spindle

[garyr6]

I hear that drilling with your bot's spindle is not a good idea. Can some one explain the reason. I assume it has something to do with the bearing.....

[dlcw]

I drill all the time with mine. I run 6000 RPM at 30ips Z rate. I use boring bits made for boring machines. No regular drills or router bits. The boring bits I get from Toolstoday.com use a 10mm collet.

[donclifton]

I think you mean 30 IPM not 30 ips.
Don Clifton

[beacon14]

I hear that drilling with your bot's spindle is not a good idea. Can some one explain the reason. I assume it has something to do with the bearing.

If you are referring to the HSD spindles this is a myth that has been de-bunked several times on this forum. With other spindles I suggest you contact the manufacturer and ask them, they will know better than anyone here.

[Brady Watson]

David - didn't you have to replace the bearings your HSD after only a year and a half of service (http://www.talkshopbot.com/forum/showthread.php?t=1715)? Isn't it true that even you use an air drill or Porter Cable for drilling shelf pin holes in production?

I stand by what I have always said: Occasional drilling is fine. If you are in production, invest in a drill. Drills drill. Routers route. The bearings of each are setup for two entirely different types of loads. Research and understand this if you care about your spindle.

These lower end HSDs aren't as robust as you would think, so I would treat it as nicely as I could in order to get as much mileage out of it before it required replacement. There's not much cost difference between rebuilding and replacing the entire spindle & most spindle repair houses won't even work on these lower end HSDs, (including HSD!!!). If you do wind up rebuilding one, it will never sound as smooth & quiet as a new spindle.


I emailed HSD, here is the response...

-----
Good morning Robert,

I’m sorry I can not help on your inquiry, HSD USA do not offer a rebuild program for the type of spindle mounted on your ShopBot machine, the reason we do not offer to repair the collets spindles is not price effective, the cost of the bearing plus labor time for the repair will amount to the same price for a new spindle.

Thank for contacting HSD best regards

Luca.

HSD USA
----


I don't know why some are hell bent on proving you can drill with a spindle. (of course you can - but don't expect it to last) The bearings are not setup for production drilling - period! The salesman who said it was OK to drill at the IWF already knew these are throw away spindles...Why wouldn't he tell you what you wanted to hear?

It's YOUR spindle - do what you want with it.

-B

[dlcw]

Thanks Don. You are right, 30ipm. And, I only drill plywood; no other material.

[beacon14]

You don't miss or forget much Brady, I have to admit. But I did not have to have that spindle re-built after 1.5 years, I elected to as a pre-emptive measure, and even after the re-builder practically had to pry the housing apart, then tried to tell me they couldn't get it back together to run within published specs, then managed to get it working again, it still ran another year or so before I ended up replacing it - however - that spindle had not been used for drilling! I had been using the ShopBot air drill since my earliest drilling days. I ended up wearing out the air drill from drilling, not the spindle, and replacing it with a PC for several reasons, mainly because there isn't room for two spindles on my PRT carriage, nor in my wallet to buy two spindles at the same time.

I've since worn out one PC router and had it rebuilt, it spends 98% of it's running time drilling holes. I think the bottom line is - if you push your tools hard they will wear out sooner than if you don't, and if you use light duty tools they will need to be replaced more frequently than if you use heavier duty/beefier tools, regardless of whether you are drilling, routing, or both.

I agree that for a production oriented, repetitive task it's best to use a tool that is designed for that task. However, in most cases in the real world, some level of compromise is called for.

Personally I prefer to rout my 5mm holes instead of drilling them, for two reasons. Using a down-spiral bit and a spiral-plunge toolpath gives me perfectly clean holes even in brittle melamine (something I never achieved with a brad-point bit in the air-drill); and I have the ability to tweak the hole diameter by .001", so even as the bit wears I can maintain a nice sliding fit of my shelf supports in the 5mm holes.

Anyway, I do not mean to be argumentative in any way, just trying to clarify my position and prior experiences.

[Brady Watson]

No problem David. Hopefully what I have written here will shed some light on why drilling with a spindle is frowned upon.

Few things are more disappointing or catastrophic than wiping the bearings out of your spindle. This usually happens either in the dead of winter when work is slow or in the middle of a large job. It's really no fun at all and a significant expense for most shops to absorb in order to get their machine working again. I'd like to 'debunk' the 'myths' regarding drilling with spindles, regardless of brand. I would hate for readers to get the impression that it is suddenly OK to do production drilling with their spindle because of hearsay at a trade show. I would hardly count that as a factual way of getting to the bottom of things.

If we look at the whole 'drilling with your spindle' topic from a mechanical/engineering perspective, all of these spindles have bearings that favor radial loads, or side to side loads that would be applied by routing. If you take apart one of these spindles, you will see that the bearings are nothing more than single row caged ball bearings - not unlike most bearings you have seen on other motors, skateboards and any other application that incurs radial loads. The contact of the balls to the races is mostly in the 9 and 3 o'clock positions if you look at your spindle as it is mounted on the CNC. They favor forces in the X & Y directions, and have limited capacity to deal with loads in the Z direction - since the apex of the ball, (12 & 6 o'clock) is unsupported by a race. There is nothing but dead air @ 12 & 6! - Be sure to understand this!

Excessive thrust loads can gall the balls and races, because they get distorted from their normal path, if the force applied is great enough to displace the balls in the races. Shock loads are a perfect example of how drilling just one hole at a fast enough speed with a non-center cutting bit can apply enough force to shock those bearings. You want to avoid shock loads and excessive thrust loads on these spindles, or you WILL gall the bearings and really kill the life span of your spindle.

A drill on the other hand, has bearings which favor axial/thrust loads, or loads in the Z direction. The bearings are typically some type of angular contact configuration which can deal with these types of loads because the apex of the ball or tapered roller, is fully supported by a bearing race. No spindles that I am aware of that have been sold on a ShopBot have these types of bearings. They ALL use radial ball bearings that have a limited capacity to withstand thrust loads.

The type of bearing installed in the spindle answers the question whether or not it is suited for production drilling. On a ShopBot, this is a resounding 'NO'. The bearings just are not made for drilling. Occasional drilling, with reduced speed AND and CENTER CUTTING tool or drill is usually fine as long as you avoid shock loads and fast speeds that can apply a lot of force in the Z direction. I think that drilling is fine if you use discretion and know the FACTS. Production drilling @ speed, puts too much shock load into the equation if you want to make money on your parts. This is where an air drill, electric drill or 110v router makes sense on a 2nd Z.


-B

[beacon14]

"I think that drilling is fine..."

There! He said it! I think I'll just take your comment out of context and go with that.

Just kidding. Thanks for the detailed explanation, I'm sure this discussion will help a lot of people make informed decisions regarding their machines and machining strategies.

[Brady Watson]

"I think that drilling is fine..."

There! He said it! I think I'll just take your comment out of context and go with that.




LOL! :D

Hey...It's your spindle & your wallet. If you wanted to drill cinder blocks with it, it's your call :p

-B

[donclifton]

Well again your wrong. Routers and drills have radial bearings. They cost $10 to $25 dollars. Spindles have angular bearings which cost $250 to the sky's the limit. If spindles had radial bearing every one would be replacing them.
Thanks
Don Clifton

[curtiss]

I would suppose one could always "mark the holes" with a small bit on the spindle and then ......DRILL them out later with a DRILL.

[bleeth]

Technically you are correct regarding it not being recommended to drill with a spindle. However I have been drilling with my Columbo 5HP (This is far from an HSD 2.2) for 8 years. It has been used for regular cabinet production for the last 5 years plus with many batches being runs of 100 cabinets. It drills all line boring, hinge holes, and drawer slide holes in melamine, plywood, and plywood with laminate. I keep the plunge speed low (.5"/sec) but that isn't too slow to get the job done in a reasonable amount of time and peck drill with one pullout to a depth of a little under .5. The bits are made for plunging (.5mm compression bits from Centurian. Bearings are still perfect. No noise, no runout, no problems.
When it is running the back dado and cutout paths I don't ramp in, but just plunge it.
I've never needed to do a dimes worth of service to the spindle and do make sure it gets warmed up and cooled down.
The smoothness and lack of required service has, IMHO, made the up front investment well worth it.

[Brady Watson]

Well again your wrong.

The Colombo 5hp has two single row deep groove ball bearings in the nose. Pics here (http://www.talkshopbot.com/forum/showthread.php?t=1688) from someone who actually took one of these apart. When you take apart your spindle & post pics, then I will respect your opinion regarding this subject. Who knows, maybe your spindle has different bearings in it. I'd like to think that my track record has been good enough over the years to allow me to be wrong from time to time. If you are going to call me out on something, have the documentation or pics to back it up. I'm not going to sit back and watch inexperienced users ask questions and share in the Cool Aid sipping answers. Sorry! The new guy coulda been me from years gone by, and I don't want anyone to have hardship over bad information.

At the end of the day I could care less whether you drill rocks with your spindle. I truly do not care. What I do care about is the dissemination of bad information bred out of superstition, myth or hearsay, that gets read and ingested by new users...which I believe is what has happened here in this case of drilling with a spindle. Few ever got the facts, and the truth became something akin to whisper down the lane, with people believing whatever they want about the subject. Belief cannot trump facts.

Just to reiterate what I have been saying all along:


From PDS Colombo's site: http://www.pdscolombo.com/engineering_angle.php

High Speed Electric Spindles designed for routing applications are equipped with bearings capable of achieving high RPMs and enduring high radial loads (side cutting). When entering the work piece with these spindles it is important to keep the axial loads low in order to prolong bearing life.

When programming your work-piece, entry angles should be kept from 0º - 20º off the table. This will keep axial loading low and allow feed rates at 100%.

When the work piece design requires a steep entry angle, the feed rate should be reduced according to the chart. This will minimize axial force on the bearings.

Above all, avoid "crashes" of the spindle into the table, fixtures and work-piece.

Specially designed Electric Spindles for drilling or boring applications are also available.

If I am 'wrong' from here on out regarding this subject, then so be it. :rolleyes:

-B

[donclifton]

First off I'm far from new to the machinery and equipment world. I have rebuilt several spindles and with the exception of chinese spindle everyone had angular bearings not radial. The differents is that the balls are supported not only on one side like bearings in routers and drills but on two side. Sorry if I hit a sore spot but I think you should make sure you know what your talking about before giving advice. I have never taken apart a columbo but have HSD and many others. Why do you think it cost so much to replace spindle bearings as compared to router bearing. A spindle is just a 3ph motor and most have bearings that are easyier to change then a router motor.
Don clifton