We use cookies to personalize content, interact with our analytics companies, advertising networks and cooperatives, and demographic companies, provide social media features, and to analyze our traffic. Our social media, advertising and analytics partners may combine it with other information that you’ve provided to them or that they’ve collected from your use of their services. Learn more.
Questioning potential problems - no matter if they are warranted - is not knocking.
From what I’ve read so far, I for one am not very confident that the OP has the mechanical expertise to make a lot of unsubstantiated claims. I mean you ask us for the correct price, your first sentence is about how it will be sold when it hasn’t even been tested, etc. 8mm rods on 1000mm travel seems a bit slim, but what I fear even more is that a test will be considered a success no matter what, because the OP is in it to make some cash rather than getting the product on point first, and making concessions in the process.
I’m sorry if that seems harsh, I’m not an expert on anything myself, just thinking out loud and voicing my concerns.
And if I may add another thing, I think this mod would be way more interesting if it didn’t need new plates. Would it not be possible to engineer a bracket that mounts on the existing plates? I’d maybe consider that, but if I had to take my machine apart once again, i’d just move on before even considering it.
Did you make sure to read through? Because it was tested to an extent. With the real test next week when the plates are ready.
And as for mechanical expertise, im in contact with a cnc expert (You Know Who you are) and an engineer (big brother) (since as you and i pointed out im not one) and they seem to think its fine especially considering the weight category x-carves are in.
(How ever my brother may be biased no matter how many times he helps me… lol)
Most people seem to disagree how ever since you may be right more testing is still under way!
Thanks for your thoughts! This is EXACTLY why i opened this thread! I need to hear both sides!
I didn’t say he wasn’t qualified to produce anything. But I do read between the lines that this is a normal hobbyist guy with no professional expertise in mechanics and engineering. That’s not a bash whatsoever, but Shirley some scepticism as opposed to just taking his word for it in’t that strange, is it? As a fellow non-professional, I was merely thinking out loud and trying to point out potential problems in order to give another perspective. I thought that was the objective of the thread. Guess I am wrong.
Also the fact that the very first ten lines of the original post dealt with how to monetize this, even before there’s a stress-tested prototype was kind of off-putting.
Also one other thing. Someone just pointed out to me that my design is only for 23 not 17.
Anyone see an issue with that?
Is anyone even thinking of using 17?
And should that be as a custom option?
Again I want to have less holes so less machining so less cost.
I don’t know what the X-carve ships with, but I think a lot of users here stem from the ShapeOko days, which had 17s stock. The question is, is it useful do a leadscrew mod before upgrading motors?
I second that. If you find down the road that someone wants it for 17s, you can look into modifying it then. I would keep the number of variables as small as possible/you find reasonable until you have a solid design to work from, then branch out from there.
I say this from experience in developing my own projects - I have to be very careful about “mission creep” in my designs, or they never get done.
Keep up the good work!
As a small business owner here is my take for you @phantomm.
supply the plates and custom parts, let the end user buy the acme screws, couplers and such. This way it reduces your inventory to only the items you create. Then the end user can purchase the rods, couplers…etc for their specific size machine (500/750/1000+) and from a supplier they choose, then you can concentrate on providing the parts for 3/8 screws, or 1/2 screws depending on the application. Keeping things simple on your end will make you much more lean and profitable.
I was hoping to make one really large purchase on rods that everyone can save money.
Yes it’s more headache but it’s also more value to my customer.
The other option is I can drop ship from my source at cost.
I’m really not looking to make money on anything other than the plates.
Other things you will have to consider by offering the screws and such is the added packaging costs. everywhere will be different, however with the plates and such you can send them priority in a prepaid box and have a standard rate for the continental US.
I can understand wanting it to be a one stop shop, as that is ideal. I would continue to consider just supplying the plates because you (nor anyone else) really have no idea at this time as to the number of kits you could sell to recoup the costs of the inventory. You have to generate a profit on all parts or it is not worth it to do. That is just a hard fact of business. At least at first I would do the plates and if in time it is a demand to warrant housing the other parts… then add to your offerings. If in a few months Inventables decides that the next XC will have screws instead of belts… you are stuck with a ton of overtstock you wont get rid of. Minimize risks and maximize your rewards.
Excellent point. But I was considering having my supplier handle all the shipping and handleing of materials and the plates I’ll handle myself.
I’m even going to drive 3 hours one way to pick up the plates to save people on my shipping costs.
Even though, as many have already mentioned, 8mm dia on a 1000mm span is rather small, you can still get away with it as long as you go slow (-er than your critical speed).
According to this chart (source: Zap Automation) your safe max span is 700mm.
According to this chart (source: Thomson BSA) you can reach 500rpms with B style supports @1000mm. In case this is a 2mm lead , 4-start, your theoretical max feed is 4000mm/min (157IPM).
Another risk you are facing at small dia - large length is runout (or even worse bent screws). In practice your max speed will be lower, depending on the quality (straightness) of each piece. This reinforces @BlueLocktite’s point about sticking to the plates.
This is fine as long as you (and your customers) are aware of this and accept this loss for the gain in rigidity. Between the belt and the leadscrew, one system’s advantage is the other’s disadvantage.
EDIT: With a low dia/length ratio you accentuate this disadvantage, with a high one you eliminate it.
My personal comment on the commercial side would be that I’d expect your product to be priced below a C-Beam kit (which includes a 8mm screw plus a guided rail).
