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Indexing drill press gauge - ball screw or?

The Dude

Hot Rolled
Joined
Oct 19, 2010
Location
Portland, OR
I need to make a single-axis indexing drill press gauge for positioning 2x4's for holes to be drilled. The total length of the indexing will need to be from about 1" to 80" (i.e. total travel length). Just doing some initial research on ball screws, they are available on McMaster Carr (not that I'd necessarily purchase from there) for about $1500-2K for the screw, nut, wipers and supports. That's within budget.

The initial setup for this will just be to provide a stop. The nut will travel to a programmed distance, stop, the operator will position the end of the 2x4 against the nut (with some type of stop mounted to it, that travels through some type of guide), manually drill the hole, tap a foot pedal to index, and repeat until the part is done (anywhere from 1-3 holes).

The main goal is to eliminate the use of templates which result in poor hole location quality and longer setup (there are over 50 templates). A PLC with a touchscreen will select the program (I'm good on all of that).

Three questions:

1. I assume there has to be some type of linear rail/guild that has a bearing that moves with the nut to keep the ball screw from vibrating? Seems like that distance would be way too long for a nut to travel with little support.

2. Aside from the ball screw, is there any other technology that might be better? I was thinking maybe cog belt drive, but a bit concerned about the integrity. Occasionally, and operator might "bash" the end of the 2x4 against the stop.

3. Is there anyone that makes an off-the-shelf unit for this type of operation? It has to be "programmable" (pull up a program # with per-programmed stops). The only close thing I've found is the Tigerstop but their smallest unit is still kind of "big" and I'm not sure it can do the incremental step programming (which can occur at increments that aren't equal to each other).

Thanks for any input.
The Dude
 
How much does a tiger stop cost ?


Oops, I see you looked at them.

Did you call them about maybe a smaller one ?
 
How much does a tiger stop cost ?


Oops, I see you looked at them.

Did you call them about maybe a smaller one ?

Yes, it was a few months back (on & off project) but there were some functionality issues as well, and I can make the design more compact.

Thanks,
The Dude
 
DiamondSure diamond drill bits are specifically designed for use on very hard materials.A bit increases as the bit diameter becomes larger, the drill rpm speed must be reduced on larger bits.
 
tigerstop seems like the first choice, I can say they withstand abuse of a shop well. there is an increment button on the saw gear itself, "incr" 5.25 start start start and stop moves 5.25 inches plus kerf (drill so kerf would be zero), if you type 5.25 start then it moves 5.25 inches from blade. Tigerstop interlock to machines is not as industrial as the stop itself, prosumer wiring and switches shoehorned into machine. that lasted 5 years or so, stop is 14 years and still going.

belt or rack and pinion will be cheaper and have potential for faster material positioning than a ball screw. You say compact size matters, then pinch wheels might work better than a stop.
 
…. Not familiar with that.

Thanks,
The Dude

printers, copiers and atm's use them. a single drive wheel with pressure onto a cam follower, maybe simplest drive system? Voortman_V630_14.jpg This is bigger version with a 'knurrled' steel drive wheel for beams.
I wouldn't worry about bashing a belt driven stop, I and others have more than bashed our tigerstop (which was pre their metal working line) and worst is it errors out on its own, requesting a re home routine.
 
If you're set on a screw, I would look at an acme screw instead of a ballscrew. You can buy anti-backlash (spring-loaded) nuts and as long as the stiff direction is away from the operator you'll never have backlash. This should be cheaper and more tolerant of dirt and misalignment than a ballscrew.

The easiest solution is probably a single-axis belt drive actuator. You can buy one with 2m of stroke off the shelf and all you'll need to do is bolt up your stepper motor, or you can even buy them with motors and absolute encoders.

A bigger question is why drill the holes manually. If you're going through the trouble of having a PLC and HMI to select programs, why rely on the operator to push the 2x4 up against the stop and pull the drill handle?
 
printers, copiers and atm's use them. a single drive wheel with pressure onto a cam follower, maybe simplest drive system? View attachment 249401 This is bigger version with a 'knurrled' steel drive wheel for beams.
I wouldn't worry about bashing a belt driven stop, I and others have more than bashed our tigerstop (which was pre their metal working line) and worst is it errors out on its own, requesting a re home routine.

Very nice.
Much like a IIRC Peddinghaus beam line.

Add a mitering saw, and you've got yourself a truss making saw.

By using this above pictured scheme, operators just load the saw, no banging
hard against a stop. The rollers feed the material in.
 
I don't want to overcomplicate things... Oh wait, yes I do. If you have floor space, wouldn't this be better done on a CNC router? That way you can have holes that aren't all in line, and could fixture up all the parts for a kit at once.

Once you automate X, you're gonna want to automate Z, then you're gonna want to automate Y for that one off-axis part, then you'll want to automate tool changes, then you'll wonder why you have the operator at all, then you're at a CNC router.

A cnc router has value if you need to sell it again. A shop built automated fixture is worth the ebay price of the parts.
 
I don't want to overcomplicate things... Oh wait, yes I do. If you have floor space, wouldn't this be better done on a CNC router?

Actually, we "went down that road" and it dead-ended. Tech-wise, it would be fine. Work-flow (which many people ignore), it was horrible. I won't get into details but I'm working on a CNC router for them to be used as a drill for small "block" parts cut from lumber. The main issue is that these parts are done a few at a time through out the day with gaps of time in-between (a person doing another operation performs this as a side job). That keeps the inventory down. To do it on the router would have required a larger router, "batching" of the whole-day operation, gather-up all the parts, run the parts, having to mark them (not currently needed), put them on a cart, have someone pick them on the "as needed" basis when the assembly line was ready. If a mistake was made (wrong part, missing part), then you'd have to interrrupt the router while it was doing the small parts (and the bed would be setup differently). Long story short, it was worth looking at but would just create other nightmares. In this method, you can grab a part, select the program, drill it and put it on the cart in about the time that would have required all of the handling in the other method. Not to brag (okay, maybe I am!), but my main focus is on "efficient & effective work flow" (not just the process labor) and that would have killed this. You can call it lean if you want, but you don't have to always call it that if you just want to do work more effectively.

Thanks for the suggestion, and please don't take this as a knock as I had the same idea (for a while)!

The Dude
 
To do it on the router would have required a larger router, "batching" of the whole-day operation, gather-up all the parts, run the parts, having to mark them (not currently needed), put them on a cart, have someone pick them on the "as needed" basis when the assembly line was ready. If a mistake was made (wrong part, missing part), then you'd have to interrrupt the router while it was doing the small parts (and the bed would be setup differently). Long story short, it was worth looking at but would just create other nightmares. In this method, you can grab a part, select the program, drill it and put it on the cart in about the time that would have required all of the handling in the other method.

I admit to some confusion here. If your process is potentially successful on a custom machine that has a programmable stop and a drill spindle, and all you have to do is call in the program, why would a router have to be batch driven? Couldn't you use it exactly as you'd use your "stop machine", but with more options for other work when the need called?

At worst, a smaller router with a two-step stop (so you can do the entire 8ft length needed with a cheaper machine) should be feasible.
 
I admit to some confusion here. If your process is potentially successful on a custom machine that has a programmable stop and a drill spindle, and all you have to do is call in the program, why would a router have to be batch driven? Couldn't you use it exactly as you'd use your "stop machine", but with more options for other work when the need called?

At worst, a smaller router with a two-step stop (so you can do the entire 8ft length needed with a cheaper machine) should be feasible.

I'll answer your question if you can convince me that this is worth "dragging on". Otherwise, and I apologize, but I have to work!
 
Just in case anyone looks at this, there is an update. I decided to give the Tiger Stop one more try. The first time I went to their website, the "product selection" came back with "sorry, got nothing". This time, it came back with their simplest stop and it looks fine. Funny thing, technology can be both great and "cumbersome". After I selected the product, I went through the online configuration process, very complicated. They ended up calling and got things straightened out. Looks like about $6K for a programmable drill fence up to 6' long. Very reasonable. Thanks to those who suggested it (and other advice), it made me think enough about it to go look one more time.

The Dude
 








 
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