Suggestions on straightening drill press spindle?

[v7guy]

Was buying this Dunlap/Atlas/Craftsman drill press from a fella and when he picked it up to put it in the back of my truck he dropped it and it landed on the spindle. He told me "it looks like you got a free drill press". I gave him $10 and took it home figuring I could probably fix it with some work.
Here's what i have to work with...

Got it disassembled and this is the damage...

I've read about using a press and some kind of v block to get run out in the thousandths but i haven't been able to find any real details and dont have a v block.

I've also found a few potential replacements on ebay... but i'd rather repair than replace if possible.

 

[lilredex]

Looks as though it bent on the top half, so it needn't be perfect. I'd roll it on a flat surface and mark the highest spot. If you have a vise, cut a couple of sturdy angles (2" X 1/4") and weld V-eed blocks about 8-10" apart on one and weld another V block in the center of the other length. Put the angles in your vise so the single V block pushes about center on the other. Put your shaft in there and straighten it.

The V blocks can be a section of angle bolted in if you have no welding.

Should be able to get it good enough this way.

 

[Outlawmws]

find a dead flat surface and roll the "business end" on it with the bent part hanging off the edge. I'd guess while most of it is at the pulley end, there will be some wobble in the business end.

If so, I think you are better off getting a replacement if possible.

A well equipped shop could get it straight, but you really need some good setup and measuring equipment to do so.

 

[trboxman]

Have your local machine shop quote machining a replacement.

 

[v7guy]

lilredex- I can weld up some angle, that sounds like a reasonable approach.
My worry is that as the spindle plunges the pulleys rise on the shaft and it gets more out of wack. Right now I can't fully plunge the drill press because the spindle is bent. I'm also concearned about putting more stress on the bronze bushings.
I'll give it a shot, I don't really have anything to loose at this point.

Outlaw- the business end appears to be true, but I don't have anything that I know is dead flat.
It's looking to be a pretty hard part to find, I've been tossing around asking a few members if they could machine one. But I think I'd be getting into some money going that route.

 

[pop pop]

Find a good local machine shop. They'll have more equipment if you don't. It can be repaired. It is no more difficult than a ****** mainshaft.

 

[Lightfoot]

pagin A_PMECH, Pmech to the house phone please.

 

[v7guy]

pagin A_PMECH, Pmech to the house phone please.

lol, he was going to be the first one I pm about machining a new one if I couldn't fix or replace.

Just picked up some angle.

 

[rlitman]

Whatever you do, do NOT try to lay it flat, high side up, and press the high side back down. If you do that, you will introduce a bend to the bottom half of the shaft that is still straight. Does this make sense? It looks like the whole shaft is bowed, but it is not.

What I would do, is grab the shaft between wood blocks in a vise, clamped near the base of the splines (at the bottom of the bend, so that NO force is applied to the part of the shaft that is still straight), and go to town on the end of the shaft with a dead blow hammer. Since it's just the pulley end of the shaft, if you get it as straight as your straightedge, you'll be fine.

 

[rsanter]

the only way I know that will do it reliably without causing a further problem is to put it in a lathe (the bigger the better) and clamp it in the chuck as close to the bend as possable. the use an hydrolic jack as close to the bend as possable to push on it to straighten it
keep working it little by little untill you have it right

I have straightened boat prop shafts that way

of course the best bet is to buy a raplacement if you can

bob

 

[USMCdodge]

that could be made by a machine shop fairly cheap i would say. its all pretty basic stuff. check out a shop before you buy a replacement for sure

 

[GRX]

If I were you I would call the local machine shop.

At work I would employ the hydraulic crank shaft straightener and check with a dial indicator.

 

[back2class]

would be very easy with a small shop press. Just go a little at a time and it will come out perfect or close enough to it to be good to go.

 

[Provincial]

Do not try to straighten the spindle until you reassemble it into the quill housing. The bend was introduced while the spindle bearings were supporting the spindle, and you cannot successfully straighten the spindle unless it is supported exactly the same as it was when bent!

You will need to clamp the quill solidly to a work surface and set up a dial indicator to measure the wobble at the extreme end of the bent (pulley) end of the shaft. To make it easier to use the dial indicator, it would be best to press a round sleeve over the shaft at the measuring point so the indicator has a smooth, round surface to run on. Rotate the shaft an determine the extreme maximum deflection. Apply pressure toward straightening the shaft as close to the point where the force was applied that bent it, taking up the bend in small increments. As you get close to straight, you will have to deflect the shaft past straight to make up for "spring-back" using the dial indicator to keep track of the travel as you apply and remove the force. You should be able to get it to run true within a few thousandths of an inch.

Using this method you should not end up with any bend at the chuck end because as you straighten the drive end you are applying force to the chuck end in the same fashon as when the damage was done.

Straightening shafts is actually fun once you get the feel for it. I have straightened hydraulic cylinder shafts that had complex bends, S-bends, and bends in more than one axis. You have to use the dial indicator (sometimes several indicators) to determine where the bends are, mark them with Sharpie or grease pencil, and adjust your v-blocks and press ram to work them straight a little at a time. Complex bends require going back and readusting your prior work as the next bend(s) change the stress on the earlier work.

This is not fun if you lack patience!

 

[v7guy]

would be very easy with a small shop press. Just go a little at a time and it will come out perfect or close enough to it to be good to go.

How would you do it with a shop press?

 

[trboxman]

I'd be worried about cracking the head casting while trying to straighten it mounted back in the drill press...and I'd certainly be worried about destroying bearings not meant to take a side load.

 

[back2class]

How would you do it with a shop press?

Block it up properly and bend down the high spot past straight to make up for springback as another member mentioned. Little at a time. I've done quite a few shaft straightening jobs in my little 12 ton press. Takes a little understanding of how to work the steel and where to block it, but this is not a difficult job.

 

[v7guy]

To get it to the point it's at i had to persuade it a bit while still in the drill press. I'll see what i can do to straighten it with the advice given and see what happens.

 

[Provincial]

Jason, the quill is the tubular part with the gear teeth on it that the spindle runs in. It has the bearings inside. That is all I suggest to assemble, not put it back in the drill press housing. Did you take the quill out of the housing or just knock the shaft and bearing out?

 

[v7guy]

I took the quill out of the drill press too.
Haven't had a chance to tinker with this yet.

 

[A_Pmech]

Hi Jason,

I can likely straighten that.

I'll send you a pm tonight, my phone does not like sending pm's.

 

[A_Pmech]

Hi Jason,

I can likely straighten that.

I'll send you a pm tonight, my phone does not like sending pm's.