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  1. #1
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    Default Vacuum Chucks - what can and can’t they do?

    I’m in the process of getting a vacuum chuck working, and was wondering what the perceived wisdom is as far as what size and weight bowl you can mount and what speeds are considered safe. I normally err on the side of caution, but also don’t want to end up finishing bowl bottoms at 400 rpm if 1000 rpm is safe.

    All I’ve been able to find looking online is that you get over 100kg clamping on a 150mm diameter chuck, but no-one has extrapolated that to a safe size of bowl or speed.

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  3. #2
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    It is hard to give a diffinative answer to this . Even a finished bowl may not be in perfect balance and as the RPM is increased, the centrifical force will increase any imbalance and may cause the bowl to slide sideways and fly off .If I think there is any risk I always keep the tailstock in position as long as possible, then slow down to finish off the the last little bit of the bottom.
    Ted

  4. #3
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    All comes down to 'best guess' and a lot of luck. I set one up many years ago on my Stubby and it got less and less use as my turning skills improved. What I found happening was that as my bowls got thinner, the chance of getting a good seal for the vacuum reduced as well so I just about gave up on it . . . and if you do get a good seal, the bit you turn off the base can sometimes allow too much air through and . . . DAMHIKT! I did fire it up just recently for a special little job, but once again, there was air getting through the timber and I couldn't get enough vacuum. Over-rated methodology in my book - Longworth chuck and some packing tape cover just about everything you need
    .
    Updated 8th of February 2024

  5. #4
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    Quote Originally Posted by TTIT View Post
    Over-rated methodology in my book - Longworth chuck and some packing tape cover just about everything you need
    I may be weird, but I'm saving up to become eccentric.

    - Andy Mc

  6. #5
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    Colin, I don't know if this is allowed, but I invented the Tail Stock Steady back in 2011. It allows you to remove your tenon, glue block or clean up a recess while still safely between centers. If I had the marketing skills necessary to sell it properly, it would probably cause all the other devices to become obsolete because it is a much cleaner and safer tool to use. Also, you questioned speed. So far, speed at 3000 RPM, while finishing from 3" OD up to 15" OD has not been a problem if the friction plate, rim chuck or plug is set up properly.

    I have a bunch of videos on youtube. All are segments from a 2-3 hour video, but every now and then, something happens that needs to be seen. The link at the end of this paragraph is one that shows how well the TSS performs. This piece shown should have flown, but stayed between centers after that serious catch. I was teaching a friend how to turn. The piece he is removing the tenon on is about 12" diameter. When he got that catch, any other work holding device on the market today would possibly have lost this piece. In the 10 years I've used the TSS, I have had at least 20 catches like in this video, and I was able to finish those pieces because it stayed between centers. Copy and paste the following link to Youtube and you'll see why this piece stayed between centers. Possible launch????? - YouTube

    My website is Wood Turning Tools | Tucson | WoodTurners WorkHolding Solutions. Look at some of the things I've done and you will see that a vac chuck just couldn't do the job.

    There are 2 people on this Forum that has one. They will have to chime in and let you know what they think of the TSS. I can only make my thoughts sound like a sales pitch. ............. Jerry (in Tucson)

  7. #6
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    Thanks for the replies gents. I’m aware that vacuum chucks have limitations, but then so does every method of chucking that I’ve seen.

    I’ve not used a longworth chuck, but have used cole’s jaws on a Nova chuck and as far as I can work out the extra that I’d get from a longworth chuck are size and speed of adjustment.

    Nubs, I like the look of your system, but I’d still need a different method for a natural edged bowl.

    In fact the downside to most methods is that they can’t easily hold natural edges bowls, and natural edges are a large part of the motivation for using a vacuum chuck at this stage. I’ve seen the YouTube video where someone tries to convince you to use a vacuum chuck for the entire bowl, which seems over the top to me. I do believe that they have their niche, I’m just not sure how far I can push it, so I’ll start slowly, keep the tailstock up as long as possible and take small cuts as I build up a bit of confidence with it.

  8. #7
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    Quote Originally Posted by Colin62 View Post
    Nubs, I like the look of your system, but I’d still need a different method for a natural edged bowl.
    For this I'll simply mount a blank roughly shaped to a similar profile to the inner bowl. I tape a layer of 1/2" foam over it to make up any profile difference and then a layer of rubber to provide friction grip. The little rubber mats used for opening tight jam jar lids are ideal for this.

    This method does need tailstock support to keep everything in place, Nubsnstubs' tailstock steady would probably be of use here, but I'm used to working around the point.

    Personally I dislike vacuum chucks, mainly because the overheads involved make it a major investment for very little gain... and possibly a whole world of pain.
    I may be weird, but I'm saving up to become eccentric.

    - Andy Mc

  9. #8
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    Quote Originally Posted by Skew ChiDAMN!! View Post
    Personally I dislike vacuum chucks, mainly because the overheads involved make it a major investment for very little gain... and possibly a whole world of pain.
    I’ve always felt that it wasn’t worth the expense to buy or the effort of making a system from scratch, but a local supplier was clearing stock and I got the essential bits quite cheaply and it’s easy enough to hook up to a standard compressor. I’ve also mostly avoided natural edges bowls becuase I didn’t have a reliable way to reverse them to clean up.

    I have no intention of starting a scientific study of exactly when different sized bowls go into orbit when using vacuum chucks but I think I’ll post back here when I’ve used one for a while. They’re certainly not a silver bullet, but then what is?

  10. #9
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    Quote Originally Posted by Colin62 View Post
    Thanks for the replies gents. I’m aware that vacuum chucks have limitations, but then so does every method of chucking that I’ve seen.

    Nubs, I like the look of your system, but I’d still need a different method for a natural edged bowl.

    In fact the downside to most methods is that they can’t easily hold natural edges bowls, .
    Colin, I'm not trying to get into a pissing match, but of all the natural edged pieces I still have, over 20 of them of varying sizes, were really easy to mount. For smaller pieces, I make a form I call a plug. It is nothing more than a limb/branch larger than the form needing the bottom cleaned up. It has a tenon on one end and is turned to fit the opening if it's a closed form. I then turn a flare to match the flare on the opening. That pretty much centers it if the neck fits on the flare properly. The tailstock centers the other end. These are mostly smaller pieces.

    For larger pieces, I get usually two pieces of MDF, sometimes 4-5, and glue them until they are thick enough to allow it to hit the bottom and still have enough room to fit onto my Chuck Plate, another of my inventions.

    The inside bottom of my form will be completed without finish most of the time. I do not have the plug fit the contour of the bottom of the piece. I normally stop short by at least a 1/2", then back cut the end of the plug with a concave shape. What that does is spread the contact point outward, and gives it a more stable and better grip without slipping when a catch is incurred. I sometimes use the drawer liner material that SkewChiDAMN might be talking about, but I don't normally use it because of the successes I've had without it. The tailstock will center your piece. Then, the tenon is turned off to a nub about 5/8" diameter.The bottom is then embellished if there is enough depth.

    For me, I then take my banjo and move it forward until the tool rest makes contact with the bottom of my piece. I lock it and pull away the tailstock. The piece is still centered, and the TSS is inserted and I continue with cleaning up the bottom.

    Only 2 Aussie turners have my TSS, but the method described above can be done without it. You just turn the tenon down to a small nub you are comfortable with, then remove the piece from the lathe and complete your piece.

    I can get pictures if you would like to see my method, but you will have to ask. ................. Jerry (in Tucson)USA

  11. #10
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    Quote Originally Posted by Nubsnstubs View Post
    Colin, I'm not trying to get into a pissing match
    Jerry, I’m sorry if I gave the impression that we’re arguing, I see it as a discussion and an opportunity to hear how others work and hopefully to learn a little from that. I know sometimes it’s frowned upon to digress from the topic of the thread, but in my experience often the best nuggets of knowledge come from diversions and at the end of the day I come here to chat with like minded people, to learn what I can from those that know more than me, to discuss issues and hopefully sometimes to be able to pass a little knowledge on where I happen to have a little experience.

    While this thread might not have given me any definitive answers, we have some general recommendations and it has also thrown up alternatives and other ways of working. There is almost always more than one way of doing the job, and choosing which to use is often based more on what we’re comfortable with and what we have available to us at the time. If I’m visiting one of my kids, I’ll sometimes pick up a little bowl I turned many years ago, before I even owned a scroll chuck, and usually it’s as well finished as something I made last week. Yet if asked, I’ll immediately recommend a scroll chuck as an almost essential piece of gear.

  12. #11
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    Colin, sorry for the late reply to your questions. I am lucky to be one of the Aussies that has one of Jerry's Tailstock Centres and here is why I sought him out to see it in real life, because as you know some things look good in magazines and on the interweb, but fail to achieve in real life.
    My journey started after I exploded two different 450mm/18inch platters of very highly figured wood while trying to remove the tenon whilst held in a longworth style chuck. It turned out that the thin platter was pulled out by the bowl gouge biting into the timber as it was so thin 6mm/1/4inch thick. Partly my fault, but when you have a 600mm/24 inch chuck with 8 red plastic holders spinning around beside you, you don't notice the flexing until the inevitable. I searched the interweb and found Jerry's videos, liked what I saw and during a visit to him in Tuscon he gifted me one of his centres. I had plans to do a review of it on this forum, but sadly due to me having to move my timber store and then a lot of ill health I have not seen my lathe in a long time.
    Well I am slowly getting better and over the Christmas break I found the lathe so in the near future I will post the review here.
    I finished off several platters when I first got home using the TSC and it worked perfectly for me by taking the flex out of the wood.
    Jerry demonstrated it's use on one of his wild winged NE creations and thats what sold me on it's versatility.
    Rgds,
    Crocy

  13. #12
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    Quote Originally Posted by Colin62 View Post
    Jerry, I’m sorry if I gave the impression that we’re arguing, .
    No Colin, you did not give me that impression. It's just a choice of bad wording on my part. Hadn't finished my 2 cups of coffee yet when I replied.

    I also learn from off track or differing responses from people. You take what they say more seriously and evaluate it to see if there is any validity to it. Most times, 2 heads are better than one. Thank you. ........... Jerry (in Tucson)USA

  14. #13
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    Quote Originally Posted by Old Croc View Post
    . I searched the interweb and found Jerry's videos, liked what I saw and during a visit to him in Tuscon he gifted me one of his centres.
    Jerry demonstrated it's use on one of his wild winged NE creations and thats what sold me on it's versatility.
    Rgds,
    Crocy
    Well hell, Richard, if I had known I was a hunted man, I would have gifted you 2 of them. Hehe I don't think you told me that. Actually seeing how the TSS works in person gives you a whole different understanding of it advantages. I'm glad you found me and we can call each other friend.

    Before inventing it, I had plans for a Longworth Chuck. I looked back at the donut chuck I made, and remembered the bolt heads sticking out, and the time I brushed my knuckles up against them. Shudder at that thought, and looking at those 1" nubs sticking out from the face of Cole Jaws and Longworth jaws was even more distressing, I decided to try something different. It took a year for a Cabinet Maker to actually make 17 Live centers and a wheel mount for them before I hit on what the Tail Stock Steady is now.

    The introduction of the TSS is like about 40 years ago when wood turning chucks first came into the wood turning world. I was one of those guys that couldn't see the potential. It wasn't until 2010 that I got my first, a Nova G3. I now have 4 SN2's, and am looking for a couple more..........In about 20 more years, the TSS will more than likely become a tool that will be a part of more than 60% of the woodturners tool kits. Too bad I won't be around to see it or be around to be part of that transition. ............. Jerry (in Tucson)

  15. #14
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    I have a vacuum pump that I had for other purposes but have never found a need to use it for chucking.

    However, I prefer to leave the feet of my bowls, platters and closed forms. Why remove such a design and decorative feature that can add value to the piece!
    Stay sharp and stay safe!

    Neil



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