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I was reading Lon Schleining’s The Workbench and I am intrigued adjustable bench built by Curtis Erpelding for Gary Blaise. It is shown on page 19. Looks like a traditional bench with threaded rods installed into each leg connected by a chain and sprockets to a hand wheel. Looks like it works similar to the height adjustment on a four-post thickness planer.
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I looked on line at the resources mentioned, McMaster Carr and Johnston Supply but I didn’t find anything similar to the parts mentioned in the book. Just wondering if anyone has built a similar bench and if so where did you get the parts for the adjustment mechanism?
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Thanks,
Bob T.
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Replies
I have been reading the exact same book and looking at the exact same thing. Hope someone will chime in.
Lyle
McMaster-Carr carries Acme rod and nuts which is what you would want to use for this type of application. I'm not an Engineer so I can't tell you what size you would need. They also carry hand wheels, chain and sprockets that would be needed.
The threaded rod would need to spin free at the top while there should be a flange nut fix mounted in the the leg. All the sprockets would be fixed to each Acme rod. You would have to figure out a coupling if you want to have the hand wheel removable. I would also recommend a chain tensioner rather than try to figure the perfect length of chain.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
Len,
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I think you are on to something. The Acme Rod does look like it is what they used. Not sure what the engineered smallest size would be but I bet a well anchored set of ¾ steel rods would hold a bench top up. Looks like thy have some nuts that would work also. Not quite as easy as buying a kit with instructions but it looks doable. Good idea on the chain tensioner.
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Thanks,
Bob T.
Bob,
I wouldn't use anything less than 3/4" diameter. I would feel more comfortable with 1". But like Dr. McCoy says "I'm a doctor, not a mechanic." You might want to consider a lock or brake on the chain so it doesn't move after you set your height.
Take a look at the Veritas Twin screw vise. The concept is the same only you wouldn't want to disengage the chain. I would also build a mockup with 2x4s so you can play with the hardware first.
Good luck!Len
"You cannot antagonize and influence at the same time. " J. S. Knox
Len,
Y'know, that sounds just like the adjustment on my thickness planer.Chris @ http://www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
Chris,
It probably is. Although my planer has single Acme screw in the center with linear guide tubes at four corners. I was taught in Design school most designs are evolutionary not revolutionary. Which leads me to. What if you used a single scaffold leveling jack in the center and guide tubes at the corners?
View ImageLen
"You cannot antagonize and influence at the same time. " J. S. Knox
I keep looking at the cheap hydraulic motorcycle lifts and wonder if they could be rigged to lift a bench. Maybe to make the bench more stable, the legs would have pins in them every inch or two that could be inserted when the right height was reached and the hydraulic pressure released. Wondered if the camper/trailer struts would work as bench legs. On the other hand there might advantages to go this route instead.
http://www.adjustabench.com/
Man, this is proof that great minds do think alike!
I've been thinking for years about something like what you suggested - an assembly table with a center jack and sliding sleeves for the outside posts. Haven't yet got around to doing it though.
My brilliant idea (feel free to use it if you'd like) would be to use a scissors car jack in the center of the table. That way you could do the cranking without having to crawl on your belly like a reptile reaching underneath the table. And a little jack like that is inexpensive and would have plenty of weight capacity.
For the sleeves on the posts, I was thinking of one size of steel pipe fitting over a smaller size. Maybe square tubing rather than round?
And, as another poster suggested, it would be a good idea to drill holes into the smaller pipe at increments of an inch or so. Then you could jack the table up a little past where you wanted it, insert pins in the four posts, and let the jack down a bit so the weight of the table would rest on the pins and not the jack. That would make it pretty stable.
Also, in answer to another poster's comment about hydraulic lifting carts, I have one and use it all the time. He queried about one used for motorcycles, but the one I have is quite a bit lighter. It's also probably less stable, but is very useful anyway. You can jack your projects up and down to work on different parts of it (top, base, drawers). I also use it to roll lumber from one part of the shop to another, and for finishing, where I can jack something up to a convenient working height and also spin it around on its casters to put it in the best light. For a hundred bucks, it's one valuable tool.
The hydraulic lift cart has also come in handy when I've ordered a heavy tool and had it delivered via truck. The tabletop jacks up to within a foot of the truck bed and the driver and I can just slide the tool onto it. After letting the table back down and signing the delivery papers, I trundle the tool off to my shop and start attacking the cosmoline.
Zolton If you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
You mean tubing like this?
http://www.alliedtube.com/steel-tube-pipe/mechanical-tubing/square-fit-telescopic.asp
Mcmaster carries it and it isn't expensive. They even have the locking pins. The only issue I see with a center lift (either your method or mine) is if the top isn't balanced then it will bind going up or down.
I've been looking at several types of lifts but to solve my storage problems. This is the one I found that would best suit me.
View ImageThe company is called Loft-It.
http://www.loft-it.com/index.asp
I figured that I could put either tools that I didn't use often on the top and the ones I used regularly on the bottom.
I use the hydraulic carts to maneuver items from one point to another as well. Yes, great minds do think alike.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
Len,
Hey, thanks for the link to the telescoping tubing from McMasters. I didn't know that stuff existed and was going to try to slap together my own.
You're right that if the weight of the top isn't centered there would be the possibility of binding in the tubing sleeves. It might be worse with the size of top I was considering - 4 x 8 feet.
So, I'm still not past that design conundrum yet. But that telescoping tubing might just be the thing that gets me going on this project. Thanks for responding..
ZoltonIf you see a possum running around in here, kill it. It's not a pet. - Jackie Moon
Your welcome. I use to sit at my desk and just thumb through the McMaster Carr catalog during lunch. It was almost better than the Sears and JC Penny toy catalogs.
Len
"You cannot antagonize and influence at the same time. " J. S. Knox
McMaster Carr’s web site also has a kit you can add to an existing bench. They call it an<!----><!----><!---->
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Adjustable-Height Hydraulic Retrofit System. <!----><!---->
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They come with four hydraulic-lift cylinders, a hydraulic pump, and tubing. Attach each cylinder to a workbench/table leg then, mount the hydraulic pump under the workbench/table and connect the cylinders and pump with tubing. <!----><!---->
The scissors car jack idea has been used before (what idea hasn't?) though in a simpler application. See "Rolling Lift for a Workbench" on this site.
Jim
Chris,
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I just clicked on the link to your blog. Your bench is looking really good, I like it.
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Bob T.
Bob,
Glad you like the looks of the bench. It's a long ways from completion, though. I've coped a shelf to fit between the legs. Below the shelf will be three or four banks of drawers which are accessible from either side. Then I have to add the vises and bore the bench dog holes. And the must be something else... there always is...Chris @ http://www.flairwoodwork.spaces.live.com
- Success is not the key to happines. Happiness is the key to success. If you love what you are doing, you will be successful. - Albert Schweitzer
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