Hollowing rig questions

Tom Baugues

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Lafayette, Indiana
I have finally started to weld up a hollowing rig system. Today I welded up a "D-Arm" from 3/4" stainless steel shaft. I also welded up a back support rest....which brings me to my first question. I'm building a rig like this https://www.lylejamieson.com/tools/tool_howto.asp . It calls for a backrest of anywhere from 30-38" across. One place one his website he says 30-32" and another he says 38"...My question is....do I really need it that wide? In the case of 38" he states that it should have 10" in front of lathe and 28" in the rear.
I know some of you have made your back rests so that you can slide them forward and back and I may make mine that way too...just looking at my options. I'll get some photos of it all in the next couple of days.
I also will then be trying to figure out how to make the cutting tips. My boring bars will be 3/4" bar as well but I need to know how to attach the cutting tools to the tip of the bars.
 
Tom, I'd recommend making the back rest as wide as possible. You'll be glad to have the extra movement capability.

For mounting the tips, search the forum for a thread I started a couple years ago about making boring bars. I think the thread title is something like 'A boring day in the shop'. (I'd search for you, but I'm on my phone, so pasting links is a pain.)
 
I agree with Vaughn and would go around 36". You will be glad for the extra movement in the unit. Mine is around 34 1/2" and sometimes I wish I had a couple more inches.

I welded up my back rest at 32" however I still need to mount it to the base so maybe I'll come up with a way to slide it on the base forward and backward a few inches to give me that extra length. My lathe sits up against a wall and even at 32" I would still need to pull it away from the wall to use it. I thought I was just saving myself from having to pull it from the wall but I guess I just will have to do that when needed.
 
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I found it, Tom...

http://familywoodworking.org/forums/showthread.php?t=13507

Note that in post #29 I make a correction on the size of the tool bits. They were 3/6" bits, not 1/4". :doh:

Thanks Vaughn, that helps alot. I have quite a bit of stainless steel shaft here now of several different sizes to make tools with. I saved several old shafts from some machine repair work that I do. I should have enough for a dozen or so tools if needed. I'll now have to be on the look out for square HSS bits.
 
...I'll now have to be on the look out for square HSS bits.

Look no further...

http://www.use-enco.com/CGI/INSRAR?PMSECT=0000000747

Pick a size and material. :D In my experience, the HSS ones work just as well as the cobalt ones. (As I understand it, metalworking benefits from using the cobalt bits because they withstand high temps better. Cutting wood doesn't get the bits hot enough to make a difference.) I've bought the 2" or 3" long ones and cut them (snapped, actually) into two shorter bits.
 
Tom if you have a local HF you might look at this too...I have bought a few of them and they work great for what you want to do.

>>>LINK<<<
 

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Well, here is my hollowing rig setup. It is all 3/4" stainless steel rod. I am not sure how long the boring bars should be? I suppose as long as I want? The only one I made so far is the one in the photo which is 21" long with a 3/8 drill bit cut and shaped. Not sure how it will work.
Now, before someone says it...I know that I need a safety pin in the back of the D-arm. I have not been able to find one just yet. (edit) found one tonight.

Jeff, thanks for the link to the Harbor Freight bits. I saw those once when I was there but was not completely sure that was what I needed.
 

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Looking real good, Tom. :thumb:

You may find that for most hollowing, having a shorter boring bar can be an advantage. First, shorter bars typically vibrate less. Second, the longer the boring bar and D handle are, the more space you need behind the lathe when you try to enter the vessel at a sharp angle, like when you're cutting the just inside the opening and along the shoulders. Fortunately, it sounds like you've got plenty of materials to make multiple boring bars. You can make yourself a whole assortment of 'em and changed them around as the need arises.
 
Looking real good, Tom. :thumb:

You may find that for most hollowing, having a shorter boring bar can be an advantage. First, shorter bars typically vibrate less. Second, the longer the boring bar and D handle are, the more space you need behind the lathe when you try to enter the vessel at a sharp angle, like when you're cutting the just inside the opening and along the shoulders. Fortunately, it sounds like you've got plenty of materials to make multiple boring bars. You can make yourself a whole assortment of 'em and changed them around as the need arises.

I certainly agree with Vaughn, both in that you have done fine job, and it looks great, and that having a short bar or two is nice. Since you are making them yourself, why not knockout a short, medium and long bar?

Cheers!
 
Tom, that is a nice capture rig. I love to build tools and have built one of these, a steel snake and a small hand held rig too. You will enjoy it I am sure.
 
And what is meant by back rest is it the part the back of the tool steel holder slides through that captures it & keeps it from twisting or turning?

Yes Bart. The backrest is just that...the "rails" that the D-arm is sliding on. It keeps the whole arm from getting out of position. With a set up like this you can actually cut out a bowl with just finger tip control on the boring bar. (so I'm told...I have yet to try it out).

I hope to spend this weekend making several boring bars with various cutting tips.
 
Tom, I like what you did there... looks good in stainless... I see what you mean about having to pull away from the wall too.... I'll be real glad to solve that problem for you..:D... my lathe sits in the middle of the shop with the tail stock perpendicular to the wall, so that looks as if it would fit fine in my shop and you wouldn't have to get all hot and sweaty moving your lathe.. :D:D

Are your going to put a laser on it too?
 
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