I just want to thank everyone who commented - I took the suggestions and was able to make big improvements! The drill could drive a Forstner bit, but only at it's maximum torque speed of 2800RPM (not ideal but not a dealbreaker for softwood). I rearranged the drive in line with the drill, and stabilized the bearings so as not to distort them. Thanks RU-vid brain trust, I owe you!
Assuming there's nothing wrong with the drill, your lever arrangement may be causing the bit to rub on the back side of the hole it's drilling, as you are pushing it down. As in, (as others have said here) you need to get that down force closer to where the drill is operating. As in the bit isn't traveling vertically after you start pushing it down, but at a small angle. What you've built may seem stiff and rigid, but may not be up to resisting the bending moment when there's so much distance between where you are pushing down and the drill bit. Also the lever arrangement isn't giving you any mechanical advantage. As it's configured it's just a linkage. Ideally you want some multiplication of the force you are applying so that the tool isn't a chore to use. The tradeoff is the lever needs a long throw to get the same plunge depth.
Hi, you can try by changing the force point of the pressing system. Set it near the drill, not near the steel rods. Have I make you understand what I am trying to say? Sorry for my horrible English.
The problem is the lack of torque on the drill. Just compare the size of Ryobi's motor with the drill motor. In addition, Ryobi has a pulley system for speed variation and better use of torque. You will never get the same performance from a hand drill. But you did a great job and I like the care you put into your work. Also try moving the upper clamping point of the lever to a position more in line with the drilling axis. The applied force will be closer to where is needed. As if you were holding the drill in your hand.
I made this type, but I ended up using a drill as a belt drive so I can adjust speeds with a belt pulley system. It's only 5 speeds, but I'm able to make drill run at full power so as to not lose torque.
I looked closely at your experiment with the Ryobi drill press. If you notice the Ryobi crank is designed to convert rotational torque to linear force easily. The center of rotation is almost at the center of the drill shaft, thus 135# of force. I do not know the angles of your handles, but I assumed 30 degrees for your top handle. So you had 53# from design. My engineering calculations shows that 106# goes down to the pivot point and 91# alone the x axis. Try moving the unpainted back (lower bolt) toward the drill. I think this may introduce some binding on the linear sliders. I do like your design. Did the drill work with the forstner bit by itself?
notice the one you are basing it off of has the trigger on lock. what was the thought behind the screw controlling the trigger? hope that doesn't sound snotty or critical just sharing a thought that may help. Also it looks like the one you based it on has a higher quality drill. Dewalt has different drills that meet different requirements and different budgets.
A) The distance between the axis of the drill and the linear slide rails will reduce the downward force of the handle that lowers the mechanism. The design goal of the offset is to give greater throat "clearance." If someone wants to drill the center of a 2 foot disk, then the drill needs (slightly more than) 1 foot of clearance from the rail to the center of the drill. However, in placing the drill farther from the rail, it acts as a multiplier to decrease the force applied at the handle. Any gains you achieve by making a big sturdy handle are offset by that same distance from the rail (pivot point) to the drill axis. To get leverage, you want the distance from the drill to the pivot point to be short compared to the distance from the handle (where you push down with your hand) and the pivot point. To get more force from a (hammer, baseball bat, gold club), one holds it at the end of the handle. To get more control, one holds it closer to the head (A 100 pound man can lift a 600 pound barrel if the man has a bar and the man is 8 feet from the pivot point and the barrel is 4 inches from the pivot point.) B) That said, drilling is NOT about downward force. The downward force being applied is loading down the drill and causing it to stall. The goal is not to create a hammer that drives a drill bit through wood. Drilling or sawing is about severing material and removing it from the cut space. What a drill bit requires is sufficient speed and torque at the outer cutting edge to sever fibers and remove material so that the cutting edge can continue to cut. Wider drill bits require more torque to maintain correct speed farther from the center of the drill. C0) Out of the lineup of the Dewalt corded drills this does seem to be an entry level model, most suited to small holes in drywall for nails and screws. One thing we did not see demonstrated in the video was how well the drill can drill(cut) without the mechanism of the drill guide. C1) Test the same bits drilling into a board freehand (no stand) C2) Test the same bits drilling in the press stand but trigger the switch manually instead of with the thumb screw. C3) Test the same bits drilling with the battery drill freehand. C4) Test the same bits drilling in the press stand with the battery drill but trigger the switch manually instead of with the thumb screw. C5) Clamp your workpiece to the table. Drill a pilot hole at 1/8" and then step up your drill bits at 1/8" increments D) Sharpen the drill bits E) Use a socket in your drill to tighten a nut and bolt at max. Use a torque wrench set at lowest setting and increase until the bolt loosens. This can give a ballpark figure for the drill's torque **** **** **** Torque **** **** "Drill Clutch Torque Experiment with Stupid Mistake" ColfaxMath "Torque vs Speed, Angular and Linear Velocities of a Drill" ColfaxMath "DIY dynamometer (friction torque meter) using 3D printer" Tube Underdeveloped "What is Torque? - Fastening Theory Part 1" Flexible Assembly Systems Inc **** **** **** Levers & Mechanical Advantage **** **** "Physics - Simple Machines - The Lever Lab" Neural Vortex **** **** **** Clearing Material **** **** "The physics of bandsaw resawing" Matthias Wandel "How to Sharpen an Auger Bit For a Brace and Bits" Wood By Wright **** **** **** **** **** "3D Router, when a CNC machine is overkill" Paoson Woodworking **** **** **** **** **** "Dewalt DWE1014 Review - Corded Drill with Keyed Chuck" ProductReviewsOnline **** **** **** **** ****
Take the drill out of your fixture. Plug it in and with a forstner bit drill into the wood. If it drills no problem, then your fixture trigger hardware is incomplete. If your drill did not run the bit through the wood? Check for voltage switch wrong position. If still no good, put a known good drill in your fixture. Hope this helps.
The Dewalt drill uses a simple variable frequency drive (VFD). The speed drops but so does the power: the torque is not constant. The goal is to start slow for accuracy, then pull the trigger all the way. For this application and woodworking, the easiest way is to bypass this drive and run at full throttle.
Your drill does not have closed loop speed control. That is why it slows down under load. Normally when a person holds this drill they squeeze the trigger harder to compensate for slowing. I suggest trying it with the trigger all the way in. Second thing is the downforce. The brown wood struts between your white handle and the part of the drill press that moves down are not straight up and down. Thus some of your hand force goes into trying to push the drill slide to the right and is wasted. I suggest mounting the lower pivot of the brown wood struts right in line with the center of the drill chuck, one on each side.
I believe you lose most of the force because of the two support pieces that hold the press handle. if you move the lower side of them closer to the drill I believe you will get much more force.
Perhaps a lower speed drill motor. The variable speed trigger slows the bit down but it doesnt torque. I think you are expecting too much from a small. I do like the concept.
Like your idea for your drill press. Different design than JSK boubou. There is also another video of a similar drill press by a gentleman Gokmen Altuntas that you might find interesting. Both of these drill presses have a different handle setup than yours. Their handles are mounted to the "pillar"on the back side not to the front. I believe this gives them more of a mechanical advantage than yours does. the link to Gokmen's video is ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-AzOCDoW_tSI.html. hope this helps.
1. Take the drill out and try to use it free style. If it works then it has enough power. 2. Your plugged into an extension cord/power strip. What gauge is the cord and how long is it? Any extension cord is going to reduce power on a drill due to voltage sag (just google it. Explanation is a long one.) 3. Make sure your drill is coaxial to the plunge axis. Even being off by a few degrees will add a torsion to the drill and reduce applied power. 4. Yea that a dull drill bit. Sharpen it. 5. Your lever is currently a 1 to 1. Move the main pivot as far away from you as you can and move the tierod pivot point further back. Ratio = handle to tierod pivot distance / tirod pivot to main pivot distance. Your drill press is gonna be close to 6:1 (12" handle diameter / 2" pinion gear). 6. Make sure your clamping fixture on the drill isn't pinching so hard you have distorted the guide bearing on the drill.
I'm sorry your testing procedure makes it look like your trying to make the problem what you want it to be instead of what it actually is. Testing means push it till it breaks. you look like your holding back where it matters.
