Thoughts and ? re: spindle extender

Another solution

Dominic Greco in Richboro PA

>Mike,

From an engineering standpoint, you'd be putting that piece of 1 1/2" dia. x 8" long (approx.) tubing under a little too much load to be considered safe. You'd either bend it, or have it break at a most inopportune time. :>)

Why not fabricate a longer vacuum bell from 4" SCH 40 PVC pipe? The larger cross section will help with the stability issue. You can make the length of pipe 6" or 8" and still have clearance room from the headstock. You can cut the pipe, and mount it to a piece of 3/4" MDF on a face plate. Seal with some mouse pad material, and away you go. Thats what I did and it works just fine.

See ya around,

Dominic

Re: Thoughts and ? re: spindle extender

John Lucas

>I'm going to try to go and see the people at bestwoodtools in the next few weeks. I would love to see their shop and they only live about 40 or 50 miles from me. I'll pass on your thoughts.

I don't think I would worry about the bearings. It's probably not any more torque than you would apply by putting a 12 to 14 inch long piece for hollow turning. We did 12" pieces when I took a one day class from Frank Sudol.

I'd like the setscrew also. I would be a little concerned with boring the hole for vacuum. It could weaken it but you don't need a hole bigger than 1/4" which shouldn't cause much of a problem on a 1 1/4 " shaft.

Re: Another solution

Mike Schwing from Maryland

>Thanks Dom. The issue is removing the spindle extender each time I want to use the vac chuck. With a longer vac drum I'd still have to the same.

Plus, there's no tubing involved. I use a neat piece of equipment from Oneway - a rotary vacuum adapter for the tail end of the headstock. Its really nice. Check it out, it should appeal to your engineering head...

http://www.oneway.on.ca/Oneway/rotary_adaptor.htm

John, thanks. My thoughts were, too, that a 3/16-1/4" hole wouldn't impact the strength of that beefy extender enough to worry. Please let me know what they say.

Re: Thoughts and ? re: spindle extender

Jerry Whitaker

>Mike,

I got my spindle extender from Powermatic when I bought my lathe and it already has a hole all the way through the center....looks to be 1/2 inch and it has set screws on it for reverse turning.

thanks, and an interesting call

Mike Schwing from Maryland

>Well that is interesting. After your note, I called the PM techies because I had a question about the lathe's braking schedule, and asked them about the spindle extender. They had to go and retrieve one, and said "nope, no hole in the middle, but we're discussing adding that right now due to your call"

BTW, I was REALLY dissatisfied with their answer about the electronic brake. The stop time is programmed to 5 seconds. I asked if we could reprogram mine down a bit. They said it might be dangerous to bring a 100 pound blank to a stop in 1 or 2 sec, and it might trip the inverter, so I'd have to unplug, wait, and plug it back in. So I said "ok, lets try 4 seconds and if that happens, we can put it back". The response? "we can, but it'll void your warranty."

I find that "warranty void" response HIGHLY dissatisfactory. Seems like VERY lousy customer service to me. They didn't indicate at all that there was a danger to the machine.

When my warranty is up I'm going to take them up on it.

Re: thanks, and an interesting call

Gary Evans

>Hi Mike,

I'm just curious about the braking time on your lathe. 5 seconds doesn't seem excessive, particularly with large blanks. Just curious as to why you would want to speed up the braking.

Remember, life's too short to get in too big of a hurry! 8^]

GE

Re: thanks, and an interesting call

Mike Schwing from Maryland

>Gary, if there's something in life that can be done, I want to know about it. I want to know what can be done, how, and what the consequences are. I knew that the braking was done electronically, and knowing that, had a good question about why 5 seconds, why not 1? why not 2? Why not 10? Life's too short? You're damned right it is, I don't want to spend it waiting for my spindle to stop. I get 80 years here if I'm lucky. Pretty soon those 5 seconds add up to an hour!

Of course 5 is not a long time, but when I find myself frequently putting my hand on the spindle to stop it more quickly, I want to know if it can be done by the machine and how that might be accomplished.

Re: thanks, and an interesting call

Jerry Whitaker

>Mike, I went to check my spindle extender again and measured the hole that goes all the way through the center. I took the t-handle off my OneWay Stronghold chuck key and the top of that key fits perfectly into the hole in my extender and it measures 9/16 in. Also, it has two locking set screws 90 degrees apart. Guess I just got lucky.

I understand!

Greg W in NC

>your frustration! Since I do a lot more spindle work than I do bowl work, I wanted to also slow my ramp down time some, as well. It was stopping in about 6 to 7 seconds. That is frustrating since I stop my lathe frequently for various things (primarily pens), namely to sand horizontally for each grit. After reading one of my posts here about my frustration with my Oneway taking longer to stop, Kevin Clay with Oneway emailed me, told me to call him at home and he'd personally walk me through reprogramming it. I did just that, and he very graciously walked me through the process, and I've been a happy camper ever since!!! Now THAT is customer service!!!! Now, if I want, I can reprogram it back to where it was. I also have two settings for a faster and a slower ramping time.

Re: thanks, and an interesting call

Peter Teubel

>Mike wrote:

"The stop time is programmed to 5 seconds. I asked if we could reprogram mine down a bit. They said it might be dangerous to bring a 100 pound blank to a stop in 1 or 2 sec, and it might trip the inverter, so I'd have to unplug, wait, and plug it back in. So I said "ok, lets try 4 seconds and if that happens, we can put it back". The response? "we can, but it'll void your warranty." "

===================================

I have a Delta VFD for my pattern makers lathe and its fully programmable. Came with a very through manual. Since I have a braking resister installed, I have mine set to 1.5 sec full torque ramp down and 2.5 sec ramp up. Needless to say, I use set screws in the chucks and drawbars with the faceplates.

If I am not mistaken, the PM 3520 also has a Delta controller (at least the one I saw). You should be able to get the manual and reprogram anything you want.

Re: thanks, and an interesting call

John Lucas

>Mike

In this society of sue everyone I don't blame them for not wanting to change it. It can be changed I altered the one I had on my old Nova and a bowl came loose with shorter brake time. Fortunatly it hit the tool rest and stopped but it could have been dangerous.

VFD can be programmed to do an amazing amount of things but can you imagine all the problems a company would have when all the people start playing with the programs. It would be mighty easy to screw things up.

I agree I would love to be able to go in and change all the parameters to fit my needs but but many of the changes you can do also affect other parameters such as motor torque and feedback for continuous torque.

The braking and slow start frustrate me when I'm spindle turning but I've decided to just relax and turn.

Re: thanks, and an interesting call

Gary Bills in NC

>I think 5 sec. is a good compromise. I also have had bowls start to come off because of the quick braking. Also, I've had the brake disingage because of a heavy blank on the lathe (100 lbs. or more). That's when you find out just how much time the brake is saving you. I think at less than 5 sec. there would be more bowls coming off and the brake disengaging more often. That might be why the company made that coment.

brake time

TDaniel

>My VB-36 has a toggle switch tht allows me to choose between fast braking/starting or slow braking/starting (ramp up/ ramp down). On very large pieces the brake action is bypassed to prevent overload of the braking circuit. The manufacturers have to evaluate all possible loads and program for the optimum. There are no magnetic brakes (caliper type) involved here, just electronic. A really large piece on my lathe may take minutes, not seconds, to stop.

Re: brake time

Mike Schwing from Maryland

>I figured this topic would be interesting enough to elicit good conversation, and am thankful for the responses.

My qualms aren't with safety, I understand the issues involved, and I've had a faceplate start to unscrew itself while braking a very large (for me 100 pounds is very large) blank.

So I now use setscrews wherever possible.

I was just displeased with the nice conversation I was having with the service rep about how things could be done, and then suddenly shut down when he realized I was about to ask for the codes, with the infamous "warranty void" issue.

In fact, the warranty voiding issue makes sense from their standpoint, the way it was thrust on me seemed like avoiding an issue, or avoiding work on their part.

Re: Thoughts and ? re: spindle extender

Lyn J. Mangiameli

>Interesting how the same needs surface, repeatedly, yet it can be so slow to get a response. I called for these very things a couple of years ago, and has hoped that BWT or Steve Houston (Woodtradesman) would follow through with the modifications. They seem so easy to integrate into the initial production, but are such a hassle to deal with later. I also wish they would put a similar hole in spindle adapters. Obviously the hole would not have to be very big at all, and from extensive prior discussions on spindle strength on rec.crafts.woodturning, it appears that they would have essentially no meaninful effect on strength if they are anywhere reasonably sized.

I run the same vacuum configuration as you and really do prefer accessories like the BWT Texas Drives, and the Wood'N Things buffing adapters that allow me to avoid the Morse Taper and/or allow for easy vacuum connection. I haven't pulled my vacuum adapter off the headstock for over a year now, but do still experience the same occasional frustrations with extender length that you do. So I greatly hope your renewal of the pleas shall be effective this time.

PM3520 VFD manual *LINK*

Rick R, So Cal

>Mike,

Do you know the VFD manual is available on-line? I haven't found the need to mess with the settings, but it's good to know that you can if you want to.

Rick


PM3520 VFD manual