# Cutting portafilter (to make bottomless)



## Deidre (Aug 13, 2019)

I have an extra spouted Londinium 1 portafilter that I'd like to convert to a bottomless pf. Will this drill bit do the trick?

*
Diamond Coated Glass Hole Saw Drill Bits for Ceramic Tile Marble Rock Porcelain
*


----------



## El carajillo (Mar 16, 2013)

NO You need one for metal, do you have a machine to hold it in ? (drill press). Check dimension of P/F 60 mm would be closer.


----------



## Inspector (Feb 23, 2017)

Previously i have converted sage 54mm to bottomless. It wasn't brass it was stainless steel. Was a long process cant remember now if i used 51 or 57mm bosch progressor hss attached to pillar drill. I dont think a hand drill would be good for this job.


----------



## Deidre (Aug 13, 2019)

Thanks @El carrajillo and @Inspector.

I also have an official L1 bottomless pf, but wanted a second one. ☺

Is it solid brass then, under the shiny steel coating?

The cut-out on the manufactured bottomless L1 pf measures a hint under 50mm across the opening. Your mention of 60mm raises another question: Am I measuring the wrong area to get the correct size?

So, this sounds not as straight-forward as I thought... not a 15 minute job, then??


----------



## ajohn (Sep 23, 2017)

If I was doing I'd use an HSS hole saw a bit smaller than the portafilters basket size and finish with a file or maybe a burr in a dremel but if it's stainless that would probably blunt pretty quickly.

The problem with doing it is that the hole saw may jam. This means that the portafilter needs firmly locating so it can't spin or move and having a jam when a hand drill is used wont be much fun. When a hand drill is used it is likely to jam so it would need to be firmly kept in place even if the jam stalled the motor in it. Some would just let go - not a good idea and a jam like that might wreck the drill.

If a pillar drill is used the portafilter need to be firmly held to the table and positioned so that it gets drilled in the correct place. How depends on what people have around. I want to do one so will probably use a drill vice bolted to the table plus a bolt through the table positioned at the end of the handle to prevent rotation or a block of wood bolted in position to achieve the same thing etc. It will try and rotate clockwise when the hole is cut. The drill vice just needs to keep it in position. Obviously this sort of thing needs some thought when it's done and either the portafilter or drill vice may not be suitable for this method but the main thing is to think about the rotational forces when things are being cut like this or even when holes are drilled.

If anyone ever buys a pillar drill for home use it's best to look for one that has a table that can be rotated and also swung around the column as these can drill where ever something is clamped. Sadly they are thin on the ground and may not even exist any more.

John

-


----------



## El carajillo (Mar 16, 2013)

Deidre said:


> Thanks @El carrajillo and @Inspector.
> 
> I also have an official L1 bottomless pf, but wanted a second one. ☺
> 
> ...


 You would only need to bore it out to the larger size IF you were going to use a deep basket which would not fit in the recess.

As you would not be using a deep basket on the L1 the 50 mm would be OK.

You would need some means of holding the P/F still and central to the pillar drill or you would end up with an off centre cutout and a lot of tidying up to make it neat.


----------



## Deidre (Aug 13, 2019)

I have access to a vice and tools (and a competent side-kick ?). I will heed your advice & instructions most carefully. Thank you @ajohn & @El carajillo


----------



## ajohn (Sep 23, 2017)

Off topic but the right style of pillar drill is around again. Probably the cheapest

https://www.uktoolbox.com/products/sealey-tools-pillar-drill-bench-12-speed-840mm-height-370w230v.html?F1=0&ID=510344&utm_source=GoogleBase&utm_media=Product+Search&gclid=EAIaIQobChMInvewkpvq5gIVia3tCh1l1w4wEAQYGSABEgJU6fD_BwE

Axminster may have done the same with an oblong table but no good at all if that prevents full table rotation. Probably more industrial. The above looks to be the same as I have. Not used all that often but always for jobs it was never intended for - metal.  It's probably 25 years old now. It is not the most solid of machines but can do if that is remembered. A true industrial one would be many times heavier even in respect to the axminster. I haven't done a portafilter on it.

John

-


----------



## ajohn (Sep 23, 2017)

Deidre said:


> I have access to a vice and tools (and a competent side-kick ?). I will heed your advice & instructions most carefully. Thank you @ajohn & @El carajillo


 That's not really possible. I couldn't add any more than I already have. It needs locating and additional steps to prevent rotation. That's the problem one. The other cutting force is downwards. I think that joey made a jig when he was doing them. Another but more long winded option. It would still need clamping to the table. I would go in other directions as I was trained initially as a toolmaker  that doesn't always mean I would go in the correct one for others. In this case though proving people realise what I am suggesting all should be ok. It's not rocket science more just identifying the problems.

John

-


----------



## Deidre (Aug 13, 2019)

ajohn said:


> That's not really possible. I couldn't add any more than I already have.
> 
> John
> 
> -


 Just to clarify... I am very much A-OK with all instructions and advice given earlier. (I think you thought I had made a typo, perhaps? It was indeed "*h*eed" not "need". (Or, did I misunderstand your first sentence?) Thanks☺


----------



## Inspector (Feb 23, 2017)

https://www.coffeeforums.co.uk/topic/41873-grinding-out-a-portafilter/?tab=comments&do=embed&comment=600270&embedComment=600270&embedDo=findComment#comment-600270

i have found this old topic


----------



## joey24dirt (Jan 28, 2017)

Just to add....when doing portafilter conversions, whatever the material, just go slow and steady. When I convert the sage stuff I stick to 80-90rpm. It's 5mm thick stainless so it takes a while. Plated brass is waaay easier 

Sent from my iPhone using Tapatalk


----------

