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Sanding inside hollow forms rig

Randy Anderson

Randy Anderson

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Location
Eads, TN
Website
canthony.gallery
In doing larger hollow forms the opening is large enough to see a good bit into the form. I need to do more cleanup and sanding to make it look nicer, to a point. I made this little tool recently and so far working well. It's a DeWalt 90 deg drill adapter, a 10" flex drill extender and a piece of 3/4" angle. I can hold on to the angle, hold my small sanding drill motor on the end of the flex extender and with a sanding disc on the 90 deg adapter do a good job of sanding up to about 9-10 inches, depending on the opening. Not doing a fine finish sanding but can get it looking a lot nicer than just doing my best holding paper inside or paper on the end of a stick while the piece spins. The tie wraps work OK for now but hose clamps or even some epoxy will end up better I think. The tie wraps can slip or get loose. The low profile of the DeWalt 90 deg head fits into some fairly small openings.

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This could be a promising thread. I use a wooden dowel with a slot cut in the end. Wrap a strip of sandpaper through the slot and around the dowel end. I'm sure there are better ways to sand in a hollow form and look forward to trying out some new ideas. I have a DeWalt 90 deg adapter and may to try and rig something up.
 
I have made something very similar one of the drawbacks is the right-angle drive can have a short life. I still use them but mostly use the inertia sanders for the internal work. I run my inertia sanders on a couple of skateboard bearings which has proved to be very successful
 
Nice idea. I'll look into that. I am hollowing out a piece on the lathe now. How do you get the round shaft of the sanding disc to match up to the hex shape of the 1/4 inch drive head?Thanks
 
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Denny Nebgen said:
Nice idea. I'll look into that. I am hollowing out a piece on the lathe now. How do you get the round shaft of the sanding disc to match up to the hex shape of the 1/4 inch drive head?Thanks
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You have to purchase hex shaft. I got some from Woodturners Wonders
 
Denny Nebgen said:
I have trouble with the forceps as I only can get a small portion of the paper onto the surface at a time.
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I use a piece of Kaizan foam and wrap the paper around it , then good contact with wood
 
What’s the smallest size opening this rig will fit into Randy? Silicone might work well to hold it together. I would wipe down the angle / parts to clean any oily residue off first.
 
Randy Anderson said:
In doing larger hollow forms the opening is large enough to see a good bit into the form. I need to do more cleanup and sanding to make it look nicer, to a point. I made this little tool recently and so far working well. It's a DeWalt 90 deg drill adapter, a 10" flex drill extender and a piece of 3/4" angle. I can hold on to the angle, hold my small sanding drill motor on the end of the flex extender and with a sanding disc on the 90 deg adapter do a good job of sanding up to about 9-10 inches, depending on the opening. Not doing a fine finish sanding but can get it looking a lot nicer than just doing my best holding paper inside or paper on the end of a stick while the piece spins. The tie wraps work OK for now but hose clamps or even some epoxy will end up better I think. The tie wraps can slip or get loose. The low profile of the DeWalt 90 deg head fits into some fairly small openings.

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This is a creative solution, to what for me as a beginner is a difficult problem. Nice to have this information. I am planning a segmented turning where this may come in handy if the dowel and sandpaper do not work.
 
Russ, I keep a thick foam pad on my sanding mandrels (see pic) and with the pad it's about 2 1/2" tall at the head but, I've used in openings a bit smaller by tilting it on the way in. You could use a thinner foam pad on a smaller opening. I'm usually using it farther inside than right at the opening and if your piece flares out wider from the top down then you will have more room. I still do the top 1-2" inches of the opening by hand since I want those to be as nice a finish as the outside. The sanding jig really helps for those stubborn tool marks down inside where folks will always run their fingers to feel it or will show when the finish is on.

Also, I recently picked up a very long 1" scraper at an estate sale and ground the end as a NR scraper with a round shape that tapers far back on both sides. I use it to clean up way down into the neck of the piece. Not hard and really does a nice job cleaning up down about 4-5" inside, depending on the shape and curve of your opening.
 

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Richard, I've used sandpaper on the end of dowel or stick, foam pad under the paper, etc and while it works to some degree it can be tedious. My long NR scraper and this jig make it a lot easier for me to hit just the trouble areas without spinning the piece and working the dowel around. I can get a very nice surface well down into the piece. Farther than my fingers can hold onto a piece of sandpaper.

It takes a bit of practice to get the hang of holding the jig and the pressure/angle inside the piece. It's not hard but standing in front of the lathe I find sanding at the 4pm to 6pm area works best for me. Moving around in and out with light pressure. You'll need to lock your spindle since it will want to rotate as you sand.
 
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Randy Anderson said:
In doing larger hollow forms the opening is large enough to see a good bit into the form. I need to do more cleanup and sanding to make it look nicer, to a point. I made this little tool recently and so far working well. It's a DeWalt 90 deg drill adapter, a 10" flex drill extender and a piece of 3/4" angle. I can hold on to the angle, hold my small sanding drill motor on the end of the flex extender and with a sanding disc on the 90 deg adapter do a good job of sanding up to about 9-10 inches, depending on the opening. Not doing a fine finish sanding but can get it looking a lot nicer than just doing my best holding paper inside or paper on the end of a stick while the piece spins. The tie wraps work OK for now but hose clamps or even some epoxy will end up better I think. The tie wraps can slip or get loose. The low profile of the DeWalt 90 deg head fits into some fairly small openings.

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That looks like a handy tool. I purchased a 1" diamond sphere with shaft on ebay (different sizes and grit are available) to see if it would work for sanding. It works great for some internal sanding applications and could work with the 90* DeWALT elbow. An adaptor may be needed to attach it to the elbow. It may take a little getting use to because it will bounce at first so don't give up.
 
hollowform sanders.JPGWhat you're looking at here are two lengths of twisted armature wire with a piece of lambswool buff wrapped around one end and secured with HVAC tape. Velcro strips adhere readily to the HVAC tape's metallic surface. Hook and loop sandpaper strips are secured by the velcro. The sanding ends are 1-1 1/2" in diameter. I can't hollow through a smaller hole than these will fit. Nobody but another woodturner is going to judge the interior surface of a hollowform anyway!
 
I've made a few modifications since my first setup. This one uses thick wall PVC, heat one end to insert the 90 deg head tight and used a couple of the flexible drill adapters inside the tube. Overall length is 28". So far easier to use than the first version and can go deeper when needed. On a deep vase with inclusions I want to be able to do some cleanup further inside. Thinking on how to add a flexible shaft drive setup so I don't have to hold my small drill motor on the end. Not hard but not convenient either.
 

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What have found if you're going to use off the shelf right angle drive you have to buy quality, no el cheapo ex china. The quality brands work well but have another issue in so much as the heads can be over large for hollowing work. I have had a go making my own with some success. But the other hassle is getting the dust out from small openings, I have tried regulated airflow this works with a down side of dust every where in the shop. So the obvious choice fitting a vacuum line to the internal sander with bulking it up, its a work in progress.
 
Hughie, the 90 deg head I have is DeWalt and has held up so far after many hours of use. If and when it does wear out they're easily replaced and the RPMs I use are fairly low relative to the rating so I expect it to last a while. The head on it is small for what I do but with a sanding pad attached it's not something you'll get into a very small opening on something like a twig pot. Not sure how small you are working with but I put a piece of thin wall PVC on the end of my dust collector hose and just insert it from time to time while hollowing and sanding. Works fairly well.
 
Larry Mercier said:
Hi Neil, what gauge is that wire. How did you get such a nice twist on your tool?
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Wow, missed seeing your question. You need 3/8” diameter wire. You can bend it to fit internal curves and it still hold the sandpaper in place. 1/4”wire is not stiff enough to use. The twist is just the two ends of the wire gripped in a vise; insert a rounded piece of stock, ideally the size of the end loop you want, then turn slowly until complete. It’ll take some searching to find that larger diameter armature wire (unless you want to split the cost of a spool with friends). I no longer remember where I sourced it, just remember hunting a long time for it.
 
Randy Anderson said:
Hughie, the 90 deg head I have is DeWalt and has held up so far after many hours of use. If and when it does wear out they're easily replaced and the RPMs I use are fairly low relative to the rating so I expect it to last a while. The head on it is small for what I do but with a sanding pad attached it's not something you'll get into a very small opening on something like a twig pot. Not sure how small you are working with but I put a piece of thin wall PVC on the end of my dust collector hose and just insert it from time to time while hollowing and sanding. Works fairly well.
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Randy I had a look at the Dewalt and agree they would be one of the best thats available where I am
 
Neil McWilliams said:
Wow, missed seeing your question. You need 3/8” diameter wire. You can bend it to fit internal curves and it still hold the sandpaper in place. 1/4”wire is not stiff enough to use.
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Umm, I think you might want to get better measurements? 3/8 diameter (0.375 inch) is Double Ought (00) Gauge wire , twist two of them together, you've probably got 3/4 inch thickness to deal with , which is QUITE the handful.. add in a radius and loop, you've likely got about a 2-1/2 inch to 3 inch loop, I'd suspect you're shooting for perhaps 3/16 diameter (half of a 3/8)?
 
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