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Benchstar 16 Spindle

Cjc902

Cjc902

New Member
Good Evening,

I have acquired a benchstar 16 drill press in good shape. I hoped it give it a little TLC and have a good machine, however on disassembly I discovered that the spindle is bent.

Does anyone know of a parts list, or another spindle that will fit the machine?

Or is it just junk?

Thanks
 
HI,

Here are a couple photos of the spindle and the drill press itself. I don't know who manufactured it, which is part of the issue. It seems to be an old Taiwanese manufactured press. Probably from the early 90s or late 80s (according to Google)
 

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Cjc902 said:
HI,

Here are a couple photos of the spindle and the drill press itself. I don't know who manufactured it, which is part of the issue. It seems to be an old Taiwanese manufactured press. Probably from the early 90s or late 80s (according to Google)
Click to expand...

@Cjc902: Unable to read the manufactures number which could easily provide a hint. Could you provide that info from the Mfg plate?

Perhaps you don't have a lathe, my thinking is why couldn't you make a new spindle appears straight forward to me.
 
@Dusty: Unfortunately I do not own a lathe, having one made has crossed my mind, but I wanted to see if I could locate one first. The machine shops in my area that do that work are extremely expensive.

Straightening it has also crossed my mind, but it seems difficult to impossible to do it accurately without a lathe as well.

The mfg number is 86962. It looks more like a serial number to me. That's the only number on the machine as well. I do not think the motor is original as it is from a Canadian manufacturer. I attached a photo of the data plate on the motor anyway.
 

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How badly is the bend?
Is the bend in the middle or at the drill chuck end?
Replicating the shaft is a bit of a challenge because of the splines.

It might be possible to machine out the "bend' if it's at the drill chuck end.

If the bend is in the middle, a few carefully calibrated whacks with a hammer might do the trick.
 
@mikefrost: The bend is at the chuck end. It's severe enough to not allow a drill to run a straight hole and is visible with the spindle running with the chuck removed. I didn't measure it because it was so visible.
 
That's good news, I think.
Now, all you have to do is find some one to mount in their lathe, in a 4 jaw chuck, and take a skim cut to clean up the taper so it is straight with the rest of the shaft. Using blue dye you will be able to make any final adjustments to the taper, and a final step, lap in the chuck with lapping compound.
Where are you located?
 
Here is what I would do.

If the bend is only at the very end, possibly from the DP with chuck mounted getting hit hard say as in a fall, I would use a TIG welder (preferably) to build material onto the spindle end.

Then with a lathe I would re-machine the end. Note the spindle end appears to by a JT taper for chuck mounting - so its a small machine build to budget specs.

You can this way cut any JT taper you want.

Without a lathe it would be hard to fix this - you can try to cut it true while spindle is spinning in the DP and with a cutter in a vice. But this way you can cut non tapers only - so straight. You could try to cut a thread on a straight shaft and use a threaded chuck - like a chuck from a power drill.

There is no sense to use machine shop - cost to fix this is few times more then what the machine is worth.
 
@Cjc902 It could be that the chuck taper section is bent locally & the rest of the spindle is straight-ish. I'm trying to visualize a sequence of events where that could occur. Maybe some kind of lateral side load was imparted to the local area but the bearings/casting mostly hold the upper shaft straight in the upper assembly? The shaft is pretty meaty material so it would take some force. But it also could be that other issues are masking the problem. If the tapered surfaces between shaft & chuck surfaces are not an appropriate match, the chuck can cock up on the taper at an angle. It feels tight but that may not mean concentric. Then an extending drill exaggerates this runout. So the surfaces up & down the shaft should be checked elimination style. You didn't mention bearing condition or fit in the housing or shaft.

I helped a fellow out on a vintage drill press which was a different issue relating to fitting bearings with some constraints. But some of the pics might provide insight of how various surfaces can be checked.
canadianhobbymetalworkers.com

Need help with drill spindle!

Yes I've had good results turning aluminum CA glued to steel mandrel too. I have some (pop can) shim I keep handy & suspect it might be similar thickness. I'll try that test too. Thanks!
canadianhobbymetalworkers.com canadianhobbymetalworkers.com

If you take @dfloen up on his offer, I'd recommend you also send the bearings & chuck just so he has all the goodies. Assuming the issue is confined to the taper, I'm guessing it could be re-dressed to concentricity, but within limits. The more deviated it is, the more material has to be removed. Typically tapers are also defined by the big diameter, so that potentially affects the chuck fit to the point it may not anymore. But I'm getting ahead of myself. Getting it checked is step 1.

Lastly, I have a 90's era Taiwan bench style drill press. Maybe I got lucky but it is very accurate, low runout. One day I would like to VFD it because I think finding something mechanically as good might be more difficult. Some of the current drill press offerings don't look so great to my eye.
 
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Yes i'd want the whole spindle assembly with bearings and quill. Depending upon how bent it is, i can redress the grind, build it up and grind, or even convert it to a threaded chuck. Either way, save it from the scrap bin.
 
@PeterT: I really couldn't guess how it happened. The machine was stored for many years in a garage. Outside of this issue it seems extremely well built and the castings are very heavy. It has some sentimental value as well so I'd rather spend some money than junk it.

@Dusty: I don't know what taper the chuck is. I attached a photo of it anyway. The two lines appear to read:

2 1/2 AP EP
CAP. 0-1/2

It certainly needs to be replaced and I would take recommendations for replacement. Especially if the shaft is going to be reworked.
 

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First of all don't start machining anything yet. You are going to replace a few things but that comes later.

1. Reassemble it and mount the chuck.
2. Make sure its the press is bolted to something solid.
3. Make sure the quill is full retracted as the bend is likely (99%) just below the bearing and just above the chuck.
4. Take an indicator and determine the direct of the bend.
5. This is the scary part and requires some feel, wack it with a 2-1/2 hammer in the direction you want it to go.
6. Repeat 4, 5 and 6 until you got it where you want it (with a little effort you can get it within 0.0005" or less) within a few minutes no machining required. You are basically doing the reverse of what got it bent in the first place

Back to parts, new chuck (thats a given, even if it works due for replacemrnt), bearing(s) this is a bit of luck thing (check it) if they feel rough in the slightest, definitely! If not your choice, but assume you are going to at some point like it or not.

I have used this method and works extremely well.

Not into violence, the second method is torch (heat straightening), you will need a lath, a torch and a indicator. Spot heat the bend correctly the metal expands and pushes itself straight.
Haven't tried it but it is and old school trick, YouTube it (machinist is Ken Fenner I believe). BTW I would still replace the chuck.

 
Well folks, first off, thanks for all the help. I was just out looking at it all again and noticed a crack right at the flange below the bearing, never noticed it before.

I'd say it was dropped at some point in its life. It's a very fine crack but I wouldn't trust it....

Guess I got a bigger job or a new shop decoration.
 
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