File or use a Dremel,,?

[Stevekane]

Hi, I got a couple of thin stainless pipe cover/finishers that I need to open out by around 3mm dia, and Im trying to think of a way of doing this to give a neat finish, I have a Dremel and some cheap stones, any thoughts on whether this would work or any other ideas appreciated. Ive attached a photo of a slightly larger finisher for ref.
Steve

 

[--Tom--]

Can’t see the photo, but from description a step drill might do what you want as is useful to open out holes in thin materials

 

[Amplidyne]

Trouble is with stainless is it's hard to work. However you do it is going to be a pain. As suggested a step drill or cone drill might be worth a go. Clamp the work down well whatever you do. You could also try a rotary file of burr in the dremel, or a grinding wheel. I should think hand filing through a hole like that will be a right b.

 

[Stevekane]

Ah, my fault, I was so keen on getting the post up I forgot the photo! Hopefully its here now,,,,its very thin material and Im worried about a step drill grabbing,,,but the people Im buying from have sent a pair which are the wrong size anyway, more are in the post so and if they dont ask for them back I might have a couple to practice on, I have to ease the holes to sit neatly around the shoulder on a 15mm compression nut and I like the control the Dremel might give me if it works,,

 

[ChaiLatte]

A sanding drum on the Dremel might be as good as a stone. It would do for final finishing.

To me, setting the Dremel up like a router table and moving the part over the 'cutter' might give more control.

Similarly, if you had a drill press and sanding drum, that might give good control as the stainless part can sit on the drill press table.

Will you draw a circle on them to give a line to sand to?

 

[Stevekane]

Yes, I thought I would scribe a line on the inside to work to, and I like the idea of fixing the dremmel, that might be reasonably easy to do,,and then try different cutters/ sanders, great idea for giving me more control I think.
I dont have a Step Drill but in any case I think there would be a good chance of it grabbing,,,but I could mount the nose of the dremel up through a hole in some thin ply and steady the rear end,,I can visulise that working,,many thanks and I will let you know how I get on.
Steve.

 

[woodieallen]

Let's rewind. Those look like very thin cheap Chinese plastic two-a-penny and cost SFA. So what diameter pipe are you wanting to fit them round ? 22mm probably.....15mm - 2 x 3mm

Why not get the proper stuff ? Something like this ?

https://www.toolstation.com/talon-p...&utm_campaign=googleshoppingfeed&gad_source=1

None of the orher suggestions are going to work on that thin stuff. They will deflect under pressure

 

[ChaiLatte]

Let's rewind.

The items are stainless steel, not plastic (see later photo). The hole needs enlarging to fit around a compression fitting, so no standard part will be available to achieve this.

---

Not for here, but more generally, a step drill could work if the metal item was supported on (even sandwiched between) plywood that has a hole drilled in it the finished size of the required hole in the item. The hurdle in this case is that the exit of the drill would be the top of the cover, so it would not work.

Again, because of the conical shape, there is no easy way to drill from top down and simultaneously support the edge. Also step drills come in a finite number of diameters and Murphy can guarantee that the required size is halfway between two step drill increments.

 

[wurglesnash357]

If you decide to drill, be aware that stainless steel will work harden if you pussy-foot about with it, and that way lies madness. Once the drill bites, make it work hard and don't ease the pressure until you're through. Yes, that can cause problems with thin metal, so make sure that it's backed up with something substantial. Would plaster or body filler or something similar in the back of the cover/finisher provide enough support?

Les

 

[Stevekane]

Let's rewind. Those look like very thin cheap Chinese plastic two-a-penny and cost SFA. So what diameter pipe are you wanting to fit them round ? 22mm probably.....15mm - 2 x 3mm

Why not get the proper stuff ? Something like this ?

https://www.toolstation.com/talon-p...&utm_campaign=googleshoppingfeed&gad_source=1

None of the orher suggestions are going to work on that thin stuff. They will deflect under pressure

If only life were so simple,,but no they are stainless of the cheap chinese vareity and despite hours of trawling around the internet the ones Im getting are the closest to whats required, the toolstation ones are actually quite deep and there is insufivient room for them. Ive been thinking abount plywood backing too so many thanks for those suggestions too,,,more to follow,,
Steve.