Electric (not air) drill?

[jharmon]

Has anybody ever mounted an electric drill on the 'bot instead of an air drill? I haven't seen anything with regard to going that way.

I am just now getting my BT48 going and was surprised to learn the damaging affects of drilling with the spindle. I had planned to do a lot of drilling but neglected to buy an air drill and don't even have the 36SCFM capacity air compressor to support one in any event.

Seems like a light enough/mountable model would be viable for bolting to the primary Z with the appropriate bracket. Am I missing something?

Jim

[blackhawk]

Jim - Just curious about the "damaging effects" that you encountered drilling with the spindle. What were they?

[tparr]

Can you expand more on the damaging affects of drilling with a spindle?

[gpari]

Spindle bearings don't like drilling.

[jharmon]

Hi Brad,

Nothing I encountered myself but I learned that the bearings are primarily designed for side loading. That occasional hole drilling is not a problem but a lot of boring should be done with a drill.

Given that I'm surprised there isn't more on this topic and the electric drill option.

Now I'm worried about smoking the bearings on my new spindle.

Jim

[br928]

Jim - I have been using an electric drill on my bot since I bought it. In fact, I bought the bot to modify it just to drill holes in steel panels. This is how it earns it keep.

For the woodworking applications I started with a PC router and recently upgraded to a spindle on the second Z. When I went to a spindle I had to modify the handle of the drill to keep both the drill and spindle Z's inboard. The trigger and speed control were removed. I used the drill 'out of the box' for years when I had room for the handle.

The Milwaukee drill is perfectly set up for this application. Just area behind the chuck is set up to accept a handle. A bracket made of 1" PVC was made to hold the drill at this location. An added bonus is the bits can be changed by hand with this chuck. (Model 0302-20)

This set up has drilled thousands of holes over the last 5 years.


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[Gary Campbell]

Jim....
What size holes and in what material are you drilling? If you are not drilling metal, you should be able to accomplish most drilling operations with a carefully thought out toolpath. Even tho not recommended, there are many out there drilling with spindles in wood products or plastic. Of course, you may then own the warrantee on the bearings, but all things considered, it may be the less expensive option.

I am working on a 5 bit head that I may use a variation of an electric drill motor head to turn. The air motors with enough power seem to use way more air than I have compressor for. Here's a pic of the head:

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Gary

[blackhawk]

I think Stan has the right idea. I just looked at the price of Shopbot's air drill, $1750 bucks, wow! I figure you can wear out about 35 Milwaukee electric drills for that kind of money.

[jharmon]

Hi Stan,

Awesome. Just what I was thinking about. Thanks for the pics!

I see yours is with a second Z. Do you believe I can get away with this kind of idea without going to a second Z? Is 5.6 pounds light enough to mount to the Z plate in front of the spindle? I guess for $130. I could try it and find out...

This solution looks ideal - what is the virtue of the air drill I wonder?

Jim

[jharmon]

Hi Gary,

That 5 bit head looks very impressive. Nice job. This is actually more what I had envisaged. A single head thing like this with a fairly small but powerful motor driving it.

I only want to drill into wood - maybe some plastics. My concern stems from the number of holes I want to drill.

For example, I am interested in Ari's great mosaic creating program and this thing can spit out a file with 60,000 holes or more! Now, these holes are small (1/4" or less) and maybe only 1/4" deep at most with the most likely medium being melamine or something similar.

Jim

[jharmon]

Hi Brad,

I agree! I am on the Amazon site now


A little quick math says I won't quite get 35 Milwaukee drills for $1750. (even with tax and shipping to the West) but your point is well taken! That couldn't be more straight forward.

Jim

[br928]

Good luck trying to wear out one of these Milwaukees. I have replaced the bearings once in 5 years and I am brutal on it.

The air drills turn at a much higher RPM than the Milwaukee's 850 RPM max. The Milwaukee can draw 8 Amps and can generate much more torque than an air drill.

Which drill you need really depends on the application. Speed vs torque.

I would use my spindle to drill a mosaic in relatively soft material if I needed over 10K RPM and could get a clean cut.

The harder the material was, the more concerned I would be for the spindle. Drilling is 100% thrust load and spindles don't like that, but will tolerate some.

[Gary Campbell]

Jim...
If I were going to make an add on for your machine to drill files with hole numbers like you mention above I dont think I would use a drill motor like Stan shows above. To get your drilling time as low as possible you dont want to use standard drill bits. You might want to look into high helix plunge end mills. Based on what you state above, here is how I would do it:

For the power head I would use an inline die grinder with a 1/4" collet chuck (20K+ RPM)
Mounting would be a SB air drill bracket or shopmade clone that has an adapter that clamps to the nose of the grinder like Stans drill clamp above.

For drilling, especially in melamine, I would use an Onsud or Belin Super O flute (single) They are available in 1/4" shank

If you use a tandem setup on a single Z, you can toolpath using the PRS drill postP and use a fast Z speed. Couple that with a safe (drill) Z of .25" your per hole time would be very low for the shallow holes you describe.

There are already utilities shipped with the control software that will allow you to set the X, Y and Z offsets for your tool using variables in the my_variables file. You will have to decide whether to manually lower the drill to below the spindle bit or simply remove the bit from the spindle when running a drilling file.

Depending on how complicated you want to make it, you can use the controlled output (#5) that normally plunges and energizes the drill to switch the grinder(drill) powerhead. You would need a TTL relay board, a relay for the 110v motor and a little wiring to complete this.

If you do decide to use a lower RPM solution, try the carbide boring bits, you will have cleaner holes and much longer life vs a standard drill bit.
Hope this helps. Post pics when done!
Gary

[br928]

The Milwaukee 0201-20 has a keyless 3/8" chuck and 2500 RPM speed.

This might be better in some applications than the one I use.

[jharmon]

All great info. Thank you very much!

Gary - thanks for spec'ing a solution for me. Using a die grinder never entered my mind (didn't even know what a die grinder was) but then when I checked it out I see what you mean. Kind of like a Dremel on 'roids.

Although it may be arguable that these bearings are any better designed for thrust load than the spindle is I like it. I'm all over it - die grinder is on the way.

Now, this TTL relay board, etc. - is that stuff you get from ShopBot tools? It would be especially sweet to get it all hooked in to #5!

I'll post a pic when I get it done.

Thanks again
Jim

[3imoh]

Hi Jim-

I posted a link to a relay board you can use under suppliers/vendors(http://www.winford.com/products/rly104.php).

You would still need a 110v relay for the drill, but this will get you switched power out of the SB for 4 output switches.

Edited: Looks like the relay contacts are rated at 15amps, so depending on the drill, you could probably switch it directly. My preference would still be to keep all the relays on the board switching low amperage, and have one of them control your higher powered relay. One extra moving part, but it would make repair/replacement easier on the relay that is going to get the workout.

thanks,
Howie

[khaos]

ShopBot has a relay board thats not on the price list yet. Just call for details.

[ed_lang]

I have the ShopBot relay board and control my cyclone dust collector, vacuum motors and have it push my start button for me.

Real nice setup.

[Gary Campbell]

Jim...
ShopBot is the most reliable source for the CORRECT ttl board, but if you can find what specs you need I assume that there are many sources out there. I looked on the Winford site that Howie refers to above and you have 5,12 & 24V power options and depending on what low voltage power overhead you have available in your control box, one of these may work.

Even tho many of these boards have relays that can handle the amperage of the items we want to switch, I prefer to keep all of my "add on" wiring in the control box low voltage. I did add an additional 24V power supply that powers the ttl board, my drill and a few relays. I made a separate box that has a divider between the low voltage and line voltage connections on the relays in an attempt to "make the NEC happy". All the low voltage wires come in on one side and the other side has outlets that are switched by the relays. I have both 220V and 110V outlets that are fed by SO/SJ cords.

Most of the relays and sockets were bought by the dozen off eBay.
Hope this helps, Gary

[ed_lang]

Gary,

I bet folks would love to see a open box picture if you would share it.

I would at least.

[dana_swift]

The shopbot uses standard TTL ("transistor-to-transistor logic") levels, which may not mean much, but it is the most common digital interface. Any TTL solid state relay rated for the load should work just fine. You can find them new on http://www.digikey.com or go the ebay route.

Ed I like the idea of having the shopbot push the start button for you, that really gets annoying after a while. I will probably borrow that idea from you!

D

[Gary Campbell]

Ed...
Sure thing, but it will be a while. We are working up north at Ocean Reef for a few more weeks. Most shop time is dash in and out. To see this box I need to stand on my head in a pile of dust and look thru the wiring maze.
Gary

[Gary Campbell]

Ed...
Due to a few additions coming with the addition of a dual Z, I had to upgrade my power supply. This meant a larger enclosure so I took a few pics before installing it. I also added the ability to have either spindle activate the dust collection with automatic or manual operation switched from the gantry control panel.

Here is the outside view:

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And one of the inside:

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Gary

[ed_lang]

Thanks! Looks great!