Conti Prestina Espresso Machine Restoration 101 (Completed and Indexed) - Page 33

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
jedovaty
Posts: 536
Joined: 13 years ago

#321: Post by jedovaty »

Dr. G - you must know a secret on how to get that spring out with it in an uncompressed form?
:P
Replacing spring in commercial lever group

User avatar
drgary (original poster)
Team HB
Posts: 14347
Joined: 14 years ago

#322: Post by drgary (original poster) »

That's why I've got that spring clamp! :D

I'll be fitting it with angle irons soon, aka punched crown bolts.

That's a good reminder that the spring can be tied up in compressed position before releasing the tension to clean the piston assembly. I've got the ties too.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

jmc
Posts: 160
Joined: 16 years ago

#323: Post by jmc »

To lessen stresses on the wood you need to have the holes for the threaded rods in as close to the part you are compressing. I would suggest redrilling them closer in so you have just enough clearance around the circular boss that the lever mechanism is on to compress the spring.

John
John

User avatar
drgary (original poster)
Team HB
Posts: 14347
Joined: 14 years ago

#324: Post by drgary (original poster) »

Yes. That thought crossed my mind last night. I will definitely do that. Learning by trial and error.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

User avatar
drgary (original poster)
Team HB
Posts: 14347
Joined: 14 years ago

#325: Post by drgary (original poster) »

My contractor happens to be here today. He's an expert carpenter. I showed him my clamp with its wood split almost entirely through. He suggests rather than brace the existing plate I should cut new end plates out of 1 1/2 inch plywood, which won't split. The challenge is finding such plywood without buying a whole sheet. Apparently it's used for subfloors where the beams are wide apart. He says an alternative is to use thinner plywood and cut identical holes and screw that facing against the end plate. He also has the right-sized drill bit to cut a clean hole in one of the plates for the piston end. Since he's coming back soon, I just may have him do what will take him 15 minutes. :mrgreen:
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

jonny
Posts: 953
Joined: 13 years ago

#326: Post by jonny »

I'll add my idea, which is a culmination of what has been suggested:
Go to Home Depot or comparable.
Buy 2'x4'x1/2" hardwood plywood (used for cabinets and furniture)
Cut 3 12"x12" pieces and 6 12"x6" pieces.
Glue three 12"x12" pieces together and use the hole saw to cut the recess for the piston. If the hole saw isn't deep enough, cut each plate before glueing.
To make the square recess in the top easier to cut, you can cut your plates in half through the center where the square hole needs to be cut. Alternate this seam with the three plates so none of the seams are in line. (do the top one offset from center, do the middle one perpendicular, and do the bottom one offset in the opposite direction as the top). This allows you to not have to cut a square hole and none of the seams will overlap. Or just glue 'em together and cut it the way you did before.
Once glued together, it should be solid. Your plates will end up 1.5" thick.
Like mentioned, put the bolts as close in as possible since the distance from the reaction will multiply the stress in the plate.

I have zero experience with this, so I have no idea if this would actually work, but since you know how the lumber reacted in your first attempt, you could probably make a guess for how something like this would fare.

User avatar
drgary (original poster)
Team HB
Posts: 14347
Joined: 14 years ago

#327: Post by drgary (original poster) »

Jonny,

Simpler's better here. FYI I discovered a hole saw that works with metal is useless for wood. It just drifts all over the surface. I'll redo the plates in thick plywood.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

jedovaty
Posts: 536
Joined: 13 years ago

#328: Post by jedovaty »

I'm having one of those "Oh S..t" moments. I have to work with wood? :shock:

User avatar
drgary (original poster)
Team HB
Posts: 14347
Joined: 14 years ago

#329: Post by drgary (original poster) »

I'll lend you mine when I've got it reworked.
Gary
LMWDP#308

What I WOULD do for a good cup of coffee!

User avatar
DJR
Posts: 486
Joined: 14 years ago

#330: Post by DJR »

I've tried lots of products and they are all faster than molasses, but not better. One or two days doesn't do the trick. But a week - ten days will definitely replaced the rust with a gray powder that can be washed off. Molasses doesn't seem to etch the metal and is non-toxic and if it entered pores in the metal and didn't get completely removed would be pretty harmless. It just doesn't work over night.

Gary, if you want to make the end plates out of plate steel, I could do that for you.