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Thickness Drum Sander #3: Tables and Lifting Mechanism

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Blog entry by Vip3r74 posted 07-24-2013 01:01 PM 3605 reads 3 times favorited 15 comments Add to Favorites Watch
« Part 2: Design and Planning Part 3 of Thickness Drum Sander series Part 4: Drum Assembly »

Now for the interesting stuff. I’m not going into detail on the first table design because I feel that the second table design will be more stable. Again I am open to all criticism and advice, that is the only way we learn in life.

One very important fact that I would like to make clear is that the total travel (up and down) of the tables in both design will be 1/2” You will see that there is a vertical row of holes on the 4 legs, they are for 1” increment size changes with a maximum workpiece thickness of 4 3/8”. All that is need is to loosen 4 bolts. So I will be able to finish sand small boxes or other thicker jobs as well.

Design 1.

This works on a back hinge system.

This is the lifting table, it wil be secured to the frame using 4 bolts. The black knob at the front is attached to threaded rod and is for fine adjustment of the top table.

This is the top table and it will be secured to the frame with 2 bolts towards the back for a hinge effect. The front will rest on the lifting mechanism of the bottom table. Both sliding areas of the tables will be 3/4” plywood lined with 1/4” hardboard for smoothness.

Okay, that is it for design 1.

Design 2.

The biggest factor for design 2 was that I want the table to lift back and front together, I’m not very fond of the hinge type lifting. Not to sure why I feel this way, just like the table to stay horizontal.

I kept the main design for the lifting mechanism, just doubled it up.

The last pic is just to show the maximum intend height that I intend to lift the table. The rest of the setting will be done as explained at the top. 1” increment drops with the holes on the frame.

You will see that I have added 4 blocks to the top table, that had to happen otherwise the top table would be floating around on the 2 lifting parts which obviously is not a good idea. The 4 blocks will house 2 bearings each, one at the top and one the bottom. That is also why the frame changed, there will be 4 guide rods for the bearings so that the table can’t float. The only drawback to this for me is that I still cannot look at changing my table to a belt feed system. I’m working on that, “Design 3”. No success yet on that one.

Thanks for watching and the advice, I appreciate all criticism and advice.

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.



15 comments so far

View SPalm's profile

SPalm

4939 posts in 2634 days


#1 posted 07-24-2013 07:51 PM

Interesting. I don’t believe I have seen that four post method before. Kind of cool, if you can align those four posts.

A couple of thoughts (because thoughts are free)

Replace the knob with a crank.

Consider building the top platform as a torsion box. A simple piece of covered ply has a lot of play and twist in it. You certainly have the vertical height for a two inch tall box. Half inch MDF skins and an internal web of MDF all glued up. And cover it with Formica – it is slippery and adds a lot of strength. Making it out of Baltic Birch ply would keep weight down but costs go up.

It seems like you counting on the rods to keep the top level as it is raised and lowered. You can make the vertical bearings longer by going down farther on the leg. The longer they are, the more support they will give. Are you planning on using real linear bearings? These could be a bugger to align the first time. You want to be able to raise or lower the table by just a smidgen and have all four corners stay in sync. The lifter could have a roller in the center.

But then again, these are just initial thoughts,
Steve

-- -- I'm no rocket surgeon

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#2 posted 07-25-2013 07:26 AM

Thank you for the thoughts SPalm, much appreciated. Helps my me to look at the whole thing differently, which is a good thing. I am by no means a pro. Setting up is going to be an issue but I’m sure with patience I will get it right.

Regarding the bearings, I do intend to use real linear bearings. The rods is silversteel rods used in tool & die making. Setting up is going to be an issue but I’m sure with patience I will get it right. The roller idea on the lifters is a good one, it will make the movement a bit smoother.

As for the table, that also sounds good. I do want it to last long so I should do it properly to. I made a quick pic just to make sure I understand what you are saying.

The top pic, is this the type of sandwich you mean I should make?
1/2” MDF sheet
1/2’ MDF Torsion Box that is 1” high
1/2” MDF sheet
So in total it will be 2” high?
Do I add a frame of some other wood, the reason I ask this is that I think I need about an inch box at the bottom for the lifters to work in. Don’t know if that is a must.

Thanks again for your input. :-)

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View SPalm's profile

SPalm

4939 posts in 2634 days


#3 posted 07-25-2013 11:48 AM

Yes, something like that. What ever works for your use. The sides can also be the frame. Just think about a hollow core door and how light and strong it is – the skins can be thinner, but the webbing must be glued strong to both sides. A hardwood frame would be nice.

MDF can be very heavy, but it is know to be a flat surface. Big Box plywood is known to be shaped like a potato chip. Quality ply from a wood store would be the best, but as mentioned, it is expensive.

Glad to hear you are using bearings, else you would have to go through an alignment every time you change the height of the lifter table.

Just thinking about it, those lifters if spun around and put together would be a scissor jack. Don’t know what that has to do with anything, but I just thought it was interesting. :)

Later,
Steve

-- -- I'm no rocket surgeon

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#4 posted 07-25-2013 12:31 PM

Funny that you should mention scissor jack, at one stage I was contemplating using a scissor jack screw for lifting the head unit but quickly realised that it would not work because of the V-belt. I still thinking of other ways to change the height in a different way so that I could put a roller feed system on.

Thanks

Marius

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View TTalma's profile

TTalma

10 posts in 1444 days


#5 posted 07-25-2013 04:25 PM

If you want to use a feed conveyor why not just raise the head up and down. If you plan to use a belt feed for the motor just put the motor on a hinge and it will swing up and down as the drum moves.

You could raise the drum with 4 pieces of threaded rod and bicycle chain, basically how a lot of large planer works.

Also if you are planning on spending the money on linear bearings, 4 of them the size you would need for the table would cost about the same as a purchasing a drum sander.

-- There's only 10 types of people in this world. Those who know binary, and those who don't.

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#6 posted 07-25-2013 08:07 PM

That’s the thing, I already have the bearings. It was supposed to be for a project a friend was doing and he could not use them like he thought he could and they have been lying in he’s storeroom for who knows how long. So when I saw them the other day I inherited them from him. That is why I changed my design. Thanks for the feedback. :-)

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View lew's profile

lew

10164 posts in 2508 days


#7 posted 07-26-2013 01:21 AM

The scissors lift worked pretty good on the sander I made. I opted to have one end of the table hinged and the scissor “jack” lift the other end. I tried to keep things as simple as possible so that calibration- table staying parallel to the drum- was not an overwhelming process.

Later, I added a “handle” to the knob to make turning it easier.

-- Lew- Time traveler. Purveyor of the Universe's finest custom rolling pins.

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#8 posted 07-26-2013 07:00 AM

I have seen a couple of those chain raisers here on LJ’s but I have just not been drawn to it, maybe I should have a second look at it.

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#9 posted 07-26-2013 07:21 AM

Wow Lew, that is awesome looking scissor lift. Looks real solid and deadly acurate! Thanks for showing!

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View hutomthe's profile

hutomthe

1 post in 553 days


#10 posted 07-30-2013 12:42 PM

Hello
Thanks for this information Regarding it.I was wondering how it is work. I have it but didnt know how it is work.
Thanks for sharing this.

Goederenlift
Stapelaars

View Okiewoodturner's profile

Okiewoodturner

5 posts in 507 days


#11 posted 08-07-2013 01:51 AM

Hello everyone,
A new member herre, joined because I read alot of the post on the shopmade drumsanders. I have to say I have made two drum sanders to date. Both were built using a lathe. First one on a Delta 46-460 it worked great. Able to get nice flat rings for my segmented bowls and consistent thickness on thin strips of wood. I sold the lathe and needed another drum sander. Having a 10Er shopsmith sitting in the corner so this became my platform for the 2nd project. While it works ok not as happy as I could be. Most of my frustration admittedly most the issues were of my own making. I wanted a large table to sand longer and larger pieces of straight lumber. I have a jointer and planer so my goal was not to use the sander as a thickness planer. Wanted to be able to again sand long thin strips of wood. My issues were rounded edges on my rings, table twisting with one lift screw. Bought the materials to build the scissor lift in this post.
However always ready for a new challenge wanted to build a DS with electric lift and more importantly an automatic feed. Posted a wanted free treadmill or really cheap on Craigslist. Seems to be lots of people needing their room back. Anyway picked a treadmill up this evening and if the wife doesn’t claim it, will be the base of my next project.
Having read opinions on issues using a treadmill have decided to forge ahead. So after being longwinded my question is: is there any reason to shorten the treadmill bed. After looking it over the thought entered the mass in my head and posed this question. Thinking I can build the stand, drum using a one HP or larger motor to drive the drum. Realize there are probably challenges I haven’t condsidered. Would appreciate any and all thoughts, suggestions, be they postive or negative.
Gotta say I enjoy the site and information concerning alot of subjects.
Steve

View Okiewoodturner's profile

Okiewoodturner

5 posts in 507 days


#12 posted 08-07-2013 01:55 AM

Lew did you hard attach the scissor lift to the bed? I am assuming the what appears to be a spring is to assist in lowering the table. How much lift does this give you?
Thanks for and info.
Steve

View Rick M.'s profile

Rick M.

4508 posts in 1132 days


#13 posted 08-07-2013 09:11 PM

I like design #1 but just to throw another idea in the mix, have you seen the sliding wedges in the Shopnotes drum sander?
http://www.shopnotes.com/plans/thickness-sander/

-- http://thewoodknack.blogspot.com/

View Vip3r74's profile

Vip3r74

65 posts in 562 days


#14 posted 08-08-2013 05:46 AM

It’s definitely a better idea than the single threaded bar in the center like a couple of others I have seen. I still don’t like the idea of supporting only in the middle of the table.
I have been thinking a lot about my plans and it seems like I gonna stick with plan 1. It feels to me like I want to over engineer to much in plan 2 and also 3 that I have not posted.
Sometimes keeping it simple is the best!

-- Create, create, create create. It makes my blood flow. And what better material to use than wood, you can repeat the same object 1000 times and none will look the same in natural form.

View Rick M.'s profile

Rick M.

4508 posts in 1132 days


#15 posted 08-09-2013 05:38 AM

The downside is multiple points of contact requires more precision but you’ve thought this out well and I doubt that will be a problem.

-- http://thewoodknack.blogspot.com/

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