Using Delrin Rod

[Garry]

I need some help on buildig suspension links out of Delrin. I found a post here and I bought the delrin, revo rod ends and #8-32 threaded rod. I drilled out the delin and put it all together and the studs pull out of the delrin all the time on the rocks. I am drilling the hole the same size as the rod end so its not like it is too big. Should I be tapping the hole, I drill them about 5/8" deep, should I go deeper? Any tips would be great.

[Failedabortion]

I tap the rod end and delrin a few threads to get it started then leave the rest alone to keep the threads from backing out.

What size bit are you using to drill the delrin out?

[oldhippie]

I have never had a rod end pull out (had a couple split out) of my delrin links! I do use 4mm steel studs with revo ends on the lowers but only 3mm on the uppers and I do drill and tap them.

[xirtic]

The links that I sell use the threaded rod thru the entire length of the link....no way to pull the stud out if the entire link is stud. The Delrin is then just a sleeve over the hardened threaded steel rod (4mm of course). Everybody has a prefererred method for links...this is simply mine.

[Garry]

I drill them the same size as the rod end which is 9/64. I think I will tap the delrin and try that. The threaded rod I have is #8-32 fine thread.

[Garry]

xirtic, do you use revo ends, do you know the part# of them?

[xirtic]

Originally Posted by Garry

xirtic, do you use revo ends, do you know the part# of them?

I tell customers to use REVO ENDS...Traxxas Part 5347. Here is a link from Tower Hobbies as reference. (I typically do not buy from them, but MANY people do.)

http://www3.towerhobbies.com/cgi-bin...&I=LXHGB7&P=ML

[team sidewinder]

Originally Posted by xirtic

The links that I sell use the threaded rod thru the entire length of the link....no way to pull the stud out if the entire link is stud. The Delrin is then just a sleeve over the hardened threaded steel rod (4mm of course). Everybody has a prefererred method for links...this is simply mine.

So then can your links be bent for high clearance applications or at least bent a little.
I am using hollow delrin rod from RCbros with 17 degree bent LCC link ends for my lower links on my LNC but would like delrin bent lower links.

[xirtic]

Originally Posted by team sidewinder

So then can your links be bent for high clearance applications or at least bent a little.
I am using hollow delrin rod from RCbros with 17 degree bent LCC link ends for my lower links but would like delrin bent lower links.

Of course. I have my "bent link jig" that I use for this application. I can make any length that you need (2 day lead-time to produce) as long as you specify the eye-to-eye that you require. In an effort to not clutter this thread, we can continue this conversation via PM if you need further information.

[Garry]

I just checked the part # of the ends I got and they are the same. So how deep would you recomend drilling into the delrin? And is the fine thread ok to use or would you use course?

[xirtic]

Originally Posted by Garry

I just checked the part # of the ends I got and they are the same. So how deep would you recomend drilling into the delrin? And is the fine thread ok to use or would you use course?

www.mcmaster.com

I use this part number for my threaded rod: 98861A050

I run full length.....but if I was to drill/tap them in, I would go about 3/8" to 1/2" in. This may seem like a bit much, but I rather have more threads engaged in the material.

[Crawling Calvin]

Tip when working with Delrin is to run a "coated" tap if you can. Say a TiN coated one. I find they stick a lot less and last a ton longer. Mind you for tapping a few links a "bright" (non coated) tap will be ok but I prefer TiN. Also Delrin has a nasty tendency to "clot flutes up" if you aren't careful with a hand tap (straight flutes.) To get around this, back the tap out occasionally and carefully (note safety glasses) blow out the tube with a can of "air" or an air compressor. Tapping it on a table will work also. Repeat and your set

[ThunderVP]

A 9/64" (0.140") drill is a little big for 8-32 threads. Its recommended to use a #29 drill (0.136") or a 3.5mm (0.137") It doesn't seem like much of a size differance but the Revo ends are 3.5mm bore and it sounds like you're not pulling the studs out of the ball ends. Also if you are using a hand drill, it tends to oversize the hole as you drill because of movement when drilling.

[Garry]

I am using a hand drill, so if I get a #29 bit and tap the delrin I should be good to go. And your right they have not pulled out of rod ends. Is 8-32 the right size for these rod ends or should I use something ealse?

[Crawling Calvin]

Originally Posted by Garry

I am using a hand drill, so if I get a #29 bit and tap the delrin I should be good to go. And your right they have not pulled out of rod ends. Is 8-32 the right size for these rod ends or should I use something ealse?

8x32 is "similar" to M4x.7... both are really tough. Just remember that anything can strip out if given enough force, ive had no issues using M4 with Revo ends, I had a few with M3 and stock Axial ends. Not as much material "biting" in

As for taps, McMastercarr has a good selection. Just make sure to get a nice quality HSS (high speed steel) one. Greenfield makes really nice taps from what ive used on plastic

[jetboat]

Ive even used a smaller bit than Thundervp recommended, I would then use an 8-32 tap about 1/2" in and then thread the rod in about 1" or more. As he said, anytime you use a hand drill you will get some wobble and that will enlarge the holes.

Personally I stopped using that style of link though after I snapped a couple on some tough falls. I switched to xirtic style links.