Author Topic: How hard is it to machine a 80% lower?  (Read 2240 times)

Offline JP223

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How hard is it to machine a 80% lower?
« on: November 08, 2008, 07:54:20 PM »
I'm new to machine work. I really want to get a AR45. Any info and, tips?

Offline Prototype Services

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Re: How hard is it to machine a 80% lower?
« Reply #1 on: November 08, 2008, 08:19:32 PM »
Buy one from Justin and have Thompson finish it and send to your friendly FFL dealer.

Offline goober

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Re: How hard is it to machine a 80% lower?
« Reply #2 on: November 08, 2008, 08:24:03 PM »
or, if you want to finish it yourself, start reading and saving up for at least a mini mill, or find access to a mill.
read all the AR15 80% and 0% tutorials that are mentioned in other threads on this site (as well as on others), tool up, and start making chips!
but if you've never done any metalworking before be aware you have a steep learning curve to climb. it's doable though, i'm proof  ;D
heatware username: goober

Offline JP223

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Re: How hard is it to machine a 80% lower?
« Reply #3 on: November 09, 2008, 07:23:53 AM »
Thanks for the info. I really want to do it myself. I'm that type of guy! lol What would be a good mill to get? What about books or, websites that can help. Thanks again for the help!!

Offline goober

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Re: How hard is it to machine a 80% lower?
« Reply #4 on: November 09, 2008, 09:10:40 AM »
JP223:
That's the spirit! Just be careful, they're like potato chips and tattoos... Once you do one you won't be able to stop   :o
As far as the mill goes, I would say there are 3 main factors:

1) Interest level: The cliche above notwithstanding, do you plan to just do this one lower, and possibly never do any metalwork again? If so, you may be better off finding someone with a mill that will let you use theirs; this may have the added benefit of some guidance/coaching from the owner if you need it.

2) Shop space available: Assuming you decide to buy a mill, many folks think you should get as much mill as you can manage. This may be limited by the amount of space you have in your shop/garage/basement/whatever, what the access to that space is like (stairs? narrow doors or tight corners? etc.). If you have plenty of space and can deal with getting it in there, a Bridgeport or similar knee mill would be great. They are huge, and heavy, but aside from the hassle of moving it those are very desirable qualities in a mill  :P You may be able to find a used Bridgeport on craig's list or somewhere for less than $1000. If you have less space or access issues, a benchtop type mill may be a better choice. The Industrial Hobbies square column mill is pretty nice but not cheap (~$2400 + shipping). It's about as close as you can get to a Bridgeport on a bench. Yes, that's a HF 44991 mini-mill sitting on the bed of the IH in that pic  ;D If that's still too big, the Sieg X3 or X2 clones from Harbor Freight, Grizzly, or similar are the next step down. They run about $800-1000 for the X3 clone (HF 93885) or $400-500 for the X2 (HF 44991). These are Chinese machines with everything that comes along with such erm, "workmanship"  :P Not the most precision pieces of machinery but they can be quite serviceable. The X2 is the smallest you should consider; the micro-mill is just too small for the work you need to do. Also, square-column machines are generally preferable to round-column mill-drills.
Along with shop space, AC power can be a consideration. Depending on the mill, you may need just 110V, or 220V, or 3-phase, etc. Be sure you can give your chosen mill the juice it needs to run.

3)  Funding: Guess I already covered that in the Space stuff. But you should also consider the tooling you will need: A vise, clamping set, cutting tools (end mills, drill bits, etc.), holders (collets, end mill holders) precision measuring gear (calipers, dial indicators, etc.), parallels, 1-2-3 blocks, etc. You can drop a few hundred to a few thousand on tooling easy. A DRO, if not included with your mill, is a great thing to have and that may cost as much as the mill in some cases (but can be done more cheaply).

Still with me? You can see that if you're just doing this one lower, that AR45 is going to be a very, very expensive carbine  :P
But if you're getting into this as a hobby and the AR45 is just the first of many metalworking projects to come, it may be worth it to you.
Hope this helps.
« Last Edit: November 09, 2008, 09:46:32 AM by goober »
heatware username: goober

Offline JP223

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Re: How hard is it to machine a 80% lower?
« Reply #5 on: November 10, 2008, 06:57:12 PM »
Thanks for all the info! I have been looking at mills for about a week now. I can't wait!!

Offline eightball

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Re: How hard is it to machine a 80% lower?
« Reply #6 on: November 13, 2008, 11:53:22 AM »
If you're good with soldering and would be satisfied with 1 thousandth of an inch accuracy (chinese hall effect scales), you can go with a DRO-350.  Ends up costing around $150 to build, then another $120-150 in chinese scales.  Do NOT get one if you want the precision glass scales because like 20% of scales can work with it and its a crap shoot, waste of money figuring out what works and what doesnt, trust me =(
Anyways you can get a pcb from www.shumatech.com for around $30 shipped and the rest of the parts from Mouser.com,  I would only attempt this project if you have pcb soldering experience.

Offline JP223

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Re: How hard is it to machine a 80% lower?
« Reply #7 on: November 15, 2008, 11:42:35 PM »
Thanks!! I can do that!