I've been trying to extract some brass pilot screw out of some aluminum carb bodies. In the process i've broken a #1 twist type easy out off in the head of this brass screw. The head of the screw is about 1/4" down a hole in the body. I can supply a picture if needed. But I'm at a loss as to how to get this tool steel out. Is it possible to drill tool steel, if so what kind of bit can I use? Would it be better to use a diamond bit and a dremel to grind the piece out?
Before trying my extraction i soaked the screw hole with PB oil for 3 weeks, then drilled my pilot hole with the appropriate drill size in a mill then used a hand driver to turn my easy out. I was heating the casting with a small butane torch to help break it free and still it broke the easy out. Any help is appreciated. Thanks
A carbide drill will drill that right out, or an old carbide end mill will drill right through.
Good deal, I'll try that. I'm a Manufacturing and Industrial Technology major in TN and have access to a nice shop. We'll see if I can get some carbide tooling to work on my side.
A die grinder with appropriate burr may also work.
Many times, an EZ out is not a good choice where the original fastener is seized, and you must resort to drilling and re-tapping the original hole.
I'll keep that in mind as well, i have a few diamond and carbide burrs that I can try. I would have just drilled and retapped the holes butt the screws have threads that are so fine i've never seen a tap of this diameter with this thread. Know of anywhere that carries unique metric taps?
I totally agree with the crowd. Whomp it out with carbide. Indicate the center of the hole first. When the ezy-out is gone; drill the brass out with the size of drill that is for seventy-five percent the thread depth. An end mill is sometimes needed to start the first drill true. A solid carbide drill center is the cat's meow for making a center dimple. Since you say you have a thread above sticking up, the tap will just peel out the old screw threads from the aluminum. A plug tap will follow old threads better than a taper tap for these jobs. It is also more likely to 'catch' the original threads. I also say to chuck those tapered 'ezy-outs'. They cause more pain than pleasure. The parallel Rigid screw extractors are a thousand times better. They also come with left hand drills and pilots for getting to the middle of the problem.
I feel for you brother. I spend half of my life doing jobs like this. On average,I rebuild five updraft carbs a week and my right hand is getting numb from bitch slapping Engineers that have no buisness near tools. For carb jets and screws; I normally use the smoke wrench with freezer spray. The cool is more important than the hot.
Sorry.......... go to http://www.widell.com/ to get the odd stuff, in taps. They are my lifesaver. If they don't have it, they will make it. Their inventory must stretch halfway to the moon. This is the place guys like MSC, McMaster-Carr, and DoAll go for bastard taps. They probably made the original bastard size for your carb anyway.
By parallel Rigid screw extractor, do you mean the square sided tap in extractors, if not i've never seen what you mean. Glad to see someone understands the pains of working on carburetors. Thanks for your help.
If it's a totally unobtainium carb body, consider
taking someplace to get the offending item
Otherwise try the gentle application of a
carbide end mill as suggested. This MUST be
done in a rigid setup, in a milling machine.
Don't even *think* about using a drill press.
Keep the feed light and use some cutting fluid,
*not* lube oil.
My approach from the git-go is to drill to the
tap drill size and peel out the 'helicoil'
of thread left once this is done. If the
threads are already trashed I will make a
nylon or delrin plug to pick up the exact center
of the original hole (not the threads which are
trashed) and then re-tap to a larger size,
and make an OD/ID threaded insert which is then
green locktited in place.
They're not totally unobtainable carbs. But last time I looked they sell for $350 on ebay. It's a 1986 Yamaha Radian YX 600 rack of 4 carbs. It's an inline 4 engine. They're mikunis and there is only one other bike that uses these carbs and they're even harder to come by than the Radians. I actually had the carbs at a local shop to get the screws EDM'd out but they sat in the shop for over a month with no work done so i brought them home to try them again.
Ridgid screw extractors (Ridge Tool in Elyria Ohio) are round cylinders with straight ridge 'teeth' running down the length of the barrel. There is an adapter that slips on the extractor so you can crank on it with a hex wrench, or socket. You pound it in to the drilled hole and slip on the adapter. They do not deform the bugger as bad as those tapered, or square things. I keep a spray of freezer on the end and apply heat to the offending casting. I get twitchy when I must use 'the force'. Ridgid extractors include hardened centering plugs for the standard sizes. I have a homebrew set of tapered brass plugs for finding the center of holes. They are holed to my long shank center drills. JimRozen is also most correct to always use cutting fluid. I use filtered bacon grease, cut with ethyl alcohol, when going into such territory. In deference to Mr. Rozen; I use my Starrett pointy edge finder to find center, when possible. Mistress Bridgeport punches such pretty holes, in such an easy manner. Drill presses are for those too poor to have real 'hand' tools. I have to get one of those EDM things for home use...........
I have a huge assortment of custom ground screwdriver bits for carb work. They are mostly ground from M2. I find M2 holds up better, to hillbilly brass hammering and twisting, when one end is fourty below and the other end is jammed tight in a brass seat that is in a red hot Marvel-Schebler TTX iron carb casting. Regular bits tend to cam out or slip, because they are tapered, or just don't fit snug enough. Most steels also tend to snap off half way down the hole, from thermal shock.
If you are going to work on such stuff, you had better have a lot of bastard taps too. It is a sad day when I know to call 1-800-237-5963 and ask for Hank from memory. When you know the number of Widell tap from memory; you got it bad.
Yes; I do tend to get wide eyed and a bit nutty when I am working on old iron. You should see me when I am caressing......er.... I mean working on an old South Bend or Twin City.
Keep em' flyin'
Here's a thread about removing a bolt which had a drill bit broken off in it. Maybe the idea will work for you. bolt removal thread
One other technique that sometimes helps is to attempt to break up the easy out with a very small drift punch.
It may not get it out, but it can sometimes provide you with a flatter top exposed surface from which to start attacking it in other ways.
I use carbide drill but clamp a piece ground toolsteel with the correct dia of the carbide drill in line with the hole this ensures that easy out is drilled and not the side. Hope it works for you.
Was just wondering ,there was a thread a while back on this board or the other one about using "alum' to remove a tap in aluminium. would this process work in the brass screw?
I would think a taperer LH spiral type easy out in a soft brass screw would tend to expand the screw and make it tighter. After all it does work by wedging itself into the hole you have drilled in the screw. I would have used a LH drill bit as large as I could if I was sure it was lined up parrallel to the hole
I was thinking about that, the tapered twist type easy out expanding the screw, thus making it tighter. So this week i'm going to try the other routes of drilling and retapping if needed in order to get this job done. I'll let you guys know what route I end up taking through completion.
Chemistry using concentrated (NOT dilute) nitric acid should not attack the aluminium, but will attack everything else. Should be clean of oil and protect any brass or steel parts from acid spray, and do it outside, but probably you'd not be able to get conc. nitric unless you have contacts, and if you did you'd probably know what precautions to take - don't think of it unless you do........
- Mike -
Alum, saturated solution in water, soak the carb body, as long as you have removed all other iron screws and components, all you will have left of the easyout will be some sludge.