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exit44rc · 03-20-2010, 12:24 AM

I began building my new 250se this evening and found that when I installed my JR ds287's on the cyclic that the metal ball link posts won't thread into the servo arms. The ones that came with my JR servos have holes that are too big for them.

What can I do?

Double Barrel · 03-20-2010, 07:35 AM

I think you are pretty stuck there.There is no way to put a nut on the back of the ball.
Is there no other arms supplied with the servo`s? you will have to find out if any other make horns/arms will fit.

Ozz58 · 03-20-2010, 09:35 AM

most of us used the blank disc and made our own hole with a heated up pin. I only had to do this on my tail servo as it was my only JR. You could do the same thing on the cyclic I think. Might want to trim the disc down some after, but with this method you will get 90 degrees real fast.

Good Luck,

Craig

exit44rc · 03-21-2010, 06:18 AM

What is the distance from center of the horn to center of the ball link on the stock servo horns?

Also, it looks like Dubro makes replacement horns for the JR servos. I see that they have a product called "Dubro Servo Arms Standard JR (8)" Part number 674. The holes on that look like they may also be a little large. Has anyone had experience with this product on the t250?

824TSV · 03-21-2010, 06:30 AM

Dubro makes a variety of arms that fit many applications. Take a servo with you to the LHS and a ball and see what fits. I needed longer arms for my Ino-Lab servos and found a set of dubros that work fine. I found the dubros that I used had very small holes for the balls.

exit44rc · 03-22-2010, 06:57 AM

Did you use the long version of the Dubro servo horns (catalog number 671) or the short/standard version (catalog number 674)?

http://www.dubro.com/hobby/ecatalog/dubro/00051.htm

The standard/short version looks like they may have larger holes than the long version.

Looks like the hole size on the horns that come with the JR servos are about 1.5mm. I need something with a hole size of about 1.0mm.

-HV1- · 03-22-2010, 10:47 AM

I had the exact problem, you can either drill a new hole with a # 56 Drill bit in the supplied arms or use the arms you linked to. I bought the long ones and still had to drill them out. I like the ones that came with the JR servo the were much thicker plastic more ridgid. I drilled them and at some point will swap them, my flying is so far very tame so the only thing I am working very hard is my wallet with replacement parts not servo's or servo arms. On a side note did you use the supplied rubber spacers and screws, what a nightmare.

exit44rc · 03-22-2010, 10:51 AM

Yes, I agree on the rubber grommet and inserts. I believe that I will take a knife and cut the back-side of those rubber grommets off so that the servos will mount flush. I'll have to also cut down the brass insert then to the same size.

The way it is now with the rubber grommets on, the servos stick out too far from the frame and when I put any horns on the servos they hit the canopy.

Which stock servo horns did you drill? The round (disc) one or one of the larger cross-shaped ones?

-HV1- · 03-22-2010, 01:08 PM

I used the one that was an X but two were larger and had a funny bend. Mine did not come with a disk. The screws are the big problem with those servo. They are a much larger diameter than the stock ones, On the aile I used the supplied screws and had to drill out the align plastic nut and try to hold it from the back side to tighten it PITA. I got small washers for the other two and that worked great, the 410 mounting screws will fall through the 285 holes but you can mount them without the rubber or brass insert with the same screw all it needs is a washer. I have 4 packs so far all works great.

exit44rc · 03-22-2010, 01:39 PM

Regarding the servo arm: Where did you drill the hole on the servo arm (servo horn) to mount the ball link? Out past the last hole?

-HV1- · 03-22-2010, 02:17 PM

I took the arms from my 410's and laid them over my new arms and used a pin to transfer the distance. Mine flys fine the way it was. If you need the actual distance I can get it for you I am at work right now just let me know.

exit44rc · 03-22-2010, 02:54 PM

Wow, yes! I would greatly appreciate that. Please let me know the distance from center.

Thanks!

824TSV · 03-22-2010, 06:57 PM

I used the long dubro arms(the black ones) and cut off the excess. The holes are smaller on the long arms and I also CA'd the balls on. I used the 3rd hole out from centre which brings the ball out to 12.5mm. The links are really close to 90 degrees.

exit44rc · 03-22-2010, 07:08 PM

Quote:

Originally Posted by 824TSV

I used the long dubro arms(the black ones) and cut off the excess. The holes are smaller on the long arms and I also CA'd the balls on. I used the 3rd hole out from centre which brings the ball out to 12.5mm. The links are really close to 90 degrees.

Is that about the same for all three of your cyclic servos?

03-20-2010, 12:24 AM	#1 (permalink)
exit44rc Registered Users Join Date: Jan 2010	JR servo arms on trex 250 I began building my new 250se this evening and found that when I installed my JR ds287's on the cyclic that the metal ball link posts won't thread into the servo arms. The ones that came with my JR servos have holes that are too big for them. What can I do? __________________ Prôtos 500, Nano CPx

03-21-2010, 06:18 AM	#4 (permalink)
exit44rc Registered Users Thread Starter Join Date: Jan 2010	What is the distance from center of the horn to center of the ball link on the stock servo horns? Also, it looks like Dubro makes replacement horns for the JR servos. I see that they have a product called "Dubro Servo Arms Standard JR (8)" Part number 674. The holes on that look like they may also be a little large. Has anyone had experience with this product on the t250? __________________ Prôtos 500, Nano CPx

03-22-2010, 06:57 AM	#6 (permalink)
exit44rc Registered Users Thread Starter Join Date: Jan 2010	Did you use the long version of the Dubro servo horns (catalog number 671) or the short/standard version (catalog number 674)? http://www.dubro.com/hobby/ecatalog/dubro/00051.htm The standard/short version looks like they may have larger holes than the long version. Looks like the hole size on the horns that come with the JR servos are about 1.5mm. I need something with a hole size of about 1.0mm. __________________ Prôtos 500, Nano CPx

03-22-2010, 10:51 AM	#8 (permalink)
exit44rc Registered Users Thread Starter Join Date: Jan 2010	Yes, I agree on the rubber grommet and inserts. I believe that I will take a knife and cut the back-side of those rubber grommets off so that the servos will mount flush. I'll have to also cut down the brass insert then to the same size. The way it is now with the rubber grommets on, the servos stick out too far from the frame and when I put any horns on the servos they hit the canopy. Which stock servo horns did you drill? The round (disc) one or one of the larger cross-shaped ones? __________________ Prôtos 500, Nano CPx

03-22-2010, 01:39 PM	#10 (permalink)
exit44rc Registered Users Thread Starter Join Date: Jan 2010	Regarding the servo arm: Where did you drill the hole on the servo arm (servo horn) to mount the ball link? Out past the last hole? __________________ Prôtos 500, Nano CPx

03-20-2010, 07:35 AM	#2 (permalink)
Double Barrel Registered Users Join Date: Feb 2010	I think you are pretty stuck there.There is no way to put a nut on the back of the ball. Is there no other arms supplied with the servo`s? you will have to find out if any other make horns/arms will fit.

03-20-2010, 09:35 AM	#3 (permalink)
Ozz58 Registered Users My HF Map location Join Date: Mar 2008 Location: Texas	most of us used the blank disc and made our own hole with a heated up pin. I only had to do this on my tail servo as it was my only JR. You could do the same thing on the cyclic I think. Might want to trim the disc down some after, but with this method you will get 90 degrees real fast. Good Luck, Craig

03-21-2010, 06:30 AM	#5 (permalink)
824TSV Registered Users Join Date: Nov 2009	Dubro makes a variety of arms that fit many applications. Take a servo with you to the LHS and a ball and see what fits. I needed longer arms for my Ino-Lab servos and found a set of dubros that work fine. I found the dubros that I used had very small holes for the balls.

03-22-2010, 10:47 AM	#7 (permalink)
-HV1- Registered Users My HF Map location Join Date: Jan 2010	I had the exact problem, you can either drill a new hole with a # 56 Drill bit in the supplied arms or use the arms you linked to. I bought the long ones and still had to drill them out. I like the ones that came with the JR servo the were much thicker plastic more ridgid. I drilled them and at some point will swap them, my flying is so far very tame so the only thing I am working very hard is my wallet with replacement parts not servo's or servo arms. On a side note did you use the supplied rubber spacers and screws, what a nightmare.

03-22-2010, 01:08 PM	#9 (permalink)
-HV1- Registered Users My HF Map location Join Date: Jan 2010	I used the one that was an X but two were larger and had a funny bend. Mine did not come with a disk. The screws are the big problem with those servo. They are a much larger diameter than the stock ones, On the aile I used the supplied screws and had to drill out the align plastic nut and try to hold it from the back side to tighten it PITA. I got small washers for the other two and that worked great, the 410 mounting screws will fall through the 285 holes but you can mount them without the rubber or brass insert with the same screw all it needs is a washer. I have 4 packs so far all works great.

03-22-2010, 02:17 PM	#11 (permalink)
-HV1- Registered Users My HF Map location Join Date: Jan 2010	I took the arms from my 410's and laid them over my new arms and used a pin to transfer the distance. Mine flys fine the way it was. If you need the actual distance I can get it for you I am at work right now just let me know.

03-22-2010, 02:54 PM	#12 (permalink)
exit44rc Registered Users Thread Starter Join Date: Jan 2010	Wow, yes! I would greatly appreciate that. Please let me know the distance from center. Thanks! __________________ Prôtos 500, Nano CPx

03-22-2010, 06:57 PM	#13 (permalink)
824TSV Registered Users Join Date: Nov 2009	I used the long dubro arms(the black ones) and cut off the excess. The holes are smaller on the long arms and I also CA'd the balls on. I used the 3rd hole out from centre which brings the ball out to 12.5mm. The links are really close to 90 degrees.

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