Couplers - Stepper to Acme

[Blu_Rock]

I see that numerous people are using Lovejoy couplers to connect their steppers and ballscrews/acme threads. It looks like people are using the type that has some sort of synthetic spider that sits between the two end fittings of the coupler. What material is the spider made of and does it deteriorate over time and end up causing problems with backlash?

I see that Dumpster (http://www.dumpstercnc.com/couplers.html) has Delrin couplers. Has anyone used this type before?

What is the better option?

[rodm]

I use either aluminum or stainless steel helical couplings. It just depends what I can get on ebay at the time to suit the machine.
My preference is a helical or bellows coupling as they do not have backlash. Dumpster style would be next and then Lovejoy as a last resort.
Invariably there is backlash in lovejoys be it small as there has to be some clearance for the spider coupling to work properly.
This of course in only an opinion and there might be others that find the lovejoys a joy :rolleyes:

[Blu_Rock]

Thanks again Rod. Earlier today, I checked with my local bearing shop and they quoted me about $75 + GST a throw for helical couplers and said that the bellows type would be even more. I will have to keep an eye out on eBay and try and pick up 3 helical at a more resonable price. Last weekend, I checked out the couplers that Jayar sells (cat. no. YG2782, similar in style to the Nojoy coupler) for $15 but they had noticable backlash so I will give them a miss. I am in no hurry so this project may take a while.

[rodm]

CNCFusion have new aluminum helicals for $30 each. I pay between $10 and $20 each on ebay but you have to be patient as they don't come up all that often.

[Greolt]

In defence of Lovejoys. :q

I have used a few of these. They do not exhibit any backlash when new.

The ones I have used are significantly more substantial than the little toys that Jaycar sell.

The plastic/rubber spider is quite a tight fit. They can be difficult to get together they are so snug.

I am sure as they get older this could need the spider replacing. However on my router that is coming up 18 months there is no deterioration.

For me the good part is I can go down the street and buy them for $17 each.

Greg

[Blu_Rock]

Thanks for the advice. Greg, good to know that the Lovejoys are better quality than the Jaycar's. I will also check out CNCFusion's site.

[crocky]

Lovejoys are great :) now if I could just get my Z-Axis talking again :)

[chrisb691]

In defence of Lovejoys. :q

<snip>

For me the good part is I can go down the street and buy them for $17 each.

Greg
Where do you get your lovejoy couplings from Greg?

[Greolt]

I get them from a local engineering supplies, here in Geelong. I have seen then other places in Melbourne.

However we now have a local supplier of helical couplers for a good price,

http://homanndesigns.com/store/index.php?main_page=product_info&products_id=55&zenid=ab58b821a78b79f932a71188d73578b0

I will be getting some of these next time I see Peter.

Greg

[snowyskiesau]

Here are some other suppliers from previous posts by rodm

MS-Motors (http://ms-motor.com)
eBay seller (http://cgi.ebay.com.au/6-ballscrew-encoder-flexible-coupler-coupling-6-35-8-mm_W0QQitemZ250299389314QQihZ015QQcategoryZ42924QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262)

I did contact Peter at homanndesign. (http://homanndesigns.com/store/index.php?main_page=product_info&products_id=55&zenid=ab58b821a78b79f932a71188d73578b0) He advised he could get other sizes in on request. He also said to check the maximum torque rating of the couplers.