# advice please: lathe "kicking" with large bowl blank



## duncsuss (Aug 21, 2009)

I've got 4 large bowl blanks (I think they are ash), about 11" diameter by 7" bowl depth. These are the largest & heaviest pieces I've tried turning. It's the HF 12" x 33-3/8" lathe (THIS ONE).

Started the first one yesterday, using a screwed-on face plate and the live-center at the back end. The first time I turned on the lathe it jumped around a lot, so I trimmed it a bit and that improved a lot.

After getting it round using the lowest speed, I tried making it a bit faster -- result was very bad kicking and loud knocking sounds, so I quickly slowed it down again.

I'm wondering if there is something wrong with my lathe -- shouldn't I be able to speed it up a bit once the blank is actually round?

It's still within warranty, I can take it back for an exchange but there's no point if this is expected behavior.

Thanks!


----------



## txpaulie (Jul 21, 2010)

In my limited experience, I've found that round does not always mean balanced...:no:

Some blanks have more weight in certain areas...

When I find a imbalanced blank, I try to find a "happy speed"...

Kinda like yer old ford shaking at 57 mph, but smoothing out at 62...:yes:

On more than one occasion I've scrambled to move stuff off of the lathe bench before they hit the floor.

Sometimes, it's best to allow the wood to dry thoroughly, before turning.

The big guns will be along shortly to help(both of us:laughing.

Good luck!

p


----------



## duncsuss (Aug 21, 2009)

txpaulie said:


> Kinda like yer old ford shaking at 57 mph, but smoothing out at 62...


Thanks Paul -- I didn't have the nerve to take it any higher when it was already scaring me at speed 2 :laughing:


----------



## NCPaladin (Aug 7, 2010)

I don’t know if it will help but a couple of observations. First, your have brackets across the legs; I would add a plywood shelf and pile on about 4 bags of sand. Next, the lathe itself must be shy of 175 pounds since that is the shipping weight. Then, your low speed is 600 rpm and that is very fast for a bowl that size. 
Are there adjustable feet on the legs? If so the lathe needs to be leveled using the feet with a slightly out of balanced piece mounted up and running.
The 11” diameter is fine but the 7” deep adds a* lot* of weight. Even the Powermatic at our club would shake at that weight and speed. Also, even when round, the wood may not be in true balance due to differences in sap wood, heart wood, etc.
I doubt if it is your lathe but it possibly could be. I don’t know what speed you went to after you got it round but I would just stay at the lowest (600 rpm). It I had the blank on my lathe I would start at my lowest (200) and probably never go beyond the 600 range even when I felt it was balance. 
The higher speeds are typically for spindle (2” or so). At 2” there is about 6” coming around per rpm, for your 11” you have about 35” per rpm. Of course X your 600+ rpm = 350" per second. A huge difference.


----------



## duncsuss (Aug 21, 2009)

Thanks NCP ... very useful background information.

I only took it to speed setting #2 -- 750 rpm according to the spec sheet -- before immediately backing off to the lowest 600 rpm setting.

It does have leveling screws (which I adjusted when I assembled it), and I also have it sitting on a wheel base. Maybe I have to cement it into the floor for this kind of work.


----------



## Biscobob (Jul 25, 2011)

I don't turn a lot of bowls but I do turn some pretty large logs at times mounted to a face plate. One thing would be to recheck your screws, they can loosen up under the load of an unbalanced piece. Also try bringing your tailstock center into the piece while it is turning, it is easy to get it off center with the piece not rotating. Didn't think it was possible but I found out the hard way.

These are the two things I have noticed when things still shake and jump around even after it seems like they shouldn't. Far from an expert, just some of my experiences. One other thing, go over every nut and bolt on your lathe and work bench occasionally, surprising how things can loosen up on you.


----------



## firehawkmph (Apr 26, 2008)

Dunc,
600 rpms may be a bit fast for a blank that big, especially when its out of balance. When I rough out larger bowls, I may start below 400. You have to have patience with the heavy pieces. If the lathe starts doing the hootchie coo, it's going to fast. If you go to Bill Grumbine's site, he has a good video for roughing out bowls. It's worth a watch. He shows you an easy way to get the bowl shaped and in balance without taking a beating.
Mike Hawkins


----------



## duncsuss (Aug 21, 2009)

Thanks biscobob and firehawk ... I'll have to check the nuts and bolts.

Also I'll investigate whether it's possible to put an electronic speed control in line with the motor on this puppy -- the gearing is one of those mechanical thingummies (Reeve drive?) which I know will not preclude it, but the motor might not be externally controllable.


----------



## cuerodoc (Jan 27, 2012)

+1 on the shelf and then adding bags of sand.

I have one similar to that one- got it when I decided to venture into turning not using a shopsmith--that was the start of my descent into the vortex (startin to sound like admitting a problem--:no. Adding the sand really helped knock down the shake. Then after you hollow some out of the bowl i believe it'll spin more true. (And yes I do have more than one big boy toy---I like to have multiple projects going:yes
ALWAYS check the screws on the plate after some turning-- have had some suprises that I don't want to repeat.


----------



## DaveTTC (May 25, 2012)

+2 on shelf and bagged weight. I would use bags of cement as they weigh more. I would toss the adjustable feet, pack it level and screw / bolt it to the floor if that is an option. 

I have the same lathe and 9 other different ones. Mine goes by some Australian label but is the same. One day it will become a variable speed disc sander. I find the rotating head keeps coming loose and I loose my alignment with the tail stock. 

+2 on using your tail stock as you rough down your blank

+2 on slower speed at start up.

Dave The Turning Cowboy


----------



## DaveTTC (May 25, 2012)

cuerodoc said:


> +1 on the shelf and then adding bags of sand.
> 
> I have one similar to that one- got it when I decided to venture into turning not using a shopsmith--that was the start of my descent into the vortex (startin to sound like admitting a problem--:no. Adding the sand really helped knock down the shake. Then after you hollow some out of the bowl i believe it'll spin more true. (And yes I do have more than one big boy toy---I like to have multiple projects going:yes
> ALWAYS check the screws on the plate after some turning-- have had some suprises that I don't want to repeat.


Hijacking the thread here - 

Hey there doc, how do you find the shopsmith compares. I recently purchased an old one that needs some restoration. What do you think of yours?

Dave The Turning Cowboy


----------



## rrbrown (Feb 15, 2009)

duncsuss said:


> Thanks biscobob and firehawk ... I'll have to check the nuts and bolts.
> 
> Also I'll investigate whether it's possible to put an electronic speed control in line with the motor on this puppy -- the gearing is one of those mechanical thingummies (Reeve drive?) which I know will not preclude it, but the motor might not be externally controllable.


That motor should have brushes not a capacitor. So a speed on troll for a router should work. 

I agree with all those about adding a shelf and bags of sand. Make it heavier however you can.


----------



## cuerodoc (Jan 27, 2012)

DaveTTC- 
The shopsmith is adequate but has limitations. There are adapters so you can use chucks. Recommend getting the heavy lathe tool rest, makes a big difference. Motor bogs down easily, and blanks need to be pretty round or it dances a lot-- it has a big throw too. The variable speed is nice but even the lowest speed is sometimes too fast---there's an attachment for that too--a speed reducer (It's only $$). Nice in thought but find that it bogs easily. ebay is good source for stuff. I did turn some nice early bowls though


----------



## Itchytoe (Dec 17, 2011)

Holy thread revival batman! 

Anyway, yea, uhh more weight will make things more solid, and round doesn't always mean balanced.


----------



## duncsuss (Aug 21, 2009)

Itchytoe said:


> Holy thread revival batman!


Oh yeah ... to the point it took me a while to remember why I was asking the question :laughing:

Still, thanks everyone for the advice and information. I'm planning on letting the HF lathe go now that I've got my Nova 1624-44, put that cash towards a headstock handwheel and/or vacuum chuck.


----------

