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13-370 Motor Mount and Park 300 Problem

#1
Hey all,

I'm building my first tri using the bat bone and the 13-370 motor mounts. I got Turnigy Park 300 1380 kv motors and they seem to align nicely with the mounts, however the stock mount screws that come with the motors are not long enough to use with the 13-370 mounts.

Has anyone else encountered this problem? Any recommendations on resolving the issue? Screw size? Safely altering the mounts?

Thanks,
Kelly
 

xuzme720

Dedicated foam bender
Mentor
#2
A 3mm x 5 or 6mm long has been said to work. Just be careful the screws do not hit the motor windings.
 

Johan

Senior Member
#3
A 3mm x 5 or 6mm long has been said to work. Just be careful the screws do not hit the motor windings.
I'll second that. Depending on your motors, you might be able to look how far the bolts enter the housing.
I had the same problem with my 2822 1275kV Turnigy's. I ended up using 6mm m3, but with a 1mm washer, so effectively 5mm.

I did skip the bolt on the hole where the wires are attached, I just couldn't see if the tip of the bolt would touch that (so I only used 3 instead of 4).

Better 3 bolts with locktite (SP?) than 4 with a sorted motor lead :)
 

earthsciteach

Moderator
Moderator
#4
Powder - are you mounting them through the correct side of the x mount? The head of the bolt should recess into the beveled side of the x mount hole and sit flush with the mount surface.
 

Johan

Senior Member
#5
Powder - are you mounting them through the correct side of the x mount? The head of the bolt should recess into the beveled side of the x mount hole and sit flush with the mount surface.
I think the problem is that the 13-370 mounts don't have recessed holes and are thicker than the x mount. So if you put the crews through the 13-370 mount, there is only one thread or less to enter the hole of the motor...
The motors themselves are just as wide / wider than the 13-370 mounts, so using zipties to connect the x mount to the 13-370 mounts is not an option.
 

xuzme720

Dedicated foam bender
Mentor
#6
This has been an issue for many. Since almost all x-mounts have countersunk holes and hardware to match for a flush mount to a fire wall, that same hardware ends up being too short to mount through the delrin. Best bet is to check your vendor of choice for hardware and get some M3 x .5 pitch and a length of 5mm or 6mm, socket head machine screws. I've found the ones I use on Ebay for a few bucks for quantities of 50 or 100. The head type is whatever you like of course, but I like having a captive type fastener like a hex drive so much better than Phillips or <shudder> standard straight slotted(flatheads)!
 

xuzme720

Dedicated foam bender
Mentor
#8
What do you mean? The flush side IS the firewall side. It's the stock hardware attaching the motor to the X-mount that is in question, when you do away with the x-mount and mount the motor directly to the delrin anycopter mount. If you ARE mounting to a firewall using the X-mount, just use the stock hardware...
 

earthsciteach

Moderator
Moderator
#9
The concern is the longer-than-stock bolts damaging motor windings. The recessed side of the x mount would lay against a firewall, or in this case, the booms. I was just asking if Powder was inserting them through the correct side. If they were being inserted through the non-recessed side of the x mount, they may come up short.
 

xuzme720

Dedicated foam bender
Mentor
#10
Oh, I see. I don't think he was using the X-mount at all. Just direct mounting the motor to the anycopter 13-370 mounts...

Did I read the OP wrong? It wouldn't be the first time, that's for sure...
 
#13
Hey Guys,

I appreciate all the advice!

So I've gone at this a couple of ways. My first thought was to countersink the delrin mounts but I was concerned about opening up the holes too much and also getting the positioning wrong. If I had a mill... or even a drill press I might be able to pull it off but alas...

Next I considered attaching the x mount to the firewall and then fixing the x mount to the 13-370 with zip ties. It sort of worked and seemed as though it might be passable but the motor alignment and how secure it would be was questionable so I decided passable wasn't good enough.

So it's looking like the best option is longer screws... all of you have already told me this but I'm a bad listener. I'm currently on a scavenger hunt because I don't want to order them. The smallest I have found so far are M4 screws and that was at home depot. A local obscure hardware expert (my father) directed me to auto parts stores or radio shack since most small screws like these are used in electronics. I haven't made it there yet but I will let y'all know what I find and where I find it.

Thanks,
Kelly
 

xuzme720

Dedicated foam bender
Mentor
#14
The delrin is strong, but not as strong as metal. I wouldn't try to countersink it, you'll just end up with a weak motor mount and well, I don't think I need to tell you how bad that can be...

Radio Shack is probably going to be your best bet for this size of hardware. If you can't get it there, it might be necessary to order it. Flite Test has these, but they are 20mm long and you'd need to cut them to fit. I got these though and they are 6mm, which leaves me room for a washer for added strength. (Probably doesn't need it but it helps me sleep at night...) I actually get a lot of my hardware from them as they have good prices for decent quantities. I think I paid like $4 for 250 M3 nylock nuts, so I have a few extras now! :)
 
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