used drill press with runout (Rexon RDM-100A) ... what to do?

[gashford]

Hi All,

Well I've made my first mistake. I saw a great deal on kijiji for a 14" drill press and got it without checking the runout. This, in hindsight, was incredibly silly because I had a dial indicator from an old auto project sitting in my work room. Despite the sellers statements on condition, I could have easily checked.

Well, what's done is done. From the dial indicator, it reads a total runout of 9/1000" using a straight (new) 1" forstner as a test pin.

Doing a run of test holes using a fence, the exits are all over the place, which is not surprising given the randomness of the drill entry point.

So ... kinda crappy.

I'd like to remove the chuck to see if a simple cleaning will help, but I'm not exactly how to do this. I cannot find a manual for this press and the web seems to be completely devoid of any information on this model (inluding the REXON site). There is no slot in which to place a tapered wedge into for removal, so I assume that I'll use a couple of shims directly above the chuck. Does anyone know?

Any thoughts on what to do with this press? Make and model is REXON RDM-100A

 

[Engraver-60]

Take it apart and replace the quill bearings. If it was built, it can be dis-assembled.

 

[dsutton24]

Usually the chuck is a press fit on a tapered shaft. That tapered shaft may be a tapered insert into the quill, or the tapered shaft may be the quill itself. Open the chuck up fully, and look up into the chuck with a mirror and a strong light. You may find a screw that secures the chuck. If so, remove it (it probably has left hand threads).

Now, try to straighten the chuck. Raise the chuck to the full up position. Move the chuck around until the 'high' point is to your right. Place a brass drift against it (in the area where the chuck key pilot holes are drilled) and rap it with a hammer. Rap it, don't whale on it. Don't do this with your indicator on the chuck. Indicate it again and see if anything moved. If it didn't the chuck needs to come off. If it does move, continue tapping and indicating until it runs straight.

Lower the chuck to the full down position. If you see a slot cut in the quill, driving a wedge into the slot will push the tapered chuck mount out of the quill. If there's no slot, you drive a wedge between the chuck and the quill. The wedge for this job has a slot cut in it so that it straddles the chuck mount and applies pressure on both sides of the chuck. If you don't have a separating wedge you can use a pair of small chisels, tapping them evenly so that you don't bind the chuck.

Once it's off, polish both mating surfaces, reinstall the chuck, indicate it until it runs straight, and install the fixing screw if it has one.

 

[Teletubbi]

or go to Harbor Fright for a new $59 drill press?

 

[Glen Smith]

No Harbor Freight in Canada.

 

[R. Stratenstein]

Before you try any disassembly, have you tried using a bronze bristle (gun cleaning) brush to clean the chuck contact surfaces? When my good press starts getting wobbly, often it's crud that has made its way up into the chuck, or a spot of rust. I'll just blast some WD-40, or Break-Free CLP up into the chuck, open or close it until it's bearing on the brush, and give it a good scrub, then blast in some more juice to clear it out. Also lubes the chuck workings inside.

Also, when you chuck you bit in place, do you use all 3 holes around the chuck, and tighten incrementally, and with as even force as possible? Old trick my shop teacher taught us, don't know why it works, but it does make a difference for straight running.

 

[R. Stratenstein]

Also, that name plate looks very similar to the press I ruined by using it as a spindle sander. (But a different name) Side thrust stress ruined the bearings. Been meaning to disassemble it and see if I can get replacement bearings for the quill, but just haven't taken the time. Don't know if I still have, or can find the manual, but if I do, I'll get back with you.

 

[gashford]

I did also check the "runout" on the top part of the chuck itself, which is out by about 7/1000" ...

Thank you everyone for their suggestions. I will attempt to straighten the chuck described by dsutton24 above and report back. This one does not have the slot cut in the quill ... but I'll get to that if I need to take things apart.

R Strat - I have not attempted a cleaning with the chuck on, so I'll try that first.

Teletubbi - I just checked out the Harbour Freight website and wow you guys south of the (Canadian) Border have it good We have Princess Auto and Canadian Tire here, but they certainly don't have $69 drill presses.

Cheers!
Graham

 

[I_build_my_own]

Take it apart and replace the quill bearings. If it was built, it can be dis-assembled.

agree, if there is noticable wiggleroom when you push the chuck left and right with your hand, then get new bearings. If you get new bearings, try not to use the drill press as a spindel sander as that's what gets bearings killed in no time.

 

[Scrapperz]

Just in case your unaware. Whenever chucking a tool in that kind of chuck always gradually tighten the chuck using all three place (holes for the chuck key) as this is how the chuck was designed to be use. This gives the best centering of the chuck as well as grip on the tool.

Another tip: Oil on the tool shaft or the chuck will not be the cause of a tool slipping in the chuck, chips from the material your working with will though.

I've done precision work with worse run-out than that, and I'm talking millions of parts made of all types of materials. if it the tool wobbles too much slow the tool speed down as it will lessen the vibration and allow to have more control. Obviously if you still can't handle the tool find a better drill press and tools or learn more about craftsmanship. The more experiences you take on give you more abilities.

 

[gashford]

Just in case your unaware. Whenever chucking a tool in that kind of chuck always gradually tighten the chuck using all three place (holes for the chuck key) as this is how the chuck was designed to be use. This gives the best centering of the chuck as well as grip on the tool.

Another tip: Oil on the tool shaft or the chuck will not be the cause of a tool slipping in the chuck, chips from the material your working with will though.

I've done precision work with worse run-out than that, and I'm talking millions of parts made of all types of materials. if it the tool wobbles too much slow the tool speed down as it will lessen the vibration and allow to have more control. Obviously if you still can't handle the tool find a better drill press and tools or learn more about craftsmanship. The more experiences you take on give you more abilities.

Thank you for the tips. Do you have any suggestions for achieving precision with this amount of runout? I was able to achieve a decent row of holes when using a fence and a punch. Is this the right approach?

 

[Scrapperz]

Thank you for the tips. Do you have any suggestions for achieving precision with this amount of runout? I was able to achieve a decent row of holes when using a fence and a punch. Is this the right approach?

I would say if your using a punch your on track (look at my signature). Proper approach for precision drilling is measure and scribe your layout, center punch, center drill, and drill. The center drill funnel diameter needs to be slightly bigger than the finish drill in order for the drill bit to bore a hole very close to it's size.

More importantly, for your situation your "Forstner bit" has a guide in the center which makes it easier to get centered in a nice big center punch mark, want better accuracy and ease of cutting?, drill a pilot hole the size of the centerpoint of your bit to depth first then bore your with your Forstner bit. Bring the tool down slowly into the work, get that tool in its mark, if there's run-out your part will reflect that by wiggling a bit. When you assert pressure on the tool and engage cutting give steady pressure to form a nice continuous chip until heat builds up and release pressure to break the chip and repeat. I gottta go eat. Hope this helps. There many tricks up my sleeve as I have done a lot of precision work on machines 80-100 years old. Just ask.

 

[gashford]

I would say if your using a punch your on track (look at my signature). Proper approach for precision drilling is measure and scribe your layout, center punch, center drill, and drill. The center drill funnel diameter needs to be slightly bigger than the finish drill in order for the drill bit to bore a hole very close to it's size.

More importantly, for your situation your "Forstner bit" has a guide in the center which makes it easier to get centered in a nice big center punch mark, want better accuracy and ease of cutting?, drill a pilot hole the size of the centerpoint of your bit to depth first then bore your with your Forstner bit. Bring the tool down slowly into the work, get that tool in its mark, if there's run-out your part will reflect that by wiggling a bit. When you assert pressure on the tool and engage cutting give steady pressure to form a nice continuous chip until heat builds up and release pressure to break the chip and repeat. I gottta go eat. Hope this helps. There many tricks up my sleeve as I have done a lot of precision work on machines 80-100 years old. Just ask.

This is excellent advice. Thank you.

 

[R. Stratenstein]

The center drill funnel diameter needs to be slightly bigger than the finish drill in order for the drill bit to bore a hole very close to it's size.

By "center drill" you're talking about a pilot hole, right? Doesn't make sense that the pilot hole would be larger diameter than the finish hole size.

The pilot hole should ideally be slightly smaller than the centering point on the Forstner or bradpoint bit, to offer a path of least resistance, while steering the bit directly into the center of the pilot hole. If the pilot hole is larger than the Forstner/bradpoint's centering point, there is more potential for wandering in the larger hole.

 

[Scrapperz]

This is excellent advice. Thank you.

Your Welcome. I'm glad you understood what I tried to put into words. Its much easier to show you face to face what principals I have in mind. If you don't just ask more questions. Have fun, learn and take saftey precautions whenever working with potential projectiles.

By "center drill" you're talking about a pilot hole, right? Doesn't make sense that the pilot hole would be larger diameter than the finish hole size.

The pilot hole should ideally be slightly smaller than the centering point on the Forstner or bradpoint bit, to offer a path of least resistance, while steering the bit directly into the center of the pilot hole. If the pilot hole is larger than the Forstner/bradpoint's centering point, there is more potential for wandering in the larger hole.

Sorry for confusing you,
I was talking about a drill in that statement not a Forster. The rest of my post is pointed toward his Forster (which is not a drill). I gave him more info than he needed true, only to try to give more insight into how tools used in a drill press respond to pressure and guidance from the operator.

In case you see two of the same quotes this one's from my "MaxiPad": "A drill that doesn't get a good start into hard metal will surely drift off course, much like a persons life. Always use a center drill first, then drill like there's no tomorrow." Quote by Scrapperz

 

[piece of ash]

Would a new chuck be considered?

If so... I can tell from the photo that is MORSE TAPER size 2... otherwise known as MT-2 ( I was a machinist in the 1800's).

1/2" Jacobs chuck with shaft is $50 on amazon. No 3 jaw chuck will ever be perfect... but a new Jacobs would likely get you down to a few thou of runout. And all the other tips about tightening, cleaning, etc... are all very correct.

 

[gashford]

Would a new chuck be considered?

If so... I can tell from the photo that is MORSE TAPER size 2... otherwise known as MT-2 ( I was a machinist in the 1800's).

1/2" Jacobs chuck with shaft is $50 on amazon. No 3 jaw chuck will ever be perfect... but a new Jacobs would likely get you down to a few thou of runout. And all the other tips about tightening, cleaning, etc... are all very correct.

Absolutely! Once I manage to have some spare time where it's ok to create some noise I'll get the current chuck off, cleaned out and inspected. If it needs a new chuck then that's what I'll do.

A week ago today, our second child came into this world. We are new members of the "2 under 2" club. There is not a lot of project time at the moment! I'll get there though.

Thanks for your input and I'll update the thread once I get that chuck off.

Cheers,
Graham

 

[Scrapperz]

If so... I can tell from the photo that is MORSE TAPER size 2... otherwise known as MT-2 ( I was a machinist in the 1800's).

Whoa how old are you?

 

[gashford]

Hey All - I thought I'd post something to let you know how it everything turned out.

I tried to use a hammer to "fix" the runout but it didn't budge. I tried it again, only using a bit more braun and ... yep still nothing.

In the end I decided it was more trouble than it was worth. I sold it for a $20 loss on kijiji here ... not bad considering I put in full disclosure of the issues (return spring was also broken). I consider the whole thing an inexpensive lesson.

So, if anyone knows of a nice no-frills 14" press that can be had for a couple hundred bucks here in canada, I'm all ears

Cheers,
Graham

 

[jxrobi]

selling same drill press

I'm hoping someone can give me some advice. I have an interested party wanting to buy my drill press - same as pictured in the original post.
How much should I ask? Mine is only differing by manufacturing date (1990/12) and hasn't seen much use in the past 15 years.
Thanks for any help!