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hal9000
06-08-2012, 03:26 PM
Last night I made a craigslist purchase of an old craftsman 12" lathe just so I could get some of the accessories. One of them was the factory milling attachment. After I got home and was making a close inspection of my haul, I noticed a slight bulge below each of the retaining pins indicating that sometime in the past the mill was forced against the pins and cracked the cast iron around the holes out....

Just curious how I should go about fixing this? Any ideas? My first thought is to just knock out the broken parts, weld, machine, and re-drill the holes, but my cast iron experience is limited to knowing that it can be tricky stuff....

Mtw fdu
06-08-2012, 03:36 PM
If you can post a pic of it we may be able to get a better idea of the problem.

Mtw fdu.

firbikrhd1
06-08-2012, 04:23 PM
Having no picture to help me fully understand the problem, I'll offer the following experience.

I obtained an Atlas MF Mill with vise. Upon cleaning up the vise i discovered that at some point the fixed jaw had bee broken off and repaired with brazing. So far this repair has worked well and not shown any signs of breaking again. With common sense use it will probably be fine for as long as I want the Mill.

So, that all said, perhaps brazing would be an acceptable repair for your issue.

hal9000
06-08-2012, 05:06 PM
Thanks for the responses. I'd considered brazing but since this is probably the point where all the leverage against the whole mill concentrates I was concerned it might not be strong enough.

I need to clean the attachment up so the damage will show up in a photo. I'll probably start on that tonight and see about posting pics tomorrow.

mf205i
06-08-2012, 10:30 PM
The pin and taper system isnít up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
Donít apply heat!
Good luck, Mike

flylo
06-08-2012, 10:55 PM
Mike,sounds like a great mod. Any chance of getting a picture of this mod. I think a lot of us will be doing this. Thanks! Eric


The pin and taper system isnít up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
Donít apply heat!
Good luck, Mike

CCWKen
06-08-2012, 11:18 PM
I'm not sure what "pin" you're talking about. The picture below shows the Atlas Milling Attachment. The only pins I know of are the beveled pins that fit against the swivel when you pull the compound off to mount the attachment.

http://img.photobucket.com/albums/0903/CCWKen/ToolBox/Craftsman%20Lathe/Accessories/MillingAttachment.jpg

davidh
06-09-2012, 11:04 AM
The pin and taper system isnít up to the task. Even with parts that are in perfect order you will see movement - oil pumping from this joint. Drill and tap a .375 ish thread in the cross slide stud and drill a corresponding clearance hole through the center of your attachment between the gussets. Relieve the high spots and bolt the attachment on with a SHCS or a bolt with spacer. A piece of thin paper, phone book page, between the parts will ensure that nothing slips without the need to gorilla tighten them. This modification yields such good results that it is worth doing to undamaged parts, so you might consider doing both of them while you are at it. Having a threaded hole in the stud makes it much easier to rigidly mount other fixtures.
One more point, this modification is also the cure if your lathe or the attachment has been used a lot as the attachment will want to return to the worn spots, from previous use, on the stud taper and this can make it very difficult to properly tram for your setup.
Donít apply heat!
Good luck, Mike
.
.
i too would like to see a pix. . .

radkins
06-09-2012, 12:10 PM
I'd considered brazing but I was concerned it might not be strong enough.


Don't underestimate the strength of a properly done braze joint, it most likely will be nearly as strong, or even AS strong, as the original cast iron. If you do decide to weld this thing brazing would probably be a much better way to do it than arc welding with Nickle rod.

Rex
06-10-2012, 11:58 AM
The stud he is referring to is the dovetailed boss sticking up from the cross-slide, to which the milling attachment or compound clamps. You drill and tap this for that bolt which goes vertically through a new hole in the milling attachment down into the threaded hole.
Great idea BTW.

hal9000
06-11-2012, 06:03 PM
Sorry for the delay in pictures guys.... busy weekend. I'll get them tonight hopefully.

CCWKen, I am indeed referring to the bevel pins that fit against the swivel. I was having a "duh" moment and couldn't come up with the correct description for them when I first posted.

I too would love to see photos of the completed mod that Mike described. Sounds like the path of least resistance in terms of repair. My only question would be how critical the centering of the drilled and tapped hole in the cross slide stud is? I'm assuming that it's a standard drill press operation right? Otherwise i could envision something like mounting the stud in the lathe jaws and drilling from the underside using the tailstock to get things perfectly centered....

Second choice at this point is to re-drill and tap new holes for the bevel pins in a different location (probably 3 pins, one dead center between the originals, and one each on the machined boss for the zero marks on the base of the attachment)

hal9000
06-11-2012, 07:11 PM
Here are a few shots. If you look carefully you can see the cracks. You can also see the bulge on the opposing pin (the one not in view) if you look very carefully.

http://i71.photobucket.com/albums/i149/Halle62/Lathes%20and%20such/mill3.jpg
http://i71.photobucket.com/albums/i149/Halle62/Lathes%20and%20such/mill4.jpg
http://i71.photobucket.com/albums/i149/Halle62/Lathes%20and%20such/mill5.jpg

+ or - Zero
06-11-2012, 07:41 PM
I'd just braze it, clean up the braze and threads, make sure it's still flat (and if not flatten it using best method you have, or take it to some one that can make it flat again) then use it.

But then I'm used to brazing cast, if you are not comfortable brazing it then I'd say go get someone that is good at it to do it. The part is well worth the repair, I use mine very often.

hal9000
06-12-2012, 12:50 PM
Do you mean flow braze into the cracks? Or break the casting completely or V the cracks out and braze?

Somebody also suggested silver solder as a better flowing alternative. I might experiment on some scrap since I have some 15% silvolux lying around.

+ or - Zero
06-13-2012, 12:58 PM
Do you mean flow braze into the cracks? Or break the casting completely or V the cracks out and braze?

Somebody also suggested silver solder as a better flowing alternative. I might experiment on some scrap since I have some 15% silvolux lying around.

Sorry for the delay in getting back to you I was out of town yesterday. I did mean braze, but I'd also have stablized the cracks first. But if you have the silver solder and it's high silver content (there are lots of silver --scratch that I just saw you said 15%.

So in light of that silver solder would no doubt be a better choice, but clean, clean, clean (and unless you are already comfortable soldering) practice on something else first --as I see you said you would.

Here's a fairly good primer about it, if it will help:
http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.easynet.co.uk/_chrish/t-solder.htm

Brazing would be a better with more open fault areas, but it also can flow into cracks, but the silver solder is quite a lot easier and probably better suited to the task you have.

Be sure to report the outcome --even if something goes not quite the way you want (I think it will go just fine, but if it doesn't don't give up hope --learning is like that and there are lots of helpful people here).

hal9000
06-13-2012, 03:39 PM
Thanks + or -.

I've been soldering and welding on an ameteur level for about 25 years and used to be a professional jeweler (different scale, but great way to learn heat control and soldering technique!). This isn't going to be that challenging, but I AM worried about the cleanliness factor. Not being able to get into the cracks to clean out any rust/oil in there leaves me less than comfortable. All I can think to do would be a) clean the item in an ultrasonic with some kind of rust/oil solvent, or 2) clean with acid. That's probably the most common/appropriate but I've never done it before silver soldering or brazing so not sure about the effects...

+ or - Zero
06-13-2012, 05:14 PM
Thanks + or -.

I've been soldering and welding on an ameteur level for about 25 years and used to be a professional jeweler (different scale, but great way to learn heat control and soldering technique!). This isn't going to be that challenging, but I AM worried about the cleanliness factor. Not being able to get into the cracks to clean out any rust/oil in there leaves me less than comfortable. All I can think to do would be a) clean the item in an ultrasonic with some kind of rust/oil solvent, or 2) clean with acid. That's probably the most common/appropriate but I've never done it before silver soldering or brazing so not sure about the effects...

I think you've got it, all in the ultra sonic (as you have it available and would be best practice any time possible), water based cleaner (simple green or the like), then rinse well, then etching (acid based) cleaner, then water rinse (repeat water rinse til water stays clean), solder without major delay.

If solder flows through the cracks to the inside of the threaded holes (to the extent possible) you've done about all there is to do, and should have an excellent repair after cleaning the threads and being sure the flat surfaces are flat.

I say that based on it not appearing from the photos that the threading is so distorted that it could not just be chased after the repair and still have an adequate fit.

It does seem that some flattening of the raised areas will be required anyway, and as the whole base really needs to be true you will have need of ensuring that. --a sort of separate question as to how best to do/insure that, after the cracks are repaired.

hal9000
06-13-2012, 06:20 PM
It does seem that some flattening of the raised areas will be required anyway, and as the whole base really needs to be true you will have need of ensuring that. --a sort of separate question as to how best to do/insure that, after the cracks are repaired.
I was looking at that and think that it could be kept functional without flattening. The area that is raised is the inner ring that's inset a mm or so from the actual contact surface and I don't think it would touch the cross slide. If it does need to be flattened, maybe I could do it in the little atlas mill that I'm finally picking up this weekend. That's probably more accuracy than is needed, but good practice.... I'm actually more concerned about the concentricity of the holes for the wedge pins. They'll be a bit oval unless I fill and re-drill them. Probably a non issue but I'm not sure.

+ or - Zero
06-13-2012, 06:46 PM
I was looking at that and think that it could be kept functional without flattening. The area that is raised is the inner ring that's inset a mm or so from the actual contact surface and I don't think it would touch the cross slide. If it does need to be flattened, maybe I could do it in the little atlas mill that I'm finally picking up this weekend. That's probably more accuracy than is needed, but good practice.... I'm actually more concerned about the concentricity of the holes for the wedge pins. They'll be a bit oval unless I fill and re-drill them. Probably a non issue but I'm not sure.

Yep, that's the problem with just looking at photos, but I figured it was best to mention it just in case.

How oval the pin holes are may, or may not, present a problem, that is true. My only real suggestion there is to do the repair and try it out. Problems, if any, would become readily observable and would still be fixable.

It's also worth noting that these aren't designed for super heavy work, stay within the design of the machine and it will be a really good little workhorse. They tend to be underrated by virtue of people comparing an Atlas 10 to a SB Heavy 10 (just as an example). You know the old saying; "it is what it is" --but that does not make it bad, it just makes it what it is. I love my Atlas 10 --for what an Atlas 10 should do, no more, no less.

Keep us informed on the results.

Gary Paine
06-13-2012, 07:18 PM
I was looking at that and think that it could be kept functional without flattening. .... <snip> the wedge pins. They'll be a bit oval unless I fill and re-drill them.

You're getting some pretty good advise, I think, but at the point when the solder is flowing and protecting yourself from any spattering, I'd use the broad end of a ball pein hammer to tap the deformaty back into shape. Cleaning it while the cracks are open is right, reforming, done hot, should close the cracks and excess solder will expell when tapping. You may want to do one side at a time. Cast iron is brittle, and with a larger breakage, I think cracking out a chunk would be a risk, but if I read this correctly I think you can get away with it just fine in this case. Then the holes will be back as they should be.

+ or - Zero
06-13-2012, 09:32 PM
You're getting some pretty good advise, I think, but at the point when the solder is flowing and protecting yourself from any spattering, I'd use the broad end of a ball pein hammer to tap the deformaty back into shape. Cleaning it while the cracks are open is right, reforming, done hot, should close the cracks and excess solder will expell when tapping. You may want to do one side at a time. Cast iron is brittle, and with a larger breakage, I think cracking out a chunk would be a risk, but if I read this correctly I think you can get away with it just fine in this case. Then the holes will be back as they should be.

Good point, I forgot the tap step, I always do that when trying to fill small cracks (braze or solder --I just spaced it I guess, Good Catch!)

But I had not considered the truing back into place aspect --I was just too focused on truing via some form of machine work later --So an even better catch!

Thanks, I love to try and help people, but I like it even better when some one points out something I didn't think of --I learn stuff that way!

hal9000
06-14-2012, 02:19 AM
I would NEVER have thought of tapping the CI back into place on my own. These cracks are pretty small so the movement would be minimal, but it's a great idea nonetheless. Thanks.

In all liklihood I'll wait a few weeks to do the repair. I've still got one craftsman 12x54 lathe that I need to try to get sold (the donor that the mill came with), and the atlas mill to pick up and assemble in addition to my normal job and home duties. More than enough to keep me busy. I'm just asking now so I can stay motivated to do something about it.

Thanks again guys.

+ or - Zero
06-14-2012, 03:00 AM
More then welcome, just let us know how it came out when you do get to it --I've been following the other thread also... you do need to watch out or you will end up with way too many high priority projects... Humm, I think I resemble that remark. Actually I suspect everyone here does also.

But look at it this way (it's actually from a cartoon, but pretty on point anyway); "God put me here to accomplish a certain number of projects... and I'm so far behind now that I'll get to live forever."

The one part of that I'm sure of is, just based on current projects, if I do get to finish them all, I will indeed live forever --or maybe a little longer...

good luck.

hal9000
06-14-2012, 11:45 AM
"God put me here to accomplish a certain number of projects... and I'm so far behind now that I'll get to live forever."

I think that will have to be into my new motto! :D

Actually, I've been trying very hard for the last few years not to pick up any new "big" projects until I get the current ones off my plate (that being finish remodeling my house/building my garage, finish building my race car, finish rebuilding my bronco)... But the "little" projects seem to keep me away from the big ones pretty effectively.