Upgrading PRT alpha to PRS Gantry?

[harryball]

I know Ted is big on making bots upgradable and I'm wondering what it would take and if it would be worth while to upgrade my PRT Alpha (which has the newer table with the aluminum side rails) to a PRS style gantry.

And, once done would there be enough room to run 2 spindles on the 48x96 table?

I see the PRS alpha is offered beginning with the 60" x 96" version.

I like the new gantry and I want a second Z, I didn't want to invest more in this old style gantry if I can avoid it.

Ideas, advice, opinions?

RB

[Brady Watson]

Robert,
While the PRS gantry is stiffer that the PRT ones, you really won't gain much noticable performance if you switched, aside from the added durability of hardened rails.

No. There is not enough room on a 4' wide gantry to park an extra Z and still have enough room to use the entire 4' cutting area with one Z. This is why you must order a 5' wide tool if you want 2 Z axes.

-B

[harryball]

Thanks,

I kind of figured that's why they were 60" wide but now I know.

Excuse me while I ramble and think outloud, feel free to do the same :-)

The biggest reason the new gantry style is so attractive to me is the easier access to change bits. Getting down on one knee to change a bit wouldn't seem like such a big deal, but it's killing my lower back (which has it's own issues with a pound or two of steel). I've tried several ways to access the bit while standing but I just can't get the hang of it that way without bending over which causes more pain than dropping to one knee.

One project I'm running takes 4 bit changes and I dread running it now.

I suppose upgrading to the new gantry for any significant cost would not be worthwhile if it would exclude me from ever having a second Z. I suppose I could live with it for a nominal cost, but I doubt that's the case.

My other option, of course, is to purchase a new PRS Alpha and sell the PRT Alpha. Which would consume the funds I've accrued for a second Z which would at least elminate the bit changes for my main product. Conversely... outfitting the second Z on this bot only compounds the difficulties accessing the bits to change them and consumes funds for a newer bot.

hmmm... winning the lottery and buying all the bots I want seems the best option.

RB

[Brady Watson]

I made my own 'C7', which moves the tool to 24,12, which I find to be a perfect location for my long arms to change the bits. Trying to change bits from the short side of the table is awkward at best...

-B

[Towersonline]

Here is my solution: My wife bought me a rolling mechanics seat. It sits about 18 inches off the floor. I scoot all over the place with it. No more back ache from changing bits.

[geneb]

I use something similar. I've got an old roll-around office chair that I've removed the back from. It's got a gas cylinder in it for height adjustment and I've got it set so I can comfortably rest my elbows on the 'bot table while working on the spindle.

However, don't let that ruin your good excuse for getting the PRS upgrade.


(it's on my list too)
g.

[Brady Watson]

When I was in the sheet metal union, there was a saying: "If you're sitting down, you ain't working."


-B

[myxpykalix]

I have a "apple box" (a rectangle plywood box) that when i sit on it I am at eye level with the bit and it is comfortable to change the bit at that height. After i change bit I stay there till file starts so i can see where it goes and make sure there are no obstructions till the file starts. Then i just scoot it under the table and use the padded stool.

[sawkerf]

A little off topic, but am I missing something about bit changes on a PRT Alpha? I set my "home" @ 15x/5y/2z to facilitate all bit changes standing up. What's with having to get on a knee or sit on a stool? Are you guys running spindles? Just curious, Kip

[beacon14]

I use my collapsible camping stool. Since I'm rarely camping and using the 'bot at the same time it works out pretty well.

[Brady Watson]

I have no idea, Kip...I am wondering the same thing. Seems having a Bot has made some of these guys a little soft...Just kidding guys! I think it is just a matter of preference whether you stand or sit. Just be sure to put the lid down or you'll get in trouble.


-B

[knight_toolworks]

most of the time I don't need to know the exact hight of the it when I install it. if I need that I use my small adjustable square set it to the right measurement and put it against he bit and the tip on the nut. no need to bend over to change the bit.

[harryball]

I didn't mean to start a "sit, lean, stand" debate. :-)

I'm running a 4HP HSD spindle. Gantry is configured so the Y motor is facing the X=0 end of the table where I stand when changing bits. I have a bit change position at -4,18 which puts the spindle at a good location for me. I can remove the dust skirt and the bit without bending over or kneeling but when installing the new bit I find it easier to get it right (though not comfortable) to do so. I check the bit position, hold it in place and tighten the nut. This is all done with the spindle extended down slightly. If I raise it up it makes it even more difficult to get at up in the gantry. I find it very awkward to try and change the bit from the bedrails side of the table.

It's a concern for me is due to an issue with my back, otherwise it's not that big of a deal.

/RB

[richards]

Every time I change a cutter on my 3hp spindle, I remove the nut entirely. That allows me to blow the dust out of the nut and collet, seat the next cutter and reassemble everything in about two minutes. I've never had to kneel down or even lean over too much to do the job.

[ed_lang]

I change cutter like Mike does. Remove the nut and clean the collet and spindle shaft with air.

[harryball]

I also remove the entire nut/collet. I tried several times yesterday to reinstall it still standing... just awkward and I can't see the flutes on the bit which can move while I'm installing. I just prefer to SEE the flutes and make sure they are not in the collet or the bit is extended too far. If it had some kind of stop or notch or detent or something I suppose I could get use to it.

/RB

[ljdm]

Not sure if it would mess with the balance, how about locking collars - like used on drill bits to set depth, or used on 1/2" shafts? The collars meant for shafts are probably made more for long-term use, as far as balance, while the drill bit collars aren't used hours at a time. The shaft collars come in alot of sizes . Just a thought...