Swivel Rocker Chair Bases

[algale]

I have a pair of upholstered chairs from the early 60s that originally had swivel/rocker bases. One base got removed and lost during a move. Over the decades, the other base didn't rock as smoothly as it once had.

Recently, my wife went to reupholster the chairs and removed the swivel/rocker base. Upon examination, it appears that the springs that connect the runners and rockers had twisted them partially away from the stretchers, towing them inward so that only the rockers' inner edges were in contact the the runners inner edges. There was uneven wear and a groove.

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I toyed with the idea of knocking the unit apart, filling the grooved runners with an epoxy and sawdust mixture and re-doweling the stretchers. It seemed like it would be just as easy to build one from scratch

First step was to make the rockers/runners.

After tracing one original rocker and one original runner, I rough cut out one of each on the band saw and sanded them to the line with the drum sander.

Only after making the first runner/rocker did I remember I had the Shopsmith pattern sander! For those who don't understand how it works, this is like a pin router for a sanding drum. The "pin" is actually a circular piece of plexiglass or similar material that sits under the drum and is adjusted so its font edge is even with the drum. You attach a blank to your pattern with the double sided tape and then run the pattern against the pin. Because the pin is slightly larger than the diameter of the drum, the work piece only makes contact with the sanding drum at the front edge of the drum along a line of tangent. Eventually you end up sand a perfect duplicate of your pattern. Unfortunately
I didn’t take any in-process photos but you can see the pattern sanding guide under the drum in this photo.

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Next up was the stretchers. The stretcher are pretty basic but after I cut them I found the end cuts were slightly out of square. Surprising because I cut them on my Incra5000 sled, which is usually spot on. So it was time to mount the 12" sanding disc and touch up the end cuts, first doing one end on all 8 stretchers and then turning them around and doing the other end. Getting them all back to the same length was made possible using the depth stop on the quill advance. Sanding to length and cleaning up/truing up end cuts with the sanding disc is something I don't usually do because my cross cuts are usually square and glue ready. But I was glad to have the Shopsmith's functionality to fix the stretchers.

With the stretchers all nice and square and even, it was time for some joinery. I toyed with the idea of mortise and tenon joints but the originals were actually doweled so I decided to do likewise. Each of the 8 stretcher needed four dowel holes drilled (2 in each end). And since the stretchers were 14.5" long, it was definitely time to take advantage of the Shopsmith's horizontal boring capabilities. The set up is shown in the photos. The rip fence was used to back up the work and the miter gauge and pistol grip clamp. I used a pair of flip stops to control the spacing on the dowel holes. After drilling the first two holes and test fitting a couple of dowels, it became apparent that the holes were not the same depth -- even though I had set the depth stop. A little sleuthing revealed that the rip fence was slipping on the rails from the pressure need to advance the drill. I reset and the fence/depth and stuck a clamp on the fence rail to keep it in place. It did the trick and I was drilling like nobody's business.

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To drill the matching holes in the runners, it was easier to use some dowel centers in the stretcher to mark the hole placement and then simply line up the brad point on the drill bit with the tiny hole made by the dowel center.

First runner/stretcher assembly glued up and looking pretty good! Everything seemed square and well aligned.

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The original base to the swivel rocker is a 20" x 20" twelve sided polygon (dodecagon) cut out of 3/4 mahogany veneered plywood. I don't have mahogany veneered plywood so I decided to make it out of solid wood I had on hand. It was a bit of a mix and match job but these bases and really the rockers are never seen because the upholstered chairs have "skirts" that go down to the floor.

I was a bit apprehensive about gluing up such a large panel that I couldn't run through my jointer or planer, but I did have a set of 24" Shopsmith double bar clamps. I bought these a few years back for a project that got put on hold so this was a first.

To my surprise, my first dry fit using the double bar clamps was a bit off. Checking the pieces, one or two had a little twist to them that I was able to joint out. But even after doing that, the dry fit was off for some reason, even though the faces seemed flat and the edges square.

Luckily the Forum really came through in response to a question I posted and I learned that there was probably some small degree of error in my jointer fence that was being multiple across the many pieces being used to assemble the panel and that I needed to cancel out this error by alternate the jointed faces (up and down) to compensate.

Since I had marked the jointed faces and the witness marks were still visible so I was able to alternate them. After making that adjustment, the dry fit was much better and I glued up one and then the other panels. They really came out nice and flat right out of the double bar clamps, needing only a light finish sanding to completely level them! It's nice to know that I can now make projects out of assembled panels that are wider than I can run through my jointer or planer and not have to rely on plywood.

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With the panels made, it remained to turn them into dodecagons (12 sided polygons) like the original. I could have used the pattern sander to do this operation, but I decided that since these were all simple, straight cuts (rather than curves) this was a great opportunity to try out a technique that Nick demonstrated in a Sawdust Session and to cut the bases on the table saw using an improvised overhead fence.

Looking around the shop, I settled on my homemade rip fence extension/dado fence. Just by luck, when I inverted and clamped to the fence it was at a perfect height. The edge overhead fence was aligned with the outside edge of the blade,

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Then I simply screwed the original base to the panel, adjusted the blade height and made 12 cuts per base, rotating the panel between cuts and guiding the original base's edges along the overhead fence. It turns out this is a super easy technique and while I was apprehensive making the first cut, it actually felt very stable and safe.

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Here is the original bases and my two new bases.

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More to come, including installing the spring mechanisms on the rockers and the lazy Susan’s.

[algale]

Well, this post generated no interest. Here’s the finished products. Springs and lazy Susan’s installed along with the “arms” that attach to the seat frames.

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[RFGuy]

Well, this post generated no interest. Here’s the finished products. Springs and lazy Susan’s installed along with the “arms” that attach to the seat frames.

I wouldn't say that is exactly true, but maybe some of us just didn't post before now. I always learn something from your posts and this one was no exception. I never knew there was a pattern sander for the drums on the Shopsmith. I am not sure if I need it, but it is certainly something to consider for future projects. Thanks for bringing it to my attention. Also, those rocking chair bases are looking really nice!

On the rip fence slipping with horizontal boring that you had...I have had this every time I attempt to use the horizontal boring function. Yes, I use clamps to attempt to hold the fence, but it still slips at least a little. Just my opinion here, but I really don't see the horizontal boring being a "great" feature on the Shopsmith. Maybe I am the exception, but it seems like I always have to go to extraordinary lengths to get solid alignment for it in x and y axis and then the z axis just keeps sliding due to the fence. However, I do like the Incra miter gauge being used to try to maintain alignment as you showed in your pic.

[algale]

On the rip fence slipping with horizontal boring. I have had this every time I attempt to use the horizontal boring function. Yes, I use clamps to attempt to hold the fence, but it still slips at least a little. Just my opinion here, but I really don't see the horizontal boring being a "great" feature on the Shopsmith. Maybe I am the exception, but it seems like I always have to go to extraordinary lengths to get solid alignment for it in x and y axis and then the z axis just keeps sliding due to the fence. However, I do like the Incra miter gauge being used to try to maintain alignment as you showed in your pic.

I had no slippage when I drilled into the face grain on the rockers/runners. But the end grain on the stretchers was really hard to drill; had to apply a lot of pressure and without a clamp it slipped. I will say that it would have been hard to drill those stretchers except in horizontal mode. Maybe if I had a stand alone doweling jig?

Anyway, thanks for reading and commenting. I learned some new skills. Hadn't used either the pattern sander or done the overhead table saw fence or glued up big panels before. So it was a learning experience.

By the way, the finish is just pure tung oil. One coat only put on thick.

[RFGuy]

On the rip fence slipping with horizontal boring. I have had this every time I attempt to use the horizontal boring function. Yes, I use clamps to attempt to hold the fence, but it still slips at least a little. Just my opinion here, but I really don't see the horizontal boring being a "great" feature on the Shopsmith. Maybe I am the exception, but it seems like I always have to go to extraordinary lengths to get solid alignment for it in x and y axis and then the z axis just keeps sliding due to the fence. However, I do like the Incra miter gauge being used to try to maintain alignment as you showed in your pic.

I had no slippage when I drilled into the face grain on the rockers/runners. But the end grain on the stretchers was really hard to drill; had to apply a lot of pressure and without a clamp it slipped. I will say that it would have been hard to drill those stretchers except in horizontal mode. Maybe if I had a stand alone doweling jig?

Anyway, thanks for reading and commenting. I learned some new skills. Hadn't used either the pattern sander or done the overhead table saw fence or glued up big panels before. So it was a learning experience.

By the way, the finish is just pure tung oil. One coat only put on thick.

Where did you get your rip fence stop blocks from?

Maybe some day I will make a jig to attach to the rip fence with the sliding t-nuts in the right hand side miter slot. If I do something like this, then I would have a solid platform for the rip fence to push against so that horizontal boring wouldn't cause sliding of the rip fence.

[algale]

Where did you get your rip fence stop blocks from?

Shopsmith Flip Stop.

https://www.shopsmith.com/ownersite/cat ... cestop.htm

[JPG]

Not having much experience with the 510 fence for horizontal boring, I do not quite understand the slipping fence issue. I have not experienced slippage with the Mark 5 rip fence with typical pressure. I do a lot of boring horizontally but often have the table vertical and rest the work piece on the fence.

Yes end grain boring requires great force. I tend to back that up when possible.

I do believe the screw clamp of the Mark 5 is capable of greater(tighter) clamping than the lever clamps on the 510/520. The gorilla can prevail when necessary!

P.S. VERY nice job Al!!!

[masonsailor2]

Came out pretty nice ! What kind of wood was that. Beautiful stuff !
Paul

[BuckeyeDennis]

Nice work, Al! Those chairs should be better than new.

I recall reading the first paragraph or two of your original post, but I just finished reading the entire post. I probably meant to read it all later when I had more time, but then the thread never got bumped until today.

On the fence-slipping issue, have you lubricated the locking-handle cams on your fence? My 520 fence used to be very stiff and difficult to actuate. I finally gave the cams a good shot of powdered graphite, and the difference was amazing. The cam friction dropped so much that I could adjust the fence clamps to grip much more tightly, and still not be difficult to actuate. I don’t recall having any fence slippage problems after that.

[algale]

N=
On the fence-slipping issue, have you lubricated the locking-handle cams on your fence? My 520 fence used to be very stiff and difficult to actuate. I finally gave the cams a good shot of powdered graphite, and the difference was amazing. The cam friction dropped so much that I could adjust the fence clamps to grip much more tightly, and still not be difficult to actuate. I don’t recall having any fence slippage problems after that.

I have, but not in a while. I'm overdue for some Shopsmith maintenance and will play around with the fence clamps and add some graphite.