Noisey Power Pro Headstock

[hfmann]

Bill, Chad, David, RFGuy, and all,

It sure is nice to have such helpful experts as yourselves here to graciously share and help us without that knowledge, or even feeling in way over our heads. Thank you!

Update: ordered parts on the phone. Pam said they all were in stock and should ship Monday. So now I wait while I fiddle with the quill and previously posted rubbing noises.

hal

[RFGuy]

I did a quick search and found at least two postings online that seem to indicate similar problems of setscrews coming loose on the Nova DVR lathe as well. Of course, we don't know if this is due to vibration from the turning or whether it is due to the DVR motor itself as I mentioned in my last post. One of them tried red loctite and said it still came loose and the other one claimed to have success using blue loctite (counter-intuitive, I know).

https://www.aawforum.org/community/inde ... r-xp.8076/

https://www.inspirepoint.com/woodturnin ... 48556-.htm

[hfmann]

Today's update:

Took the quill out and it sure looked like it was going to be bent when I got it all apart. Almost ordered a single bearing one from ShopsmithRepair.com but the existing two bearing one wasn't bent. Looked really good when fully apart. I'm thinking about getting a single bearing one just in case things go bad later. Has anybody returned to the older single bearing version?

Solved the rubbing noise on the upper belt. I was anxious to get a feel for the eccentric when everything is put together and I'm into belt balancing next week. Loosed the eccentric bolt and turned it a little. Rubbing noise GONE! We'll see what happens when all reassembled .

All for now.

hal

[JPG]

A word regarding 'hysteresis'.

It IS essentially backlash.

Adding 'hysteresis' aggravates the overshooting problem.

It also aggravates an under damped loop.

But by over damping, response time is lengthened.

Lengthening response time creates greater speed variation.

i.e. many parameters determine design decisions.

Add in variable loading at different speeds due to variable SPTs being driven and a very complex design goal is created.

[hfmann]

oh no.

Got parts in yesterday. Installed the new pulley and belt. But one of the instructions on the video call for loosening the outer motor mount screws before adjusting tension. Darn it. One of the allen screws head stripped and I can't get the screw loosened. The 5/32 wrench fits but turns inside the head when pressure is applied. Tried 3 in 1 oil, different 5/32 wrenches to no avail. I could force the motor in enough to get the fine thread motor mount screws in ok. But without getting that outer motor mount loose before adjusting everything tension makes me very nervous.

HELP! Any ideas on how to get that screw loosened?

hal

[DLB]

I apologize for answering your question with a question, but... Let's back up a little bit. Which screws did you loosen and/or remove to get the belt and pulley out? Did you completely remove the motor from the headstock, or just tilt it? Can you post a picture of the exact screws in question? There are, IIRC, three motor mount screws on each side that are countersunk into the headstock and go into an aluminum motor mount. IIRC these are the fine thread screws. They are #50 on the headstock drawing, to my surprise they are metric (per the same drawing). Separate from those are two "Tension Locking" button head screws on each side. These are #102 in the drawing. Note - there are a quantity of six of those #102 screws, four are "Tension Locking" and two are "Belt Alignment" screws. Also to my surprise, metric.

My first suggestion is let's see which screws you removed during disassembly and analyze whether the stuck screw actually needs to come loose. (If it is a Tension Locking screw it needs to come loose to perform the adjustment.) My second suggestion is to try a GOOD 4 mm tool. I'm going to go confirm this on my own PowerPro, but one might think if these are in fact metric screws then we are using 5/32 inch tools because it is "close enough," 5/32 inches is ~ 3.969 mm. You are only going to get one shot with the 4mm tool in the already damaged screw, which is why I'm saying use a good tool. Something from an impact set would probably be my choice for this, they are generally much harder than Allen wrenches.

Good luck. If it was me I'd delay at least a few hours and see what other members have to add. And don't worry, there are more ways to get the screw out if the 4mm doesn't work.

- David

[hfmann]

Thanks David,

You're helping me calm down.

No - didn't remove the motor. Tilted instead. I removed 4 of the 6 fine thread screws (#50) and slightly loosened the top (in DP mode).

I uploaded a small picture (much smaller than posting criteria) but it doesn't show.

After getting the new pulley on and locked in place with LocTite Blue'd setscrew, I put the new belt on by tilting. then slightly loosened 2 button bolts (#102) that go into outer motor mount (part #107) on one side, then attempted same on the other side. One of the button (#102 bolts loosened), the other stripped. As you look at the machine in DP position, it is the bottom bolt whose head stripped. I believe these four screws are the "tension adjustment" ones you mention.

As to the 4mm wrench, don't have one. Measured everything I've got with digital caliber. closest was 3.95mm, and that did work.

Standing by......

Start thinking about the next problem. In an effort to take tension off the problem screw, I tried adjusting the other tensioning screws (#102, and 103). They are all out of whack now.

thanks,

hal

[DLB]

I dropped the motor cover on mine and confirmed that a 4mm is a much better fit in these screws than a 5/32". It has much less rotational free play and feels like the proper fit to me. Today I learned that there are some metric screws in a Shopsmith PowerPro.

Getting your alignment screws back to a starting point once you get this screw out won't be hard.

- David

[hfmann]

Ok - thanks David,

Just placed an order for 4mm wrench to pickup today locally. Fingers crossed.

(btw - just switched preferences from Shopsmith board style to ProSilver and I think that'll let post pictures. Here's the picture I couldn't post before.

outer motor mount screw head -ss forum.jpg (65.59 KiB) Viewed 1530 times

hal

[RFGuy]

Looking at your picture, it is a pan head style screw and it looks like you have good access. IF the interior hex is stripped, why not use a pair of Vise Grips pliers to clamp down on the exterior of the screw and turn it? It will take a few times of clamping and releasing the Vise Grips until you get it loose enough to turn by hand, but based on the picture it looks doable to me. Alternative would be to use screw extractors, but that would be more trouble than the Vise Grips I would think. Of course, if you get it out, you will need to get a replacement screw to replace it.