Cole Drill revisited
Every so often I come across references to this tool. For the sort of work I do it would make a lot of sense. However the chances of me running across such a thing in the UK are miniscule so given the simple nature of the thing I've decided to have a bash at making my own. I think I've gathered most of the information I need from looking at photos but I'd like to sense check a few things with those who may have used the real thing.
What I'd like to know:-
How long is the hollow bolt that the drill spindle runs thru?
Is there a thrust bearing used? And if so where is it, top or bottom of
the hollow bolt?
So far I am planning to use a M16x1.5mm bolt drilled to take the spindle and an off the shelf thrust bearing at the bottom of the bolt running against a flange on the drill spindle.
For the ratchet drive best I can come up with at the moment is to use a 1/2" drive ratchet from a socket set which kind of leads to the logic of turning the drill spindle from an extension bar from a 1/2" set.
If I can find some cast iron chunks I could use this for the body of the drill head and base but failing that there should be no problem using cut offs of mild steel, say 3"X2" ?
Once again all information, ideas and suggestions gratefully received. If I get started with this I promise to take photos!
The hollow bolt is about two inches long. The spindle is stepped, with a smaller diameter through the hollow bolt, and the thrust bearing goes between the bottom of the hollow bolt and the wider portion of the spindle. I am guessing that this would be stronger than a flange. It's a simple ball thrust bearing similar to those found in scissor jacks and the like.
If you need, I can take pictures and get proper dimensions later.
Here's a quick shot of the spindle and screw assembly. The spindle below the bearing is 1 inch diameter, and about 1/2 inch where it goes through the screw.
The ratchet is a simple spring-loaded plunger in the handle. One way only, no reverse. The ratchet wheel is threaded to the top of the spindle with a little shoulder, so when you turn the handle it simply tightens down on the shoulder.[IMG][/IMG]
Thanks Bruto, that's brilliant. Exactly the information I required. Very kind of you to take the trouble to do that.
On a different tack, Vermont is one of the few states I've visited. My brother-in-law had a scholarship at Harvard back in the late eighties. My wife and I paid a brief visit one February which co-incided with one of the heaviest snowfalls that area had seen for a long time. Nevertheless we managed to get about OK and Vermont we decided was our favourite as it was most like home.
Thanks for your help once again.
I purchased one from the US through Ebay, shipping was over $100 but it was
well worth it they are a great tool.
Previous to this purchase I intended to make one and have good diagrams
with measurments etc.
If you would like copies of these send your postal address via a personal message and I will mail them to you.
RW, that is very kind of you. My address is on it's way.
Sorry guys this has been a long time coming but I have nearly finished this project.
As promised some work in progress photos.
First though I have to acknowledge a huge debt of gratitude to Ross Walker who posts on here as RW. Ross very kindly sent from Oz a set of measured drawings, photos and card templates of his own Cole drill. Really beyond the call of duty and I can't say how much I appreciated the gesture.
At the end of the day design and construction was dictated by the materials at hand.
First problem was the bolt. I managed to find at a local motor factors a 1" UNF x 3”
I drilled and reamed a ˝” hole through this and purchased a suitable thrust washer from an online bearing supplier.
Raking around in my spares department I unearthed a casting from an old DIY type pillar drill stand. This was cut up to produce the brackets for the base and head of the drill. The castings were bored for 1.25” round bar and looking around the workshop I realised that the guide rails for my woodworking table saw were 1.25”. I had a pile of extension bars for the saw that only see occasional service so these would do very well for the drill pillar, with the added bonus that they can be screwed together to give an extension if required.
The cast base and head were not large enough to fasten the working parts of the drill to so two sleeves were cut from 60x60mm steel box section and slipped over the castings and fastened in place. The bottom sleeve is fixed with 4 M8 caphead screws running into tapped holes in the cast iron base. For the top sleeve a 1”+ clearance hole was bored at one end and concentric with this I welded on a 1”UNF nut.
To lock the head to the pillar and minimize racking under pressure I filed semi-lunar notches to the profile of the pillar on the steel sleeve. Then a steel stirrup was bolted to the sleeve. An M8 capscrew running in a nut welded to the apex of the stirrup pulls the sleeve back hard against the pillar at a fixed 90degrees. This works well.
The base plate is locked with an M12 capscrew running through a tapped boss in the casting and pushes a steel pad against the pillar.
When I received Ross’s drawings and saw how simple the original crank handle and ratchet I fully intended to copy it. However in raking around my scrap pile I unearthed a Stanley woodworking brace with a non repairable chuck. The ratchet from the brace was slipped over a spigot turned on the top end of the new drill spindle and cross-pinned in place. The rest of the ratchet housing then fits over this and is bolted in place, this time with an M6 capscrew. A bit of butchery of the brace crank, M12 threads cut on the ends of the two resulting pieces and the whole lot joined together with an extension nut and locked with two full nuts.
The Jacobs chuck is again from the scrap pile and is locked to the main spindle with a couple of grub screws bearing on the chucks plain spindle.
The whole job is yet to be painted but I have tried it out and have to say it works really well. I can fully understand the rave reviews that Coles drills receive on this site.
Nice. I especially like the ratchet adaptation.
Very nice. Been looking for a cole for a ehile, may follow your lead and build my own.
Also, I see that I'm not the only one who uses the tablesaw as an assembly bench. In my case I have it on rollers so it slides under a work bench, which means it is often the only 'table' that's clear (for at least three seconds after sliding it out anyway)