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garyphansen
03-10-2006, 09:22 PM
I would like to remove a screw that helps holds the saddle of my lathe. The head is buggered up. I ground a screw driver to fit but it will not budge. Would heat be OK or will it cause the cast iron to crack? Should I drill it and use an easy out. Any chance it is left hand? the outer one is right hand and will come out easily. Gary P. Hansen

wierdscience
03-10-2006, 09:29 PM
What about an impact driver?They work wonders on those stuck filister head screws Honda motorcycles love so much.

I also have punched a hole in a piece of sheetmetal,placed it over the head followed by a flat washer and then mig welded a "stud" on top of the head and backed it out with vise-grips.It ruins the screw,but avoids all the cussing generated by drill bits and easyouts and the sheetmetal protects the shinney surfaces from the welding soot,spatter etc.Hope that helps.

J. Randall
03-10-2006, 09:29 PM
If by outer one you mean 2 screws in the same hole, with the outer used to jam it, then both would be right handed. I would try an impact screwdriver if it were mine. James

torker
03-10-2006, 09:30 PM
Gary, I get all the used dental burrs that my denist will give me. I use them in a dremel tool for deepening buggered screw slots. Then I use an impact screwdriver to remove them.
I also have an old screwdriver with no plastic handle on it. I stick this in the slot and give it a good whack with a hammer to help loosen it up.
Russ

wierdscience
03-10-2006, 09:32 PM
<font face="Verdana, Arial" size="2">Originally posted by J. Randall:
If by outer one you mean 2 screws in the same hole, with the outer used to jam it, then both would be right handed. I would try an impact screwdriver if it were mine. James </font>

Oh man,the same idea,at the exact same time,from two different people on the same day http://bbs.homeshopmachinist.net//eek.gif we have just excluded ourselves from ever running for a seat in congress http://bbs.homeshopmachinist.net//biggrin.gif

garyphansen
03-10-2006, 09:32 PM
That should have read (other). Gary P. Hansen

garyphansen
03-10-2006, 09:55 PM
Torker: That's a good idea about deepening the screw slot. Then may be I will use a cheater bar on the screw driver. Does anyone think heat would be OK? Gary P. Hansen

Ted
03-10-2006, 09:58 PM
If all else fails, take a flat washer with a hole about the same size as the screw head, lay washer down over top of the head and mig weld. Then place a nut on top of the washer and weld the bottom of the nut to the washer. Take a wrench and back it out. I have removed many broken bolts this way. Just be sure and weld the washer to the screw head only!

Tin Falcon
03-10-2006, 10:03 PM
Gary:
Used to remove stuck scews from aircraft for the USAF/Air guard.
Clean dirt and paint from head. Get an apex bit to fit snug. Tap in if needed then use a speed handle with presure plate or chuck the bit in an old fashioned brace and bit. This will allow you to apply downward pressure to keep the bit from slipping out and alow you to put more torque on it than a screw diver. I very seldom used the drill and easy out. The real fun is the ones that someone broke off the easy out in.
Tin

darryl
03-11-2006, 12:20 AM
Russ's idea of impacting on the screw head to help loosen the threads has helped me out a couple times.

lbhgti
03-11-2006, 12:45 AM
What type of head did the screw have before it got all buggered up? What size are the threads? On allen head screws, I've had good luck beating a slightly larger torx driver into the head. The impacts from the hammer usually loosen the threads up a bit too. Heat will probably be OK, but use an acetelene torch so you can get a good small flame and concentrate the heat on the bolt head. Then when its nice and melted, kill the flame, drop the torch, and beat a torx driver in there before the metal freezes.

torx drivers don't seem to work for !@%# in the bolts they were made for, but they seem to work good for taking out all the other bolts.

Ian B
03-11-2006, 05:59 AM
Gary,

Not sure if this is directly relevant in your case, as your problem seems to be that you can't apply enough torque to the screw rather than the screwdriver is slipping out.

If you have the slipping problem, try this stuff:

http://www.alcoa.com/fastening_systems/commercial/en/product.asp?cat_id=1496&prod_id=1102

We use it offshore, and it's truly magical. It looks like a suspension of grey crystals, and a drop on a screw head feels like you've welded the screwdriver to the screw.

Ian

tattoomike68
03-11-2006, 01:32 PM
drill a small pilot hole in it then take a left hand drill bit (or right hand sharpend left hand ) and hog it in hard, it will grab and screw right out.

[This message has been edited by tattoomike68 (edited 03-11-2006).]

Wirecutter
03-11-2006, 01:36 PM
garyp -
I was curious, as I've noticed a similar problem on my lathe. Is yours by any chance a South Bend 9? (you may have said previously, but I don't think I could find the thread)

I ask because, if it weren't for the fact that I have a stuck screw, I may have done like CCWKen did.

http://bbs.homeshopmachinist.net//Forum1/HTML/015971.html

I got stuck with the screws that hold the apron to the carriage on the SB9. I have recently aquired a (manual) impact screwdriver, but I haven't had the nerve to take a hammer to anything touching the lathe. I'm also going to check for some kind of jam-nut or other locking mechanism that I've missed.

Anyway, please post whatever resolution you wind up with - inquiring minds want to know.

-M

thistle
03-11-2006, 02:53 PM
heat an appropriately sized steel rod red hot, hold it on the offending head to heat it.might work.
put screw driver blde in slot,use an appropriately sized chisel to gently move some of the metal back towards the slot. might work.


I often resort to the air hammer in desparation,but have to anylise what might bad things mighthappen care fully.
make a rod out of soft metal-brass or aluminium with a hole in one end to fit over the end of the hammers tip.
a few hits some times will loosen the most stubborn screw, a few too many and you will
destroy everything.

something about an air hammerwill loosen the most stubborn of stuck things.

garyphansen
03-11-2006, 04:50 PM
Wirectter: Yes, I have a floor model 9" South Bend Model A Lathe. I just bought a saddle, cross slide, and compound with large dials off E-bay so when it gets hear I want to replace my existing saddle. I think that will be easier than replacing just mycross slide, cross slide screw and coumpound, because to take out the existing screw I would need to use a hacksaw on it. Gary P. Hansen

garyphansen
03-11-2006, 04:54 PM
Thistel: Heating up a rod and using it to head the bolt is a good idea and I will try it. I should have though of that myself. Most likely would have a few years ago when I did more of this kind of stuff than I do know. Gary P. Hansen

Wirecutter
03-11-2006, 05:47 PM
GaryP -

Ah, so you're doing exactly what I was considering. I like that the model A has the option for power crossfeed, and of course, a quick change gearbox.

I wasn't sure about how much can be changed out, though. Shouldn't the carriage be matched to the bed somehow? It might not be such an issue with brand spankin' new parts, but after a little wear? I'm asking because I just don't know.

I think my cross slide and compound are ok, such as they are. I've had mine apart, but I couldn't figure out how to take the compound apart, just the cross slide. But I wouldn't mind upgrading the apron - is the carriage the same? Anyone know if this can be done?

(Ah hell, maybe I should think of getting a better lathe? I was trying to save up for a stuff for the Bridgeport, like ball screws, a DRO, or maybe a CNC upgrade, but... Geez, where does it end?)

Of course, the usual request - post pics of it when you're done, or at least give us a full report. http://bbs.homeshopmachinist.net//biggrin.gif

-M

garyphansen
03-11-2006, 06:08 PM
Wirecutter: Do you have a Model A,B, or C? There a lot of guys who have converted C's to B's or C's and B's to A's by buying and fitting Model A parts.

My Model A spent some time as a school lathe and has the scars to prove it. Long ago some kid decided to machine some extra clearance to the corner of the compound by using the chuck as a milling cutter! However, the bed on my lathe has almost no ware. The saddle I am buying is comming off a lathe with a neer new bed also. So, I am hopeing I can just switch them out.

panchula
03-11-2006, 09:11 PM
If the screw slot is too buggered to grab the screwdriver, I've had success with the following technique:
Use the largest screwdriver you have that will fit the slot. Put a dap of valve grinding compound on the end of the blade of the screw driver. Put as much downward force on the screwdriver as you can. Now when you go to put torque on the screw driver, do it FAST. Don't twist it like a regular screw where you give it a chance to ride up and out of the buggered slot, pop it fast like a boxer throwing a jab.

Usually, the screw will move. If it doesn't, then move on to more drastic measures.

I've removed screws that took penetrating oil, electrolysis, an air impact wrench, and an O/A torch with a rosebud tip before yielding. Both the casting and screw were saved in that particular case.

Don't hurry, don't get frustrated. Remember: You're smarter than the screw and more stubborn.

Wirecutter
03-12-2006, 10:04 AM
<font face="Verdana, Arial" size="2">Originally posted by panchula:
Remember: You're smarter than the screw and more stubborn.</font>

While I know this to be true, sometimes I really don't feel that it's true. http://bbs.homeshopmachinist.net//biggrin.gif http://bbs.homeshopmachinist.net//biggrin.gif

Wirecutter
03-12-2006, 11:01 AM
<font face="Verdana, Arial" size="2">Originally posted by garyphansen:
Wirecutter: Do you have a Model A,B, or C? There a lot of guys who have converted C's to B's or C's and B's to A's by buying and fitting Model A parts.</font>

I believe it's a C. No power cross feed, manual change gears. I have a QC box, new lead screw, yada yada, but I've had some trouble mounting it all up and getting it to work. Seems that there was a shear pin in the middle of the box that had - surprize! - been sheared. Also had to get my grubbies on the 20T gear that goes on the end of the leadscrew. Still don't have the 20T spur gear that drives the QC box, but there are ways around it.

garyphansen
03-12-2006, 09:56 PM
Wirecutter: A Model A has a driffrent apron (control for power cross slide) a drifferent cross slide screw, (splines to drive the power cross feed, and a drifferent lead screw (spline , the full lenght).

My bolt is still stuck, I may have to drill it out. Gary P. Hansen

tattoomike68
03-12-2006, 10:08 PM
try the left hand drill bit trick , I'v had a job that had 32 broken bolts in a flywheel , I got them all out in around 90 minutes.

Wirecutter
03-13-2006, 12:23 PM
<font face="Verdana, Arial" size="2">Originally posted by garyphansen:
Wirecutter: A Model A has a driffrent apron (control for power cross slide) a drifferent cross slide screw, (splines to drive the power cross feed, and a drifferent lead screw (spline , the full lenght).

My bolt is still stuck, I may have to drill it out. Gary P. Hansen</font>

Ah, so apart from the apron, I'd need the cross slide screw. I already have a slotted lead screw. Hmmm.

Duct Taper
03-13-2006, 04:55 PM
FREEZE IT
Use a torch to gently heat the surrounding area so that it is hot to the touch, no hotter. Then take an aerosol can of “Freez It” or they now have the same thing in drugstores for removing warts, I don’t know the brand. Use the little plastic nozzle tube so you can get a fine spray and spray the screw head really good until it shows frost. Then hit it with one of the hand impact hammer screwdrivers.
The gentle heat will expand the surrounding area and the freezing of the screw will shrink the screw in the hole.

HTRN
03-13-2006, 08:37 PM
<font face="Verdana, Arial" size="2">Originally posted by Duct Taper:
FREEZE IT
Use a torch to gently heat the surrounding area so that it is hot to the touch, no hotter. Then take an aerosol can of “Freez It” or they now have the same thing in drugstores for removing warts, I don’t know the brand. Use the little plastic nozzle tube so you can get a fine spray and spray the screw head really good until it shows frost. Then hit it with one of the hand impact hammer screwdrivers.
The gentle heat will expand the surrounding area and the freezing of the screw will shrink the screw in the hole.</font>

Radioshack used to sell "freeze spray" to instantly cool off overheated components, but I don't think they sell it anymore. CompUSA might still sell it, as might BestBuy. I know places like Digikey and Mouser probably sell it, but that involves shipping charges. Mebbe Homedepot sells it?

BTW, that stuff has another handy use: when you tear the head off a cartridge, and need to get it out, rather than use a case extractor, spray a little of the cryospray in the chamber, trying to get it only on the case. Then upend the rifle, and give a firm rap on the butt with the palm of your hand. 9 times out of 10, the case will fall out. http://bbs.homeshopmachinist.net//smile.gif


HTRN



------------------
This Old Shed (http://thisoldshed.tripod.com)

Duct Taper
03-14-2006, 03:10 PM
http://img.photobucket.com/albums/1003/dvonborn/Freez-It.jpg

This is what I use. FREEZ-IT. You can get it from Enco or MSC. Here is the MSC link:
http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=1657925&PMT4NO=5647855

garyphansen
03-15-2006, 11:01 PM
Well thanks everyone for your tips. I did not try any of the tips that included welding because I have no welding equiptment. I tried heating with out success most likely because of the different expanion rate of steel and cast iron I was afraid I might cradk the cast iron and did not get it hot enought. I tried deeping the slot with a carbide bur but my deeper slot just deformed. I tried the throax screw driver trick with no luck. I tried soaking it with several different types of oils, no luck. I tried tapping it with a small hammer, no luck. I tried driving around in a circle with a center punch and a hammer, no luck. Finally, drilled a 1/4" hole and used an easy out and that worked. Who knows, maybe I am smarter than a screw after all!. Gary P. Hansen