Drill Press evolution continues / 8" DP with idler pulley

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m1kemex

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In a separate thread I mentioned that I own a 13" Taiwan made drill press that has always been faithful to me, but at about 40-45Kg, it's too much hassle to carry around. Therefore, I purchased a smaller one (8") some time ago to take with me when I go to places. It's far from great, but it's only 16 Kg, so it's far more practical when I don't foresee anything complicated.

Still, I've been thinking for a while on ways to improve it and the first thing that came to mind was to add an idler pulley to get a larger range of speeds. To my surprise, after a bit of research on the topic, I've discovered that there are actually small drill presses with idler pulleys already. This one goes by several names (the first I found is sold by Shopmax) but a more generic DP13 "9 speed" shows many distributors in Google:
drldprbmrbd13_alt_2_v1.jpg

Don't know where it's made, but I think it comes from India, which explains the "adventurous" nature of the proposition. I call it that way because, if you look carefully at the pictures, you'll notice that the entire head (and many other parts) is made of stamped steel. It weights 12 Kg according to specifications, which is a good 4-5 less than a similar sized one with cast iron parts.

I wonder where I can get a set pulleys readily made...
 
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I built a contraption to run a third pulley on a benchtop drill press I had. It was fun, but I’m not picking up any hints from my memory that it worked very well.

While I don’t know your personal kit, a pulley set would be a fine project for a lathe. Perhaps you might find the pullies you need, hidden in a few slugs of aluminum.
 
jwmay said:
I built a contraption to run a third pulley on a benchtop drill press I had. It was fun, but I’m not picking up any hints from my memory that it worked very well.

While I don’t know your personal kit, a pulley set would be a fine project for a lathe. Perhaps you might find the pullies you need, hidden in a few slugs of aluminum.
Click to expand...
I could do that but I'm a bit of practical minded: don't really see the point of making what I could get readily made. But if I can't find the pulleys I will certainly make them.

Machining the parts is not the problem; the problem is doing the calculations for the sizes and final speed range. And specially the geometry of the pivoting shaft for the idler puller, as both the spindle and the idler get tension from the motor. Of course, it's not rocket science, but I could save myself the hassle.

I've already determined that that I can't simply leave the spindle pulley and just add the idler: the speeds would be all wrong. Instead, the spindle pulley should become the idler and I need a new spindle one. If I want a higher top speed, the upper grooves of the spindle pulley should be sightly smaller than those of the idler. Otherwise the upper size of the cone should be the same and become larger and larger, to get the slower speed range. Since this models have 5 groves per pulley, I think I could do both without issues.

I think it's worth having a decent small drill press you can take with you. The problem is that they cut a lot of corners with the 8" models.

P. S. I've been researching on the topic and I think I missed the one I truly wanted: Harbor Freight used to distribute a 10" version with Morse taper, 12 speeds and rack operated table. It wasn't that heavy, I think it was like 20 Kg or so, just 3-4 Kg more than mine. The base and the table were horrible (stamped steel) but that's relatively easy to fix compared to nearly rebuilding the head.
 
We're sure living weird times! I've found no drill press spares on Aliexpress, but I found them, of all places, in France!

10" rack bracket with pinion:

10" rack:

10" MT2 spindle:

I've even found a five step pulley that may be adequate:

But seems like I'm cursed because they don't ship outside France/Belgium...

P. S. Why nobody sells replacement tables? With the "arc of shame" so common, I'd imagine there would be a lot of demand...
 
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