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Hard Chroming cast iron

stan martin

Aluminum
Joined
Dec 26, 2005
Location
calif
Has anyone had any experience hard chroming cast iron? I have two cam lifter blocks each one has four holes, they are not round. The lifters have worn the holes, and I would like to take some wear out of the holes. Will hard chroming work here? will it plate into the lifter holes? These two blocks are a cast part, and not available anymore. They are for my 36 indian four motorcycle. Any thoughts? stan
 
Making hard chrome plate into a bore is tricky, and i believe will require tooling to make it work well. Think you would be better advised to overbore the carrier and hard chrome the OD of the tappets. They are most likely not round or parallel if the carrier is worn, so putting them into a good hole would present trouble without some corrective work.
Cheers Ross
 
Boring the holes would be a good idea, but they are half round. If you would take a dime, and cut 3/16 off of each side would be what the holes look like. Hard chroming the lifter may be a better option. Stan
 
Ditto previous suggestions to bush the bores. Race engines routinely have bronze lifter bore bushings installed. Any well-equipped automotive machine shop should be able to handle the job.

Roger
 
Just an idea, but how many holes need this? Do you have enough there to bush it up and then broach out the shape? If you don't have too many holes, I would think you can make a drill rod broach that would last long enough to do the job.
 
hard chroming anything can be a big PITA
It never seems to come out evenly and is somewhat of a problem for the plater to get just the amount you need. If the holes are out of round now, the chrome will pretty much follow the contour; so, if you've got a lot of dimension to make up, it'll take a lot of chroming.

and....

the chrome tends to "tree up"--- in other words, the chrome will get thick(er) where there's a sharp corner; either external or internal. Both present problems in that you'd have to then machine/grind the chrome..not an easy task.

Hard chrome (industrial) can be ground with a lot of patience, and the right wheel composition.

I'd follow others' advice and bush them using some form of positive retention, but replaceable if needed. If they're a "D" shaped hole, you could have the bushing(s) wire-EDM'd to any dimension you want.
 
Chrome

From what I understand, hard chrome is just "thick" chrome, nothing special about it. Then a typical part, say a chrome bumper is just nickel plating with a layer of chrome to prevent oxidation of the nickel.

And I believe cast iron is not as easy to plate as mild steel; while a good plating job would call for a substrate of copper.

So if you choose to plate, and are not expecting to get high-miles out of your Indian, why not try plating copper? From the sounds of the comments above, the results from the plating shop could be fitted a lot easier than chrome.

Dan
 
What do the lifters look like?

Bore the lifter bores round and back on location, and either make new lifters or plate and grind the OD of them to fit.
 
I think that if you decide to plate you should do as DJ2 suggests and get copper plating true it up and then get a layer of crome or nickel plated on top a tenth or so thick. Years ago I worked for a place that did on site brush electroplating to repair printing press cylinders. We would build up with either copper or silver, Then file and stone the repair flush with the rest of the cylinder and then we would put on a layer of nickel or cobalt about 1 or 2 tenths thick. These were repairs to hard chromed clyinders and they seemed to stand up the company I was working for travelled all over North America doing these repairs.
 
Hard chrome (industrial) can be ground with a lot of patience, and the right wheel composition.

.

I haven't found hard chrome all that difficult to grind, using the same aluminum oxide wheel as for hardened steel. Granted, there's better wheels out there if you're doing a lot of it, but for the occasional chromed bore or od, I use the regular wheel, just dress it a bit more often; also, it's slower going than steel, but for the occasional piece, not a problem.

I don't think the hard chrome process uses a copper preplate; baking the chrome may improve adhesion-the chromer should know.
Re brush chrome/nickel, adhesion was usually an issue.
Remember that chamfers and grooves/undercuts and holes will need to be ground in as well; things can be masked but it was always a PITA. YMMV
 
Don't make an easy fix difficult or expensive by fooling with hard chroming.

Have the lifters ground round.

Bush the lifter block bores with bronze.

Ream the bores to fit the lifters.

thnx, jack vines
 
Have the lifters ground round.
...
Ream the bores to fit the lifters.


I know it's an old thread. I ran across it looking for info on plating cast pieces to restore wear on old bed ways.

Anyway ... I don't think the OP had the option of grinding the lifters round. The lifters have a cylindrical roller bearing that rides the cam lobe, and the keyed lifter shape keeps the roller aligned with the cam. Machining away the indexing shape would accelerate wear or destroy the lifter.
 
I have done a certain amount of hard chroming and know people in the business. First, hard chrome is deposited straight on the steel. You don't want a soft material under it. The typical solution is 33 oz/gallon chromium trioxide and .33 oz/gal sulfuric acid, no brighteners. You normally want more than a thousandth of chromium to make it hard and usually build up more, then grind. Grinding is not a problem. The plating solution has a fairly high resistance, partly because of polarized layers formed by the current. The result is that high points stick up through the layer and get more current. The first plating repeats the finish on the iron but it soon goes into a matte surface like you see on measuring instruments. From there it goes into a dendritic buildup (dendrite means leaf) and it turns into a fuzzy mess that has to be ground off.

A local shop I do a lot of electrical work for has shafts built up and ground back to original size on a daily basis. They haven't been doing ways, but one of my last projects was upgrading a Mattison surface grinder with a 36" X 96" capacity. If that would handle the ways in question, I will talk to them.

Bill
 
They are for my 36 indian four motorcycle. Any thoughts? stan

Low-stress motor. Unless his G'dad was Burt Munro.

Flatted both sides, bound to have wear that has altered their shape as well, and not the same top to bottom?

One could retain the flatted sides. How about Bronze plating them 'too thickly', then making a broach and pilot rig to bring them back to OEM shape, location, and size?

Bill
 
Burt had a V twin.

Bill

More than one, even had it appeared to be the same one, way he kept making and replacing parts...

Old neighbors in PA had a pair of Indian Chiefs. His and hers deal. Another had a side-shift Harley, and next door a Triumph Bonneville that even actually ran about twice a month.

All seemed pretty ordinary, mid 1950's into early '60's.
 








 
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