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View Full Version : Get'er out job on a simple drill press - how to reverse the spindle direction?



Euph0ny
10-06-2015, 06:31 AM
I have a small get'er out job to do - a stuck grub screw, whose previous owner rounded out the drive hex.

Since Plan A (soaking in penetrating oil) and Plan B (careful persuasion with a centre punch and a hammer) have failed to shift it, I'm going to "Plan C" - left-handed drills. I got a nice boxed set of those from www.Projahn.de

Alas, my cheap drill press at home doesn't offer a reverse spindle direction. It's a "King Craft KTB 400", that I bought from Aldi in Germany years ago - pretty much the same ubiquitous Chinese unit available from HF in the US and elsewhere. As it happens, one identical to mine is on sale in Germany now:

http://www.ebay.de/itm/King-Craft-KTB-400-Tischbohrmaschine-Standerbohrmaschine-119428-/151837040561?hash=item235a315fb1

So, my question - is there a simple way to get reverse on this unit? Perhaps a reversing switch I could add? It would save me the trouble of taking my tiny project to the big mill/drill at work, and maybe make my little drill press a bit more versatile too.

Thanks!

awemawson
10-06-2015, 06:34 AM
As an alternative, can you place a nut over it, and mig weld through the nut to the grub screw, then unscrew it using the nut? Sometimes helps to put a washer over the hole to stop marring the surface.

Euph0ny
10-06-2015, 06:51 AM
As an alternative, can you place a nut over it, and mig weld through the nut to the grub screw, then unscrew it using the nut? Sometimes helps to put a washer over the hole to stop marring the surface.

Thanks. Ordinarily, that would be an option (as would the "blue wrench", regular drilling for EZ-outs, hammering in a Torx bit, etc., etc.).

However, (a) I don't have a mig welder or access to one, and (b) the grub screw is stuck in a fairly delicate part of a firearm, the temper of which I don't wish to risk affecting with heat. I'm hoping that careful application of LH drills might turn the screw out, and if not, I'll have to drill away enough of the screw body that I can pick out the remaining threads before running in a tap to deburr the tapped hole. Fortunately it's not teeny-tiny; about 6mm / .200".

MrFluffy
10-06-2015, 07:38 AM
Can you not just cross the belt between pulleys for the duration of this one job? Sure it'll rub against each other at the point of crossing but I've done it in the past in a emergency with a single phase dp that had no reverse and both dp and belt survived just fine.
If not, you are into altering windings and things to make it go backwards, someone else will have to steer you through that if possible.

kitno455
10-06-2015, 07:43 AM
Sure- open the connection box on the motor, and see if there is a diagram. In particular, trace the wires that come from your mains power, and see what they are connected to. look for labels or numbers on the wires, and let us know.

allan

michigan doug
10-06-2015, 08:06 AM
clamp it well in a vice and use a hand drill.

As noted previously, drive in a torx with a hammer--gently.

bborr01
10-06-2015, 08:08 AM
Why not use a hand drill that is reversible? Run the drill fairly slow and the LH drill will want to grab and turn it out. I have done this many times and it works well, most times turning the screw right out.
Just make sure you have it aligned on center.

Brian

Euph0ny
10-06-2015, 09:11 AM
All, thanks again!

Hand drills - yes, running a handheld drill anticlockwise is the ultimate backup option, but I would really prefer the stability and controlability of using a spindle downfeed handle. I'd probably take the setup to the mill/drill in work before going handheld.

Crossing the drive belt - I'll have a look and see if that can work on my machine. It should, if the belt is long enough and/or there's enough adjustment in the motor mount.

My curiosity is getting the better of me - now I'll have to dig in and check the motor winding/wiring...

Toolguy
10-06-2015, 10:07 AM
For the crossed belt you can probably put one end on a smaller step of the pulley to make up for the reduction in length.

Illinoyance
10-06-2015, 12:25 PM
Don't know about your motor. Most single phase motors can be reversed by switching leads. See if that is an option for your motor.

spongerich
10-06-2015, 12:59 PM
I have some square Proto easy-outs that work pretty good on stripped socket head screws. They jam themselves in a lot better than the spiral ones.
If it's not completely stripped, you might take the next largest size allen, grind it down just a little until it barely fits and hammer it in. Then use a hand impact driver to reverse it out.

old mart
10-06-2015, 01:02 PM
Check that the chuck will stay secure if you can find away of reversing the drill press.

Paul Alciatore
10-06-2015, 03:18 PM
"Curse you, Red Barron!" Now I am thinking about how to add a reverse option to my drill press.

AS IF I DIDN'T HAVE ENOUGH PROJECTS.


Oh! My mill does reverse and that job could be done there with no changes. Perhaps I can forget that drill press project.

Norman Bain
10-06-2015, 03:42 PM
To reverse direction of spindle create a twisted belt out of some of that round drive belting.

Euph0ny
10-07-2015, 04:15 AM
"Curse you, Red Barron!" Now I am thinking about how to add a reverse option to my drill press.

AS IF I DIDN'T HAVE ENOUGH PROJECTS.

My most humble apologies ... but could I perhaps borrow your mill? :-)

Seriously, this drives home to me that I need to give some serious thought to finding funds for a "proper" mill for the wee home workshop - at least it would keep the lathe company.

Euph0ny
12-04-2015, 07:16 AM
A quick update on this job. It became urgent, so I didn't fiddle around with setting up my drill press to reverse. I used left-hand drills in a hand-held cordless drill.

The hex-socket part of the set screw/stud was very hard, to the extent that the drills wouldn't touch it. However, once I had eaten away to the depth of the socket with a carbide burr, the drills cut through the rest OK, though it still stubbornly refused to unscrew, so I had to drill out to the major diameter of the male thread and to the full thread depth to get the captive part released.

Now I have a wallowed-out hole for a setscrew, with no threads left therein. I will see if a thread-repair coil makes for an acceptable recovery; it'll work OK to hold the part, but I'm doubtful about the aesthetics on an exposed part of a firearm. If not, it'll have to be filled with tig weld, re-drilled, tapped and re-blued.