Home made Drum Sander

[Mountaincraft]

More Progress...

Worked on this over the last two days.. Lot's of cutting, drilling, grinding, welding, grinding, cutting, welding, drilling, repairing threads,etc... Woke up this morning feeling like a truck hit me.. LOL

Anyways, the bottom end (the hard part) is almost finished... I need to add a couple links to the chain, adjust everything and tack the lead screw nuts in place.. Need to make the lead screw positioners on top.. either out of hardwood or cutting board... Will probably design them tonight and cut them on the CNC tomorrow... Then I need to either buy or make a hand wheel crank for the lift...

Beyond that, it's a matter of talking to tech support at a couple sanding belt suppliers to get some input, and then taking the feedbelt shafts to a local machinist to have them shaped so that the belt doesn't walk... Then the top end should go a lot faster... Still need to come up with a drive system for the belt, but if I have to I might just make a hand crank for now to feed material with ....

I'm gonna need to buy a second V belt as the one I bought isn't gonna be long enough.. fortunately, I can use a second belt to make it exactly the length I need...


Very pleased with the amount of force needed to crank the thing... Gonna get even easier once I get everything adjusted and lubricated...

Anyways, it's a beast... But it's much closer to being a 'living/breathing' beast than is was a couple days ago...

[TrickyCNC]

What an interesting contraption you have there!

I hope it works as good as it looks

[LouF]

Mark you have put a lot of work into it can't wait to see it running...


Lou

[Mountaincraft]

What an interesting contraption you have there!

I hope it works as good as it looks

LOL.. Not half as much as I do!

As long as I can get the feedbelt itself to track properly, it's all downhill now...

[Mountaincraft]

Mark you have put a lot of work into it can't wait to see it running...


Lou

Me too.. I'm sick of using my palm sander!

[CarveOne]

That's looking like a real engineering project. Hoping the project turns out to be better than you expected. My DeWalt 12" planer has a chain drive lift mechanism. It works very well.

[adprinter]

More Progress...

Worked on this over the last two days.. Lot's of cutting, drilling, grinding, welding, grinding, cutting, welding, drilling, repairing threads,etc... Woke up this morning feeling like a truck hit me.. LOL

I can relate. I've been working the past four days on extending the X axis on my CNC. Basically, (yet AGAIN) doing a complete disassembly, redesign, and reassembly of the entire machine! Same here, cutting, grinding, welding, drilling, tapping, and I haven't even started on the electrical side yet.
Did you get the tag number of that truck? -I think it passed through McDonough!

[HorridHenry]

Oh wow,you're going to have some fun aligning that chain on each sprocket ain't cha,I mean one sprocket only has to be 1 thread out and its gonna drift the adjoining sprocket/s

[Mountaincraft]

Oh wow,you're going to have some fun aligning that chain on each sprocket ain't cha,I mean one sprocket only has to be 1 thread out and its gonna drift the adjoining sprocket/s

I figured it out, and one sprocket equals .0067 inch of vertical travel, and then that is spread across a minimum of 25" which comes out to .00027" per inch... Add to that that the drum mount on the top end will also be adjustable, and everything is fine tunable with an end wrench or allen wrench...

Furthermore, simply loosening a pair of setscrews on the sprocket and turning the acme screw allows for adjustment without removing the chain to jump a tooth...

If I can get to where I'm precision sanding to the point where 6 thousands across 25" is a problem, I'll be pretty dang excited (How consistent is sandpaper anyways?)... Heck from what I can see, the wood itself changes more than that just between day and night temps... There always seems to be at least a little warping, cupping, twisting going on with temp and humidity changes even with thoroughly dried and planed wood...

They use a very similar method on surface planers....

I'm quite sure that as long as I get the belt tracking issue resolved, I'll be very happy with this things performance for it's intended purposes.. I will have saved a few hundred (or more) dollars over buying one, and it will have custom features included that are simply not available on any retail sander I have seen..

So, one of the two issues I was concerned about has been addressed (how much rotary force was required to lift and lower the table) and has exceeded my expectations, and one remains (belt tracking)..

After that it's all downhill... The top end should be pretty straight forward.. I have pretty much all the materials I need for that already.. And having the CNC to precision cut the parts should make it all go fairly smoothly...

The only remaining design issue I even see is how to extract dust most efficiently without having the fittings in the way and still allow for the quick change drums...... But even that is starting to get nailed down in my head...

[LouF]

Mark, now I know what happen the chain from my old Indian...


Lou

[Mountaincraft]

So, I've designed the lead screw bushings to hold the top end of the lead screws in place..

material around the bushing hole at the end has to be pretty thin.. (.2")... So MDF/hardwood is out..

Worst case, I'll go with aluminum, but I've never machined it yet and really don't want to use any of the scrap I've been accumulating to make gantry supports/transitions for my CNC rig from...

So I looked on line and it seems that Delrin is the hot ticket.. But man, that stuff is pricey... More than aluminum... I don't expect a 'lot' of force to be applied against that edge as most force will be along the sides where I have room to make thicker...

So my question is, how much difference is there between HDPE and Delrin in as far as strength, compression/stretch, wearability (bearing surface), and machinability?

Is it worth wasting my money on a couple cutting boards, or should I bite the bullet on Delrin, Aluminum, or???



For reference, the red part shows a small pocket that will cradle the top of the 1.5" steel tube, while the slot is where a 3/8" bolt and nut will allow adjustability along the length of the steel tube... The round hole is where the 1/2" ACME screw will pass through... The purpose of these bushing blocks is to simply hold the screws vertical..

[TrickyCNC]

Size for Size, I've found Delrin to be cheaper than Ally

I bought a block 4" x 4" x 2" for £4 GBP off of e-bay

Oh, and I have been noticing that a certain poster doesn't have much nice to say about anyones efforts, so I'd take it with a pinch of salt If you think about the alignment of a chain on a pedal bike ... it's not very accurate at all !

Keep up the good work

Rich