaw chuck, and cut the outer 6mm to 76mm dia using an HSS tool.
3. Reverse it in the chuck (maybe change to the 3-jaw) and cut the other 6mm to 76mm dia.
4. Still holding it in the chuck, drill and bore the 25mm hole.
5. Hold by the hole in the three jaw chuck with the internal jaws and turn the outside circumference to 75mm dia.
5. Face both sides and the circumference.
6. Drill and tap the radial hole. I understand that I can't tap 25mm deep. I was thinking of just tapping it as deep as I could, and then "extending" the grub screw with a rod say 4mm dia ground to a conical point. This can just be loose inside the hole.
7. Finish with emery or similar. Make a 25mm arbour if necessary to protect my fingers

Other issues. If 304 is not the best grade to use, what is best? Yes, it does need to be stainless.
Yes, what I have is an 80mm long piece of 12mm x 75mm bar. I know that facing it will end up with it less than 12mm thick. I was just going to take off enough to get a flat surface. The eventual thickness is not very critical.

Thank you - Rowan