Tosh McCaber Posted June 20, 2023 Share Posted June 20, 2023 Quick question- a fellow club member has run out of Spektrum servo arms, and can't locate any from his usual stores. Are there any other manufacturer's arm splines compatible with Spektrum's splines? Quote Link to comment Share on other sites More sharing options...
toto Posted June 20, 2023 Share Posted June 20, 2023 You would like to think the arms would be a universal fit between most manufacturers. Toto 3 Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 20, 2023 Share Posted June 20, 2023 25 minutes ago, Tosh McCaber said: Quick question- a fellow club member has run out of Spektrum servo arms, and can't locate any from his usual stores. Are there any other manufacturer's arm splines compatible with Spektrum's splines? To fit which Spektrum servos? Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted June 20, 2023 Author Share Posted June 20, 2023 Unfortunately there are several differences in splines on servos throughout the manufacturers. Right from the beginning, when there were no splines- just differently sized square pegs! Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 20, 2023 Share Posted June 20, 2023 9 minutes ago, Tosh McCaber said: Unfortunately there are several differences in splines on servos throughout the manufacturers. Right from the beginning, when there were no splines- just differently sized square pegs! As well as different numbers of splines, the shaft diameters vary too. Quote Link to comment Share on other sites More sharing options...
toto Posted June 20, 2023 Share Posted June 20, 2023 I have spektrum ESC's and receivers etc but not their servos. The models I am flying at the moment all came pre fitted but I have been buying JR servos on the recommendation of Kings Lynn models. I have one other type ( and the name escapes me for now ) but you have got me curious now ..... guess what I'll be checking when I get back from holiday. Sorry I couldn't answer. Toto Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted June 20, 2023 Author Share Posted June 20, 2023 He mentioned "full sized" servos. Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 20, 2023 Share Posted June 20, 2023 (edited) Dubro make Spektrum compatible servo arms, might be worth giving Wheelspin Models a call. Or speak to Steve Webb models aka Servo Shop. Edited June 20, 2023 by Shaun Walsh Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted June 20, 2023 Share Posted June 20, 2023 48 minutes ago, toto said: You would like to think the arms would be a universal fit between most manufacturers. Toto Welcome to earth 😉 or more particularly Welcome to RC World. Unfortunately you'd think that, but it's far from the reality - most servo discs and arms are not interchangeable, even within a manufacturer's range, which can contain a large number of different sizes and functions of servos there will be a lot of variation. Between manufacturers there is no real interchangeability, the diameter, number of splines, screw fixing diameter and length are all variable. Once you accumulate a large number of servos from different manufacturers it's quite a task to keep track of the arms, discs and fittings. I use two compartmentalised boxes, one for Futaba one for Hitec for the majority of my servo hardware, but other minority manufacturers like the Parkzone and EFlite servos from Horizon, Tower Pro, Ripmax, Union, Saturn, Graupner, Dynam etc are labelled as best as I can, but still result in searching for exactly the right arm at times. Luckily storage of Durafly servos is easy, the council provide suitable storage containers for those, they are tall, green, with blue, green or brown lids, have big wheels and sit outdoors. 1 Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted June 20, 2023 Author Share Posted June 20, 2023 The servos in question are DS821 Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted June 20, 2023 Share Posted June 20, 2023 7 minutes ago, Tosh McCaber said: The servos in question are DS821 How about these? https://wheelspinmodels.co.uk/i/90366/ Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted June 20, 2023 Share Posted June 20, 2023 According to SMC - JR servo arms should fit. Quote The DS821 is Spektrum standard digital servo design. The servo is the equivalent to the JR DS589 from which it’s based. The servo accepts standard JR output horns and features a new longer-lasting gear train. The servo is a perfect upgrade for sports pilots in small/medium size applications. Not recommended for helicopter use or installations subject to high vibration levels. 1 Quote Link to comment Share on other sites More sharing options...
Jonathan W Posted June 20, 2023 Share Posted June 20, 2023 10 minutes ago, leccyflyer said: According to SMC - JR servo arms should fit. Yes, I have one model with Spektrum A6000 servos (standard size) fitted and these also have 23T JR type splines. Quote Link to comment Share on other sites More sharing options...
Tosh McCaber Posted June 20, 2023 Author Share Posted June 20, 2023 Thanks guys- I'm passing the info on! Quote Link to comment Share on other sites More sharing options...
Guest Posted June 20, 2023 Share Posted June 20, 2023 Tosh Could these be the ones you are looking for ?? Quote Link to comment Share on other sites More sharing options...
Simon Clark Posted June 20, 2023 Share Posted June 20, 2023 Originally Spektrum servos were made by JR. The DS821 is definitely a JR built unit. When Spektrum went away from JR, they kept the original JR spline design. You can still get JR arms from many different places as has already been said. Simon Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted June 20, 2023 Share Posted June 20, 2023 Just to confuse Toto, quite a few ARTF's have handed servos. e.g. one travels in one direction and the other in the opposite direction as it saves a channel or servo reverser! Applications I have come across where this has been done are gear doors, nose wheel steering and flap servos ether just because they can spec or they can't be bothered to design the issue out...guess if you are buying hundreds at a time the servo manufacturer will accommodate the request. Have others come across other applications? Quote Link to comment Share on other sites More sharing options...
toto Posted June 21, 2023 Share Posted June 21, 2023 Mission accomplished Chris ..... I'll need to get ,y head around that but hopefully nothing that's going to effect me any time soon. ..... hopefully. Quote Link to comment Share on other sites More sharing options...
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