[CaptRR]

Hello all,

Earlier this year I build one of the buildyourcnc book machines. I always took it at a learning experience, which it was. Also in the humid Virginia weather I have found that the book machine is not aging very well. The other day I was looking at ways to improve it and came to the conclusion that it would be better to build a new one from scratch.

The design I want to use is a joes 4x4. It seems the be the right size, and having the frame made of metal seems like a good idea in retrospect.

However I have some questions.

The big one is, how to cut the 8020 aluminum. As of this point almost everything I have is wood working tools. Can I get these peaces precut to the correct length? Or should I buy a new power tool for my small shop to cut these pieces.?

Finally, I am thinking of going with a rack an pinion drive. I have read that I will lose some accuracy. But is this really that big of a deal? I will be mostly cutting wood, with the occasional aluminum sheet. Right now my current book build is using a hardware store screw, so I imagine the rack and pinion will at least be better than what I am using now.

Thanks

[uspl]

Hi

If you have a drop saw or compound mitre saw that will handle the material size, then no problem. Get an 80T or 100T blade from your supplier to suit, make sure you tell them it is for cutting aluminium. Also get some cutting / lube compound, comes in a wax stick like a giant candle.

My blade is an Irwin that cost me $90AUD and cuts 8020 like butter in my 8" drop saw. Make SURE you clamp the work well and use a smooth clean cut, not stopping or backing off halfway. The swarf is like fine snow so I put a stocking over the motor housing to keep it out, wear eye and breathing protections as well, if you think sawdust is bad for your lungs try fine aluminium.

I am also starting a new 8020 build, see my thread at http://www.cnczone.com/forums/t-slot..._build_oz.html

Good luck

[ger21]

You can also cut the aluminum on a table saw, ideally with a sliding cutoff sled.
As mentioned above, you want a non ferrous blade, but a high tooth triple chip blade (for laminates) will work well too.

[uspl]

Yes you could but the swarf problem is even worse on a table saw. You will need a very good extraction setup if you don't want to kill your saw real fast.

[ger21]

I've seen aluminum cut for years on table saws with marginal dust collection, and no problems.

[CNC-Joe]

Another option is to purchase an inexpensive metal cutting bandsaw.
I purchased mine for $150 on sale, and use it for everything.

The 8020 that I purchased for my 4x4 Hybrid build (still haven't gotten around to building it...) was cut to approximate length by the supplier (( 8020 Salvage). The 4x4 Hybrid is very forgiving - you can have the 8020 parts longer than necessary -and it will be just fine.

[CaptRR]

I live in constant fear of my table saw since i had a kickback a few years back, so I don't think I will be trying to cut metal on that death trap. The miter saw is an idea, but the one I have is not a compound miter saw, so I am not sure that would work either.

Looks like I am going to have to find bandsaw, though I hate to buy something I will most likely only use one time.

[ger21]

You don't need a compound miter saw, just a regular one will do. A compound miter saw just cuts 2 angles at once, which you shouldn't need to do.
I have a 12" dewalt non compound miter saw, and have cut plenty of aluminum with it. But I still prefer the table saw for accuracy.

[RossMosh]

I have to ask, why not spend the couple of dollars and get the extrusion cut to length?

[CaptRR]

I have to ask, why not spend the couple of dollars and get the extrusion cut to length?

Will the companies that sell the extrusion cut it to the exact length I need? I was under the impression they only sell lengths that are close, not exact.

[RossMosh]

Will the companies that sell the extrusion cut it to the exact length I need? I was under the impression they only sell lengths that are close, not exact.

I'm not sure if 8020 will cut garage sale items on eBay, but if you order "new" extrusion from 8020 or a distributor they will absolutely cut to length. Some places charge a good bit of money for the cuts ($4-5) but in the end if you only need 3 cuts, it's worth the $15. Automations4less.com sells 8020 and does not charge for the cut. The biggest benefit of them cutting is their accuracy. I believe 8020 requires any distributor to purchase a specific saw for cutting their product. It allows for ultra precise cutting.

[CaptRR]

I'm not sure if 8020 will cut garage sale items on eBay, but if you order "new" extrusion from 8020 or a distributor they will absolutely cut to length. Some places charge a good bit of money for the cuts ($4-5) but in the end if you only need 3 cuts, it's worth the $15. Automations4less.com sells 8020 and does not charge for the cut. The biggest benefit of them cutting is their accuracy. I believe 8020 requires any distributor to purchase a specific saw for cutting their product. It allows for ultra precise cutting.

I don't mind buying it new. I figure, when all is said and done, its going to be expensive anyway, so why not buy from someone trustworthy, and if they can cut it for me, all the better.

[nellaac]

8020 says: "You can cut the extrusion yourself with a radial arm saw, cut-off saw, table saw, or other circular saw using a multi-chip, carbide tipped metal-cutting blade. WD-40 or a metal cutting oil should be used to lubricate the blade to avoid burring of the saw cut edge."

[Chrom]

Having just finished my 4x4 build I would ask why you would need to cut the 8020? Most of us just buy the 3 sticks at 72" and the plans call to use them in whole not cut. You do have to cut the R&P rack and the angle iron (or you can get that cut to length).

[CaptRR]

Having just finished my 4x4 build I would ask why you would need to cut the 8020? Most of us just buy the 3 sticks at 72" and the plans call to use them in whole not cut. You do have to cut the R&P rack and the angle iron (or you can get that cut to length).

Just found that out myself, was able to order the 72" 8020 without any problems. I think for the unistrut, I will use a grinder with a cut off blade.

[uspl]

Most of us just buy the 3 sticks at 72"

From personal experience, the 8020 scene in Australia is very different to the USA. Extremely limited suppliers that will supply in 6 metre lengths only, cutting charges of $4-$6 depending on how many cuts.

My proposed build is coming in anywhere from $1000 to $1400 just for the 8020 stock, add another $800 for motors and cards plus $1000 for bearings and ball screws.

[Chrom]

I found a portable bandsaw from Harbor Freight to be invaluable during the entire project. I used it to cut the unitstrut, all of the all thread, and anything else I would normally use a hacksaw on. I got it using a coupon so I walked out of there with it for $59.

[CNC-Joe]

Wow- that's crazy high on the 8020 prices.. I got mine off of 8020 salvage on Ebay for a lot less - like $200-$300 (can't remember exactly)... I know prices have gone through the roof.. but that just seems crazy.

The stuff I got was used - but you sure can't tell that its used... looks almost new.. and straight as an arrow.