Purchase used HD3 or new HD4?

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nabullet
Posts: 1
Joined: Tue Sep 26, 2017 3:51 pm

Purchase used HD3 or new HD4?

Post by nabullet »

First let me apologize if I posted this in the incorrect way or location.

Ok, I am so new to this CNC thing I do not even have a machine yet. I do see for sale "slightly" used HD3 Sharks for what seems to be fair prices. They come with extras like dust boot, a router, touch plate, etc which are extra $$ if I purchased a new HD4.
I see there is a promo for a free laser, after rebate, on the HD4 at Woodcraft.
My questions are as follows.
1. Should one go with an older machine, if in good condition?
2. What are the major differences between the HD3 and HD4? Asking as the answers might make it a no brain'r.

I would love to hear any thoughts, please.

Also, anyone happen to be in ND and more specifically near Minot? I would love to see one in action. I have a couple of project ideas and would love to know if I could do it on one of these machines.

Again, my apologize and thank you for your time.
Na.

Rando
Posts: 757
Joined: Tue Jan 06, 2015 3:24 pm
Location: Boise, ID
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Re: Purchase used HD3 or new HD4?

Post by Rando »

nabullet:

Welcome to the fun times :D.

If you can get the software licenses as well, I'm pretty sure the HD3s had better ($$++) bundled software.

New never has problems created by the first owner. But that first buyer got through the initial nightmares.

So the question is, is the reduction in price worth that tradeoff to you? A really cheap but good used machine might be much better than a new model of a system that has endemic problems. It's a tough call. For me, I'd go with the HD3 if it's your first machine. Machine crashes are something we all deal with when we're learning, so if you're thinking growth long term, a used machine to kill is better than a new machine badly injured ;-). That way when you know how to prevent them, the new machine will appreciate that respect.

If you have to buy the used machine sight-unseen, have them draw x and y axis-lines in a piece of wood, (mount it properly along the axes!) and then run a 2" and a 6" circle profile in a single-pass in some wood. Have them send you a CLEAR, high-resolution picture from DIRECTLY above. Doesn't have to be a deep cut, say 0.050" is fine. Look for flat parts in the X or Y axis where it should be a smooth circular arc. If you see any flats, that indicates backlash in that axis, which means it's aging and may show issues correctly reproducing parts because of that backlash. It can also indicate a machine that was treated less-than-gingerly. Have them use a 90-degree v-bit if possible, as the flats might be more visible. Don't be fooled by variations in the line width, however, since that's going to be down to surface-height imperfections in the wood, which are typically greater in height than issues you'll see with the machine.

Cheers, and let us know what you go with. Looking forward to hearing about cool ideas brought to fruition :D.

Regards,

Thom
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

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