installing quil on mill drill

[elewayne]

Thanks Harold for your comments. I'm going to do just that in checking the shaft for bend. Fortunately most of the critical surfaces (ways) on the machine were oiled up enough to not rust that much. Mostly thick gunk and dirt. all screw heads and knobs and stuff were another story though. The machine has never been outside in the rain or anything, its just extremely humid here and surface rust is a constant problem. I doubt my cleanup efforts have effected whatever accuracy it had to begin with, by much, I was pretty gentle with it. And I do have an arbor press someone gave me recently. I was trying to think how to do a bend and forgot all about having it. too funny. thanks for mentioning that.
Would you heat the part first or just cold bend it? If that even my problem?

[Harold_V]

Damage from rusting isn't due to cleanup. It's due to the rust itself. It is highly unusual for rust to be consistent in depth, and any material removed from a critical surface causes a change. You most likely have done the best you can, and that's all you can do unless you rebuild the machine. That's a daunting task for a novice, assuming you understand what rebuilding means. It does not mean painting the machine to make it shiny. Fact is, painting has nothing to do with a rebuild. A machine tool can be rebuilt totally and not painted. I've seen that done.

As far as any bending of shafts goes, unless you are proficient at heat bending, don't use heat. Unless you heat to redness, it won't help much, and if you do heat to redness, you'll just damage the shaft (scaling), all for no good reason.

The corrections I mentioned should be done cold, so you have control of your actions and can take the required time to orient the part in relation to the press. How much effort it takes to make minor changes will be determined by many factors, including the spacing of the blocking upon which you place the shaft. Just keep in mind that any place it makes contact with the press is subject to deformation (denting), so use aluminum at all contact points. Spread the bottom contact areas to decrease pressure required to bend. Keep the spacing central to the ram, where pressure is applied so the existing bend is removed uniformly. If you favor one side, you'll introduce a new kink. It often is helpful to place limit blocks, so you can't press beyond a given distance. It's really hard to get a shaft back to its original condition if you work blindly.

H

[Patio]

Pictures are worth a thousand words. If you can, post a couple of pictures of the setup.

[elewayne]

Harold, thanks for the further comments. I'll follow the advice. I had a petty good idea what you said was true anyway.
First i will check the shaft between centers, as soon as I can finish a Christmas project here.
And I get using the aluminum blocks and spacing relative to the high point. I hadn't thought of a limit block though.
I do get the rebuild comments. all I've done is clean it up. Critical surfaces were still pretty oily and free of rust. The table is in factory condition. no one has even drilled a bunch of holes in it. How is that possible on used equipment?
After use, I will likely find other projects to do on it. It is Chinese, Harbor Freight after all. Sort of a project kit.

I'll get my son to help me figure out how to post pictures too, over the holiday. I have so much trouble with that sort of thing.
Merry Christmas to you and yours. thanks again.
Wayne

[spro]

Within this topic are many clues to straightening shafts. When mentioning your machine is around 1700 lbs. I sort of bailed out of the conversation. It is a "milling machine" not a mill/ drill. However; many of these m/d s have huge heads which could not be considered to mount to a compound swivel tilt knuckle on an extending ram.

[elewayne]

OK, the holidays over and things back to normal. Happy new years to all just a bit late.I have removed the horozantal shaft from behind the quill that the drill press handles mount onto. I have finally figured out how this is supposed to work. There is a bell or flower pot shaped piece on that shaft, right off the side of the head and through the fine adjustment casting. The cast hub with the three handles for the drill operations is the last piece, along with a hand knob to freeze the press handles on the shaft, for when you need to drill.
The outside end of that shaft is about 5" long at 1" dia. that bell shaped piece slides onto the shaft end and is about 41/2 " long. It has two holes in it and the front hole, the first end to go on the shaft is a good machined fit maybe a bushing too. The rear hole is just drilled into the cast iron.
Cleaned up now the front hole goes on about half way cleanly and turns freely but the end of the shaft bumps into the inside edge of the rear hole. the line up is just a hair off. I can force it on, but then it barely turns on the shaft like its supposed to. So checked the shaft using my lathe and its reads about 5 thousands bent. The shaft is 1" for the first 5" then the rest of it is about 1 1/4 in dia.so there is a shoulder there, and that seems to be where the bend is.
So do I try to straighten the 5 thousands out of the shaft, or maybe make the rear hole just a bit bigger for line up. I''m not sure how critical the second hole is. It wasn't treated in the same manner as the front hole. would cause backlash on the quill somehow? One of the handles is bent too so maybe it got hit there sometime or damaged during a move. I was very careful, but I cant speak for its past.
I hope that makes a bit of since. sorrily if it doesn't. I need to figure out the picture thing soon.
wayne

[Russ Hanscom]

Try to straighten the shaft. Plan B, turn a new one. Enlarging the hole is not a good idea.

If you have access to a hydraulic press, you can probably straighten it enough to make it fit properly. Support the ends on blocks of wood or aluminum and put another block at the end of the larger section. Mark the high side with chalk or marker.

Press a little bit - then test for straight - press slightly more, repeat until you get an idea of when bending starts. If you over bend a bit, start over. it usually takes a bit of effort for bending to actually start, then it can go quickly .. There will be a lot of spring in the part and press.

If you do not have a press, people can get pretty creative with some metal bars and a few bolts.

[pete]

If I'm reading your description properly your talking about the shaft that has the pinion gear on it right? With that shaft bent it try's to force the pinion teeth deeper into the rack teeth on the back side of the quill. Since the already low clearance between those two parts wont allow that to happen the assembly can only rotate so far before it locks up. Most of the machines I've seen the shaft and pinion gear is usually machined from one piece, not all though. Maybe double check for any set screws or cross pins holding the pinion gear to the shaft. If you get really lucky and that's how yours is then making a new shaft should be easy.

[elewayne]

thanks guys, That is the shaft I'm talking about, Pete. I wish I could figure out how to post pics on here. It is indeed milled from one piece. And I'm in no way a real machinist. Just starting to play around with this. I could probably turn the shaft but cutting the pinion gear would be a stretch. I do have a press and will try to bend the shaft carefully. I'll do a bit more measuring and see what I come up with.

[Harold_V]

It's not difficult to post pictures on the board. They can be hosted on the board, or elsewhere, with a link included in your post. However, considering the likelihood that the source can (and most likely will) go away, you are best served uploading them to the board. If you'd like to do that, it's quite simple. Follow the instructions below.

Just below the box in which you type your comments, there's a couple buttons (left hand side, assuming you're using Allan style Subsilver as your board choice). Simply click the one that says Attachments, and follow the instructions. Note that the picture should not be too large, so it spreads text. That makes all posts on the same page difficult to read, requiring readers to scroll left to right to do so. Also, be mindful that overly large files aren't a good idea. A picture that is sized 1024 x 768 pixels that is a couple hundred kb in size will provide quite good definition. If greater detail is required, the file size can be increased accordingly. Oversized pictures will be rejected by the board software. The picture(s) you upload will be presented as thumbnails, which can then be clicked to be seen full size.

I hope this helps you. If not, feel free to ask for guidance.

Harold (moderator)

[elewayne]

Thanks on the photo information, the boys will be over tomorrow and and we'll figure out how that works. But in the meantime.

I have the shaft on my lathe between two centers. and I started turning it with a dial indicator on it again to mark it. The end, at the lathe head, is within an thousandth, So okay, I guess. The other end, at the tail stock, is reading out 9 thousands off. So I'm thinking, either the shaft isn't round, and i don't know how they would accomplish that on a lathe, or, the hole is off center. (For its purpose it's not really necessary to be centered exactly).
This is the issue with Chinese stuff, I know.

So I'm just reading the amount the hole is off, not bow in the shaft, aren't I? At least not entirely. So, I'm thinking turn the shaft around and put the off center end in my four jaw and true it up. Then put the other end on the tail stock center. Close to the centers the shaft should run pretty true, right? As long as the hole is centered. Even if the shaft is bent. There's nothing wrong with my thinking here, is there?

[Harold_V]

Assuming you're placing the indicator at the extreme end of the part, I agree that the center is not concentric. If the part is ground, it may have been ground in a centerless grinder, so while it may (or may not) be straight, the center has no relationship to the grinding process.

I worked in precision grinding for several years. One thing you learn early on is that parts with centers, unless they have been lapped and used to finish the surfaces, may not, and usually are not, concentric with the surfaces. That's due to the fact that when you start a center drill using a lathe, it rarely is on true center. If you allow the center drill to float slightly, it will seek center, so you'll be quite close (usually within a thou), but if you force the center drill, it may pick a location far from center, so if the quill of the tailstock floats, you'll drill an eccentric center hole. For that reason, it's wise to snug the lock on the tailstock when you're trying to precisely locate a center, and, also, to grip the center drill by a very short portion, so it is free to oscillate in the chuck, to find center. It will if you allow it to do so.

Your idea to bore the center is spot on. Once established, they are virtually impossible to move by other means. Just ensure that you dial in the part in two directions. It's important that the shaft be parallel to the spindle centerline, as well as concentric to the centerline.

H