How To Make Your Own Naked Portafilter

[cannonfodder]

I enjoy do-it-yourself projects, so I decided to cut a bottomless portafilter for my Faema. When I got the machine there was an old, nasty, beat up portafilter in the parts pile. Once I finished rebuilding the machine, I ordered a proper portafilter and basket. Problem here is that I have become accustom to using the bottomless portafilter as a learning tool. That tool is especially helpful when dialing in a new machine. So I decided to chop the bottom off of this old reached PF.

I wrenched off the old busted handle and soak the PF head in some Joe-Glo to clean it up and then off to the garage for a lobotomy. The first step is to mount the head on a secure working platform. You do not want this to wiggle around while you are cutting on it.

There are several ways you can go about chopping the bottom off a PF, but what I find easiest is to drill around the bottom of the PF. This easily removes excess material and makes sure you do not cut to close to the inner edge. As you can see from the photo, I ended up using a rubber-padded clamp to securely hold the PF to my work surface.

Next, I put a tungsten carbide cutter in my rotary tool and commence to connect the dots. The closer you drilled your holes, the quicker you will be able to cut between them. Keep that in mind as you drill the base.


A word of caution. Using this type of cutter produces an incredibly fine shaving. Experience has taught me to wear gloves and long sleeves while doing this. Some eye protection would be a good idea as well. This fine metal 'hair' will float on the breeze created by your working tool. It gets on everything and without gloves; you will end up with dozens of these fine shavings stuck in your hands and arm.


Once the base is off, clean up the shavings and move to a ruff grinding stone. Round out the jagged edges but do not get to close to the inside wall of the PF.


Now switch to a medium or fine stone to remove the remaining excess material. This is where you want to make the final shaping of the hole and make it nice and symmetrical.


You could stop here but I like to go one further. I use a polishing stone to remove the mill marks left by the fine grinding stone. This polishes the inside edge and gives it a professional appearance. This is also when you want to remove any burrs around the outer edge. You do not want a sharp base, it will cut your table to pieces when you tamp on it.


Now you have turned that spare old portafilter into working piece of equipment that should provide you with years of service. Just remember to take your time. You can always grind a little more, but you can never put back. Total start to finish, about one and a half hours.

[HB]

Excellent work Dave! Thanks for taking the time to photograph and write your how-to. I've linked this thread to the end of Perfecting the Naked Extraction as an aid to those who want to try bottomless portafilters on a shoestring budget.

[s_m_k]

Nice smooth finish.

I used the same technique with an aluminum (yeah, I know) portafilter. If only I could use a grinding wheel on aluminum. I settled for hand filing and drum sanding with a battery-powered Dremel tool. I still haven't finished it to my satisfaction, but I had to start pulling bottomless shots to satisfy my curiosity.

[cannonfodder]

Now this is why I like a bottomless PF. Without it you could not revel in my humiliation. Unlike Jon's perfect naked triple, here is Daves' perfect, what not to do, naked double.



Houston, We have a Problem...







The puck looks good, no obvious channeling.


Now in my defense, these are using my new LM double basket, which appears to be part of my problem.


I need to call EPNW tomorrow morning. My 58mm tamper sticks in my 58mm basket. I have to hold the PF down and wiggle out the tamper, which I am sure, is adding to the above blown shots.

[barry]

a hole saw is so much faster and neater.


--barry "loud, though"

[lino]

Huh?

I thought those HB tampers solved all extraction problems...
Has Dan been over selling them? <smirk>




ciao

lino

[cannonfodder]

I had thought about a hole saw, but I don't have one. This is what I had in the garage. If i ever cut another I will pick one up to try.

I brought my LM basket to work with me so I could try my generic 58mm tamp. It fits that one. I wonder if the basket is slightly under sized or my HB base is a hair too large. It fits my Isomac baskets just fine.

Normally, I can pull a pretty darn good shot. Having to wiggle the tamper out of the basket has to be disrupting the packing, or at least that is the excuse I am going to use for now.

[shadowfax]

last year I just took my Gaggia's PF to a local machine shop and they lathed it out (very well) into a naked PF for about $15, and 2 days' wait... How much is your time worth?

Looks cool, though, I don't think I could get one looking that nice with a dremel!

[cannonfodder]

There are lots of other options. EPNW will also cut one of your existing PF's. I am a do it yourself guy and enjoy tinkering so I enjoyed cutting it. My time is free and I already have the tools. It just takes a little time and patience, and it beats sitting on the couch watching reruns.

[OlywaDave]

And you did a really nice job of it. I got a dremel and all the attachments... Hmmm I have to say it looks like so much fun that I'd think about doing this at home too.

The new factory bottomless PFs are pretty nice too. Lots of options with more to come I suppose.

[Fr. John]

I know this has been done before but thought I would show my results. I am surprised at how easy this was. I know brass is soft (I was a fine art metals major) but wasn't sure how clean a hole saw would cut. After my brother and I came up with this super complex jig for holding the work piece, it went like butter. Now I have to master using it.

I thought the pic taken right after the cutting was the most interesting.

I have to admit it was kind of fun and saved me $60+.

[cannonfodder]

Nice job. Next time I will have to invest in a hole saw.

I took a second look at your portafilter. It looks like the base is about half as thick as the one I cut. When I did my Isomac PF, I remember it taking less time and effort than that Faema I cut.

[Fr. John]

Nice job. Next time I will have to invest in a hole saw.

I took a second look at your portafilter. It looks like the base is about half as thick as the one I cut. When I did my Isomac PF, I remember it taking less time and effort than that Faema I cut.

Thank you.

I think it took about 5 minutes to make the cut. I really went slow and used a lot of cutting fluid. I'm still amazed how cleanly it cut, virtually no burr when done. A little work with a burnisher and some sand paper and it was perfect.

[pravspresso]

Metal is much easier then i expected to work with.

Middle stage now..

Going to take 3hrs tomorrow perfect it.

[Fr. John]

Too bad you didn't use a hole saw, you'd have been done in 10 minutes. 3 hours sounds like am awful long time.

Good luck though.

[pravspresso]

Yeah..i would have..but i didn't scroll down this blog.

I just saw the first set of pics.

Otherwise..this portion took me about 10min.

I picked up a dremel all carbide bristle type brush attachment.

Tested it out on one area...cut it like butter in 30 seconds.

I'm guess-timating a solid hour to finish this up.

[pravspresso]

Polish it up later..

the first shot was much smoother and had a more rounded out taste (softer).

[barry]

just an fyi: if you dress up the center disk so there are no sharp edges or such nastiness, they make really good doo-dads for rugrats to play with. if you have two, they are great tiny cymbals with excellent tone.

[arossphoto]

I think it took about 5 minutes to make the cut. I really went slow and used a lot of cutting fluid. I'm still amazed how cleanly it cut, virtually no burr when done. A little work with a burnisher and some sand paper and it was perfect.

What size hole-saw did you use? I was looking at some at the hardware store today and some had a mandrel (a bit in the center to guide the saw) and some did not. My first thought was the mandrel would be important to keep the saw centered, but then I wondered if it would get in the way as the saw went deeper. Did you use a drill press or just hand-held?

Cheers,

Andrew

[Fr. John]

The size of hole saw will depend on your PF. Mine was perfect at 2 ¼" w/ a mandrel. I wouldn't want to do it without the center bit. To guide the center bit (which is only useful until this hole saw bites then it's purely superfluous) I plugged the PF hole with a tapered dowel rod (tapered like a cork so it got tighter with pressure). That gave the centering bit something to bite into and stay centered.