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I'm looking for opinions on whether this is a risky way to implement a powered drill press table. Could this potentially damage my drill press?
https://www.youtube.com/watch?v=QauDNhbn2EU
If people have well reasoned arguments on why it could hurt my drill press, I will drop this line of development. But if the community feels it is safe, it could be a rather cool way to power my drill press table.
Thanks,
Rick
It clearly works, but kind of fiddly. Sufficient counterweight and sheave makes more sense to me. I'd extend a notched bar and quite heavy weight to accommodate varied setups. If it works on Tony Foale's Bridgeport pattern mill. . .
Not knowing the design of your drill press I can’t forecast the effect of your idea. However, I see some considerations. You are reversing the thrust of the Z axis. Are the spindle bearings suitable for this change? Normally, I grip the collar around the column to lift the table up. You have created a bending moment that is now putting stress on both the table collar and the column. How will this affect wear of these two parts?
Very good points that I had not considered. It makes sense that the bearings were not designed for a downward force.Quote:
Originally Posted by Saltfever
The center of gravity of the empty table should be close to that center hole so this would be the ideal lifting point with respect to bending forces. However, it is a terrible place to lift because it is right in the middle of the action when subsequently drilling. Place a heavy vise on the table puts even more weight near the center of gravity.
I've started to think about keeping the jack screw idea but not driven by the drill press. Although it adds complexity, a pinion gear that let me turn this screw from a drive shaft under the table would be cool. I could turn the drive shaft with my battery powered drill.
I like lifting the table near its center of gravity but the mechanism must be out of the way. It could swing out as needed under the table if not too much hassle. Maybe it could stay there. Clearly, thrust bearings would be good.
More comments from others plus think time will refine this.
Thanks!
Rick
Main problems with Vee-thread, combinations of diameter and pitch won't be very rapid lifting action, and Vee's have little tolerance for dirt and chips. I'm still a hold-out for ACME, which translate torque to movement quickly compared to a multi-start Vee.
Most round column drill presses use a rack and pinion. Bottom edge of rack is mitered, it rides in a chamfered ring encircling the column. Below that ring is another to take thrust. All it takes is a small handle, spins a worm/ pinion combination to climb or descend the rack. And when you let go it remains in that position, but table can still rotate about the column.
A couple Martin or Browning gears, matching rack, aluminum billet housing and a couple oil-lite bushings, and two stubs of thick wall pipe; if I insisted on mechanical positioning.
Aforementioned notched lever, stripper bolt, some chain and and a slug of rod stock for weight. Far simpler and equally effective.
How about a dedicated winding motor; provided 12v DC, attach a auto window or power seat motor. Substantial torque, controllable [single speed] RPM, hypoid-geared, reversible; need I continue?
Agree about the CG but . . . There is friction between the collar and the column. That friction is multiplied by the moment. Again, don't know the quality of your drill press and the amount of friction. Love your creativity. :-)
I don't know what brand of drill press you have but if it's a moris tapper it might pull the chuck off the qwill! I have rather large bench model drill press and it has a #3 moris tapper and I have had it come off a couple times,just saying!
Wouldn't THAT surprise an operator. Right before the table lands on his toes, formerly resting comfortably on the machines foot.Quote:
Originally Posted by skibo
Interesting, but my motor is forward only and I don't think it would be worth the change for me. That would keep that center hole centered, so that part is good.
Hi Rick;Quote:
Originally Posted by rgsparber
I'm thinking this the first idea of yours that I don't like. Here are a few concerns:
- Morse tapers and even a Jacobs taper really don't like to be pulled. In the lifting mode you are pulling on those tapers, potentially breaking one loose and spinning it. This could lead to taper damage.
- What happens if you forget to lossen the table Clamp? In any sort of solution for table lift that involves a motor I'd really would like to see some sort of slip clutch or other over load mechnism.
- I suspect you will have greater reliability by adding a lift aid that is close to the clamping collar as possible. My great fear is snagging something and snapping a casting.
- If something where to break loose you run the risk of the table dropping a considerable distance and that is a big safety issue in my mind. Getting hit by dropping cast iron is never fun even if only a few inches.
One approach that might work would be a chain or belt drive with a separate motor to drive the collar up and down. Yes a bit of fabrication work but it should eliminate any potential damage to the taper that might happen. If you need to maintain table rotation then it gets a bit more involved because you need another collar to lift the table collar.
In any event my big concern is pulling the arbors out. Having had this happen with sanding drums and other tooling I can say it is more excitement than you will want to have in the shop.
This is my biggest concern friction fit Morse tapers, with no draw bar, really don't like operations that pull on the taper. I've had them pull out using drum sanding attachments and even had a case where the drill bit cork screwed into the material being drilled and dislodged the taper. A cork screwed drill bit generally results in in a bit of frustration but a sanding drum and arbor is extremely dangerous flying around the room and results in dodging the free drum and nasty words from ones mouth.Quote:
Originally Posted by skibo
To put it another way I'm not real comfortable with this approach.
I have I believe a very similar if not identical drill press to yours. Mine is a Craftsman built by King-Seeley Tool Co. I have not yet done it but am going to make the counterweight assembly for mine. I would be worried about something binding up and breaking the table casting using the threaded rod arrangement. With the age of these machines you'd probably NEVER find a replacement table.
My 15" Rockwell Delta variable speed drill press did not come with the optional raising and lowering rack for the table. I've decided to make an electric mechanism to accomplish this using an 18" Linear Actuator, DC Power Supply, and Actuator Controller, all affordably available on eBay. I'll post it here when designed and built.
Rick,
I think that this is an ingenious idea, but as others have pointed out there are serious issues. The reverse load on the tapers probably being the killer. My first reaction was a worry about the offset load causing jamming at the column but your video shows no sign of that happening. Your lift force is close to the CG.
I faced the same problem with an elderly Craftsman without a rack and pinion lift. I have largely, though not totally, fixed this with a counterweight.
Attachment 29290 Attachment 29291 Attachment 29292 Click images for full size versions.
This system could easily be powered, the top pulley could be replaced by a motor driven drum. The motor could be quite small because the counter weight reduces the lifting force necessary. The counter weight will not be at the CG so there will still be some jamming moments on the column. These moments will vary with load on the table. Of course if you make such an arrangement, with one finger on the "lift/lower" button you have a free hand to assist the lift and better balance those moments.
I can say from my experience that just the static counter weight has made lifting the table so much easier. Prior to adding that I used to avoid moving the table by using blocks under the work piece to get the height necessary. Now I move the table instead.
The high speed sensitive drill that I recently made needed the motor balancing, the table was fixed and so there was no weight variation to cater for and I put effort into balancing the moments.
Attachment 29293
As described in http://www.homemadetools.net/forum/d...947#post129563 and the movie at
https://youtu.be/2B79TP1v8-8
Hi Rick,Quote:
Originally Posted by rgsparber
Only problem I can see is that if you forget to unlock the table before the move you end up with a crabbed table and if the long screwed rod is strong enough you will crack the table close to the column. Even with the table unlocked I suspect it might be a risk- noy sure I would do it.
My counterweight set up works well and I may end up just making a few minor improvements to it. But it is always healthy to take a fresh look at stuff.Quote:
Originally Posted by Toolmaker51
Thanks,
Rick
I do have a length of ACME threaded rod. I played with it on the end of a small electric screwdriver and it does appear to work. It would work a lot better if my ACME nut was in a pinion gear so the screwdriver was horizontal.Quote:
Originally Posted by Toolmaker51
My RF-30 mill/drill has the arrangement you describe and it works well enough. Once I changed to CNC, I have not needed to move the head much.
I forgot that I have a window motor from a car. That shows a lot of promise! It has a lot of torque so would add a mechanical fuse to the linkage to protect the drill press.
Thanks,
Rick
The collar to column interface is not an issue when the table is raised at its center of gravity. But when lifted at the column, friction can be a killer. As an experiment, I cleaned the column and applied some way oil. The table moves easier and quieter when lifted at the column yet the clamp still works fine. It is interesting how way oil can do that.Quote:
Originally Posted by Saltfever
Thanks,
Rick
I agree. If the chuck was on there with a taper, this would not work. Mine is on there with a clamping collar that prevents the chuck from coming off.Quote:
Originally Posted by skibo
Rick
Lots of good insights. If I was using a taper, that would be a deal killer. If I do pursue using the spindle, I would have to add a mechanical fuse to protect the rest of the drill press. However, I would also need some way to prevent the table going into freefall. This could be a counterweight system which would also deload the spindle.Quote:
Originally Posted by wizard69
My existing counterweight arrangement is well balanced when the table is empty and good enough when the vise is on it. I help it along by either lifting up the front of the table or pulling on the chain going to the weight. No need for a motor. My chain is just stainless steel ball chain and of unknown strength. It has held for a few years and shows no sign of weakening. But it is a little hard to grab. One option would be to go with a thick nylon rope and make new pulleys.
Thanks,
Rick
Tony,Quote:
Originally Posted by tonyfoale
Having a nice action on the lifting mechanism certainly depends on connecting to the center of gravity. One idea I had was to add extension arms out the back of the table and put weights on the ends. This would shift the COG to the column where a counterweight mechanism would connect.
Thanks,
Rick
Rick,Quote:
Originally Posted by rgsparber
You can see from the pic of mine that I have a table out the back side as well so it brings the CG closer to the column than yours. Putting weights out the back combined with a heavier counterweight would seem to be a great idea. If you watched the video on my sensitive drill press you will see how much difference you can get when the system is balanced correctly, taking the moments into account.
The problem then is only if you move the table after putting a heavy vice and workpiece on the table. Set the table when it is empty and you can get a near optimum system.
I wish that it was practical to counterbalance the knee on my Bridgeport. I have added pneumatic springs which help considerably but their force varies with knee position and so are far from optimized but still a huge help.
http://www.homemadetools.net/forum/k...5951#post82823
Now I just need some form of assist for my own aging knees, too many falls from motorcycles have done them no good at all.
Quote:
Originally Posted by rgsparber
the idea is great but would not work for you most of the time because, most of the time you need to move the table is when you have something clamped to the table and have to adjust the hight between working with small bits then using larger bits on the same hole or after you clamp something to it and find out the travel is just not long enough or short enough
Rick,
I enjoyed your posting but had to laugh. How hard is it to lift or lower a drill press table? The most important feature is to ensure the up-down table movement stays centered with the drill press table center hole. Often, I did not noticed the slight off-shift on my drill press table after adjusting the table height and ultimately drilled a hole in the table. I think the up and down alignment position is more important than making it easier to lift the table.
Regards, Paul
I have lost a chuck before when using a sanding drum or a spade wood bit, my drill press is a large bench model about 40 years old and perfect condition! I would be aiming for a small 110 or a 12 volt reversible gear drive motor to run the table up or down, like maybe a gear drive 12 volt! They sell these on E-bay,cheap and most are reversible!
skibo
Paul,Quote:
Originally Posted by Paul Jones
Lowering is no problem but I can assure you that some tables can be a pain to lift. On the other hand I find aligning the centre hole to be a trivial exercise.
re ACME nut; there have been occasions 'we' bored one gear and turned another to assemble a different drive. A matching pair of miters would be simplest of all.Quote:
Originally Posted by rgsparber
I don't have a conventional round column drill. I use one at work once in a while, my go-to for chamfering/ de-burring, and table is never at convenient height. 50's era but very sound, and the column is clean.
Much harder to slide the table up holding the table than handling it adjacent to the clamp. Center of gravity might be middle of table; but real issue is close fit of clamp and column, ~.002 max. Holding table imparts angularity [likely in 2 planes] on the cylindrical fit; binding is unavoidable. I find swiveling it helps normalize the disparate axis but doesn't last very long.
I'd think propelling the table via a screw in the spindle would do same thing.
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Thanks tonyfoale! We've added your Drill Press Lift System to our Drilling and Drill Presses category,
as well as to your builder page: tonyfoale's Homemade Tools. Your receipt:
<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-drill-press-lift-system"> <img src="/uploads/222858/homemade-drill-press-lift-system.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-drill-press-lift-system">Drill Press Lift System</a> <span> by <a href="http://www.homemadetools.net/builder/tonyfoale">tonyfoale</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/pulley'>pulley</a>, <a href='http://www.homemadetools.net/tag/drill-press'>drill press</a>, <a href='http://www.homemadetools.net/tag/lifting'>lifting</a> </div> </div> </div> </div>
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dkutzner,Quote:
Originally Posted by dkutzner
You are right. Most of the time I am raising the table to be near the end of a drill. So having the table's center hole aligned with the spindle won't work. What if the table was rotated to one side? Then the chuck mounted threaded rod would not pass through the work area. I would have to eyeball my clearance from a greater distance but maybe it isn't that critical.
This is not the ideal location table position because the center of gravity of the table would not be aligned with the lift point. But it is closer than lifting at the column.
Thanks,
Rick
Paul,Quote:
Originally Posted by Paul Jones
My drill press table is a bit heavy and is a bad lift. Toss on my vise and it is hard to lift the table with one hand while keeping the other on the column lock. As Tony said, aligning the table is the easy part. It is especially easy if there is a locking collar under the table.
Although I have tagged my table once and it was right at the side of that center hole, I do try to drill in a vise or put down some MDF before clamping the part.
Thanks,
Rick
Rick,
My mistake and comments. I didn't look too closely at your photos and video. I assumed your drill press table like mine already had a side mounted up-down crank handle with a gear engaging a linear cog gear along the back similar to my drill press table. Manually moving the drill press table up without the crank would be difficult because my drill press table weighs more than 40 pounds.
The problem I have with my old drill press table is the up-down geared crank handle system can easily move the center hole point very slightly off-center when using a clamped vise or other part that has been already clamped down. I readjust the center position and it is difficult to notice the very slight offset movement until the drill clips the side of the drill press table center hole. Drilling the table original center hole a little larger is probably a simple solution but I like the smaller hole for drilling small parts without the vise.
Regards,
Paul
