CNC design for consideration

[blackburn mark]

Great, I've been looking at ballscrews on zapp and the difference in cost is not really that great. I could easily go with 16mm ballscrews and that just leaves the 16mm-20mm rails on y to sort which shouldn't pose too big a problem. My only question is, can the ballscrews be mounted directly into a flanged bearing with 16mm opening and a shaft coupling at the other end without machining?

most of us buy 1605 screws from china, "linearmotionbearings2008" (ebay) he will machine the ends for you... its worth giving him a shout for a quote

im sure theres a way of mounting without machining, not sure it would be worth the effort though to save £20 ??

[jonbabbz]

That's great thankyou. Agreed for £20 it would be worth getting them machined. I was just referring to zapp who charge £75 for machining. That would add a considerable amount to the build cost.

[blackburn mark]

That's great thankyou. Agreed for £20 it would be worth getting them machined. I was just referring to zapp who charge £75 for machining. That would add a considerable amount to the build cost.

iv no idea what chi (linearmotionbearings2008) charges for machining... i do remember him being nice n cheap and good comms :)... i dont remember delivery taking ages either

it would be silly not to give him a shout and see whats what :)

[John S]

I normally get a quick order from Chi, 7 to 10 days max but the last half dozen orders have generated a VAT plus handling charge from Fedex, usually about £15, not excessive but worth bearing in mind.

You do have to contact him, tell him just what you want and he'll put that exact order up on Ebay and send you the link. If by some chance someone else buys it before you just tell him and he'll list a duplicate order. The guy is 110% reliable.

[Jonathan]

only three screws ?? if you are not using two screws

Yes! Definitely get 2 for the X axis...
Price sounds about right for Chai. I always pay him directly via a paypal invoice as I think he knocks a bit off due to no eBay fees.

I normally get a quick order from Chi, 7 to 10 days max but the last half dozen orders have generated a VAT plus handling charge from Fedex, usually about £15, not excessive but worth bearing in mind.

Customs recently changed the rules - now everything above £18 value stated on the form gets charged. I don't really mind paying the VAT but £10 handling fee is just extortionate. Last time I just tried paying the VAT (£4.08) and not the handling charge (£10)... so far so good!
Expect to pay another £20 or so since it's a reasonable size order.

[John S]

I don't really mind paying the VAT but £10 handling fee is just extortionate. Last time I just tried paying the VAT (£4.08) and not the handling charge (£10)... so far so good!

If you don't want to pay the £10 then nip down to Heathrow and collect them and pay the VAT there.
Let us know how long it takes you and how much petrol / train fare is

[Jonathan]

If you don't want to pay the £10 then nip down to Heathrow and collect them and pay the VAT there.
Let us know how long it takes you and how much petrol / train fare is

I've already paid for shipping to my door, not Heathrow, so the £10 appears to be to send one letter and collect the money. For the most part it will be an automated system so I don't see how it can cost them £10 to do that - they're clearly trying to make a bit of money. The handling charges used to be much less, and before that they were illegal - I'd happily pay £3-4. Even sending the letter via Royal mail doesn't cost that much!

[jonbabbz]

Thanks for all your help guys, really appreciate it. Asked for a quote, so just waiting now.