[Mountaincraft]

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

I looked at the delrin lead screw nut on the Z axis of my CNC rig and it is much thinner than what I am doing.. So now I know that if worse comes to worse, delrin 'will' work for me...

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

Where's the 'like' button?

[TrickyCNC]

I looked at the delrin lead screw nut on the Z axis of my CNC rig and it is much thinner than what I am doing.. So now I know that if worse comes to worse, delrin 'will' work for me...

I just bought some to experiment with, because I thought I should !

It seems to be used and recommended a lot, so it seemed like the right thing to do

I'll be making a nut for my new Z 1st. Then maybe some bearing blocks. Housings for some limit switches ... But mainly just 'playing' to see what all the fuss is about .

Rich

[Mountaincraft]

Let me know how the machining goes for you...
bits, feeds, speeds, etc...

[TrickyCNC]

Let me know how the machining goes for you...
bits, feeds, speeds, etc...

HaHa .. I just asked the same question !

http://www.cnczone.com/forums/diy-cn...ng_delrin.html

didn't get any specific answers other than it seems it cuts easy .. anything goes

Rich

[TrickyCNC]

I can add, ...

I cut some on my band saw ... cut's easy
I tried it with a block plane ... cuts easy

I like it so far

just got to find out how strong it is

Rich

[adprinter]

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..

You might try going to a cabinet shop, and pick up a piece of Corian. It machines like wood (sawdust, instead of melted plastic), and it's some pretty strong stuff. Since color shouldn't matter in your application, I'm sure anyone doing a remodeling job with Corian counter tops would probably have some scrap pieces large enough for your use. I mention this, (the color) because it will probably widen your options in finding some.

[Mountaincraft]

I haven't posted on this thread in a while, but I have been working on this slowly but steadily...

I have the motor mounted as well as the drum, and have the quick change system designed in.. I have balanced and turned the drum and it is ready to be sealed and the velcro applied...

Just deciding on what to seal the MDF drum with still.. It spins nice and smooth.. Had some trouble getting the drum balanced using the sand paper glued to a sheet of MDF routine, because the speed at which the drum turned was so high that it set up harmonic 'bouncing' and prevented getting the whole drum smoothed out and balanced.. So I ended up taking it to a machinist friend and had it turned on his metal lathe at a much slower speed..

Unfortunatley, I had taken so much off trying to sand it the other way, that I had to red engineer the support/quick change parts.. Which I was planning on doing anyways because of problems I ran into the first time (pieces not lining up perfectly due to a worn out router bit)...

Sure is ice to have the CNC rig to cut parts though..

Anyways, here are some pictures from about 6 weeks ago, of how I made the drum... All the excess glue was the major problem with the out of balance... On the rest of the drums, I will make them the same way, but just take them to the machinist right from the get go and have them turned to exactly the same diameter as this one...

There were also some issues with the motor mounting, and I'll go into that when I post more pictures later....

Anyways, here's the drum construction....

Oops.. My domain expired.. Just renewed it, so once it's up again, I'll post the pics...

DOH!

[Mountaincraft]

[Mountaincraft]

[LouF]

Mark it looks good your moving right a long with your build thanks for the update.
PS. that sure is pretty country up there nice tall trees green every where not like here 98 right now...

Lou

[Mountaincraft]

Mark it looks good your moving right a long with your build thanks for the update.
PS. that sure is pretty country up there nice tall trees green every where not like here 98 right now...

Lou

Well, normally, it's in the 90's this time of year, but we have cool nights which is nice.. But the last few days a system has been moving through and I've actually had to use my fireplace a couple times...

[Mountaincraft]

Here's a few pictures of the machine as it is now....





This is the sanding block I made to try and dress the drum.. but eventually had to have it turned on a lathe anyways...






This is with the table adjusted most of the way up.. I'll be able to set it to sand very thin pieces if necessary...






This is with it adjust about 2/3rds of the way down... I'll be able to sand material up to about 11" thick if necessary.. I'll probably very rarely need that kind of thickness ability, but I wanted it in case I wanted to sand a 'box' or something....

[LouF]

Looks good you put a lot of work into it the part on to is that to feed the material?


Lou

[Mountaincraft]

Here is the drum removed from the sander... as well as a shot showing how the mounts receive it...

it pops in and out even easier then I had hoped.. This is going to work very well.. The hardest part will be making more drums....

There is a 3/8" nut set in a routed recess on the back side of the bearing mount plates.. and a 3/8" bolt is run through the drum mount side panels to lock it in place...

[Mountaincraft]

Here's a shot of the problem I ran into with mounting the motor..

After building everything there wasn't enough room to put the motor where I had originally planned without a bunch more welding, so I relocated it here.. However, the diameter of the motor was such that it required me to set the motor back in from where the pulley needed to be.. meaning I'd need to extend the shaft...

The first picture is my first attempt at this.. Didn't think it would work, but I gave it a shot anyways...







This second picture is the fix, I had the machinist friend make me an extension using a coupling that had a 1/2" NF thread inside that threaded onto the end of the motor shaft.. and then a 5/8" cold rolled steel rod coming out the other side of the coupling and extending through a flange bearing I bought for the purpose.... Then is was just a matter of making a 'mount' for the bearing out of sandwiched MDF mounted to the motor flange (having the CNC made this really clean and easy)..

The motor is mounted using a couple unistrut straps, some strut and gate hinges welded to the frame...

It all works great!

[Mountaincraft]

so besides sealing the drum and installing the velcro... all that is left is to make a bottom that will be attached using the dados in the drum side mounts that can be seen in the pictures, a front and back brace that will go in the recesses that can also be seen in the drum mount side pieces, and a 'box' assembly that will slide down over the top of the thing....

Now the 'plan' is to also have access to the top of the drum, so that I can use it the same way many of you use your home made table top drum sanders.. Not sure if this will be integrated into the first box that goes on top, or into a second one... In any event, it will have T-Slot on the front and back so that a sliding tilt fence can be integrated into it...

I'm also going to have to make a manifold to hook up the vacuum.. The four 2" round holes in the side mounts are for this...

[Mountaincraft]

One thing I'd really appreciate, if any of you guys have the time, is to take a picture of your sanding drum/top on edge (from the end eye line along the length of the drum) so I can get an idea of how much it needs to stick up through the top.. preferably with the drum spinning and also stationary, so I can see how much it 'fluffs up'..

Maybe set a piece of wood across it too (while it's still), so I can get another perspective of how far it protrudes through the top....

Thanks,
Mark

[Mountaincraft]

Once this thing is all up and running and in use, I also have the option of later turning it into a 'dual drum' machine.. There's plenty of room, the drums will already be made and all I will have to do is lengthen the belt and rebuild the MDF end structures and drum box.. This would allow me to medium and fine sand in a single pass....

[Mountaincraft]

Woooo Hoooooo!!!!
:wee:

So, I sealed the drum with several coats of polyuethane a few days ago, sanded it, and let it cure for the time since.. I just got through putting the velcro on, and then some 150 grit sand paper...

Fired it up and tried sanding a scrap of maple with it...Even with the velcro mounted paper it very much works like a precision thickness sander... Man, this thing is gonna be great!

All I have to do is to finish building the drum enclosure, wire up some switches, and then I can use it (manually cranking the feedbelt).. Later I can power up the feedbelt, and get it all tracking nice...

In the meantime, I gotta glue up and turn another drum for the 220 grit paper...

Also scraping up the money to buy a dust collector later this month... Sawdust is really getting to be an issue in the shop....

Looking at THIS ONE

Once I get the shop cleaned out, and the ducting for the collector installed, I can turn my attention to collecting steel and starting the rebuild of the CNC in the shop... The only other piece of equipment that is somewhat 'urgent' is a good bandsaw and resaw fence....

Anyways, here's some more pics... Sure relieved now that I know it's gonna work like I wanted... AWESOME!

[LouF]

Mark,congratulations on your build I am happy it came out the way you wanted Now build one for me...:stickpoke


Lou