American Machine Radial Drill (ole timer) Refurb!

[Mr Ron]

I think plan A would be the easiest and quickest way with holes drilled for the studs.

[Wanna-Be]

I think plan A would be the easiest and quickest way with holes drilled for the studs.

Yah! very temped to go that route. But a lot of holes to tap and I want to go at least 5/8. I wonder if one of the tapping heads would handle taps that large??

Steve

[JackF]

Steve, call Mike Bray, "Cast Iron Mike", at Cast Iron Specialiats in Marysville. 360-657-7660. He could maybe give you direction to repair it yourself or have him do it.

Jack.

[scmods]

Steve,

I agree with you on the concept of the "bondo bucket" analogy applied to this machine. I guess it depends on whether the focus is on the machine or the hole it produces.

The MG-240 product I referenced in my previous post is a gas weld product that I use to reconstruct clutch jaws, gear teeth, and general build up on cast iron substrates. I have not had any difficulties with obvious color differences (like nickel electric rod) or hard spots. I try to preheat to orange-yellow, and the product is applied under a flux crust. The pre-heat to this level makes the application more responsive to torch manipulation without losing the fluidity in the working pool. The appearance of the working pool is sort of a "blob", kind of a 50's sci-fi, that responds to pushing the rod in and out by swelling or collapsing the "blob". Once you've established the root, the rod is pushed in to swell the working edge, the torch is then moved to the rod end of the blob, allowing the working edge to freeze while feeding the blob with more material. This is akin to withdrawing the rod, the blob collapses in the direction of travel as the base material heats up. The torch is then shifted back to the working edge, but back away from the ridge left from the now frozen bulge. The rod is then pushed in to create a new bulge, and the process is repeated. It works good, but employing it on a piece this big is the rub, at least on a less than industrial scale. The pre-heat necessary to avoid distortion and maintain workability of the weld site has to be general, rather than spot, and has to come up fairly slow to avoid cracking. Perhaps charcoal in a purpose-made brick box would be up to the job. The top surface could be covered with a layer of brick to reduce radiation and allow you to remain close enough to work long enough to get the job done. The work could be exposed by sliding the bricks around progressively.

One thing, you'd know the value of your project and whether or not repair was a good option rather than recasting. If it was me, I'd probably do it just for the experience good or bad.

OR, I might just drill holes.

Have fun!

Bill Walck

[Harold_V]

If I clean up and true up the holes with end mills and insert cast iron plugs, will that eliminate the resurfacing problems??

Yes. In fact, if your replacement material is similar to the original casting, with just a little luck you can install plugs that will be difficult to see, although the difference in oil saturation will most likely reveal them quite nicely. Machining the surface will not be a problem, assuming you create the proper press fits. The resulting surface will be quite uniform, and much more desirable than all the holes I see now. Problem is, you may have to install plugs over plugs, but there's nothing wrong with doing that, either. For a first class job, you may have to bore each hole. Using an end mill can yield its own problems, , the result of the end mill winging and chattering. Better than a drill, but not as good as boring.

I'd suggest you avoid any threading----it is impossible to hide such plugs, as the cast iron is brittle and will chip away where thin, so you'll see the starts of the threads, and that can extend a reasonable distance around each plug.

I understand your problem with swinging the casting for machining. You may also discover that the cost of a new casting is prohibitive.

Harold

[Inspector]

I'm curious. If the top is freeze plugged in so many locations won't there be such an accumulation of pressure that the top would bow even after machining? Or are you gents thinking of having the plugs go right through the table at each plug?

Pete

[Wanna-Be]

I am thinking seriously of doing this by insert/plugging these holes and do have some reservations about the freeze/expansion method. As I have been advised, cast iron has low thermal expansion properties. I think I could achieve a tightness by using ordinary interference fit method. But the question I would have; what is the correct interference clearance for cast iron? I'm not going to pressing these plugs in with an arbor press, most likely just what I can achieve in the mill under the spindle (to avoid removing the table from the setup after each hole). I'm also considering using some form of Lock-Tite to bed these pugs but if I have zero or interference, this substance wouldn't have way to squeeze out as I press them in.

I thank the Inspector for his valid point. And to answer one of his question; only about a 6 of these are presently drilled through the table top. Some more may be close enough that I may go all the way though in the repair. I looks like the nominal web thickness is about 3/4", getting thicker closer to the tee slot, hub and rim area.

Steve

[Wanna-Be]

I have been reconsidering which machine to do this work in. The 3" horz. boring mill is still "under repair" (low on priority list!), the K&T No.2 univ. horz. mill is the next heaviest and can easily handle this 400# table and another 150# of vee blocks and hold down stuff, etc.. But I believe I can better position and hold the table under the spindle of my Jet vertical mill, using the same vee blocks, on their sides, to clamp the table hub shaft while stabilizing the rim with table jacks and hold down hardware. I would be limited in the "Y" axis due to the table wide but could still work areas over the table "X" axis. If I run into "Y" limits, while still working over the table, I can always shift the ram over the column. Basically I need to see if I can get 14" clearance from the table and the column to do it this way. (may objective being to prevent machining forces toward the outer rim area with excess force on the table gibbs.

Now, question would be; How much weight of work and tooling can the Jet mill table handle?? I don't think I have seen this in their manual. (model JTM 1048 VS))

Steve

[JackF]

Steve, have you talked to Cast Iron Mike yet? Re using plugs, to allow the loctite to escape the blind holes you could drill a very small hole through the bottom as an escape route.

Jack.

[Wanna-Be]

Steve, have you talked to Cast Iron Mike yet? Re using plugs, to allow the loctite to escape the blind holes you could drill a very small hole through the bottom as an escape route. Jack.

Yes, we had a long talk about this yesterday. He did give me some tips but in the end, it think this method will be beyond my abilities and the cost to have him do it would be beyond my means. Nice guy, just a little older than me and still going strong and it didn't sound like he has plenty of work already.

Yes, I was think of the vent hole myself. Thanks. I have used Litharg and Glycerin (sorry, not sure of spelling) before but not for bonding, more for sealing threads on gas line fittings.

Thanks,
Steve

[GlennW]

You should have plug installation down to a real science after completing that little project!

You'll have plugs plugging the plugs that plug the plugs.

[Wanna-Be]

You should have plug installation down to a real science after completing that little project!

You'll have plugs plugging the plugs that plug the plugs.

It kinda, already is, as I contemplate the sequence. The bigger ones first, then the little ones that will be around the edges, thus, in effect "stacking" the larger.

I have some cast iron on hand but it is in 4.5"X4.5" bar stock. Plus I have a 800# cast iron knee from an old shaper that we scrapped out a few years ago. It is several inches think in some places and I plan to get it under a drill press and different size hole saws and produce billets (fill the pilot hole with 1/4" cast iron rod).

I have searched out a few potential suppliers and the prices are fairly reasonable until you get over 1 1/2" X 12". Then we are talking over $100.
Speedy Metal Mart in Wisconsin/Illinois is one but I'm going to check with a local metal supply that should have some to offer without any freight. I know Grainger has it but they have been closing the local stores and Seattle is the closest (150 mi. each way).

Steve