Balsa Machining - Awesome Part Making

[user 30299]

I was working on a new design that was not quite a Minimum Diameter rocket. Decided I needed to go
with some very slim plywood centering rings; Loc 2.6" body tube, Loc 54mm motor tube. I contacted
Bill at Balsa Machining and asked about making the rings with his 1/8" "lite" plywood.

I got them today. They fit like a glove. And he did this without my actual motor and body tube.
They do some nice work at Balsa Machining.

 

[lakeroadster]

I was working on a new design that was not quite a Minimum Diameter rocket. Decided I needed to go
with some very slim plywood centering rings; Loc 2.6" body tube, Loc 54mm motor tube. I contacted
Bill at Balsa Machining and asked about making the rings with his 1/8" "lite" plywood.

I got them today. They fit like a glove. And he did this without my actual motor and body tube.
They do some nice work at Balsa Machining.

View attachment 555549 View attachment 555550

View attachment 555551

That's awesome. And they are a mom and pop shop... literally. Great parts and service, a great place to spend your hard earned hobby dollars.

 

[bad_idea]

Very nice! I didn't know they still did custom work.

 

[neil_w]

Very nice! I didn't know they still did custom work.

I was pretty sure they *didn't*, and am confused by this thread.

(Of course BMS is awesome, but they had pretty clearly stated they weren't doing custom work anymore).

 

[SolarYellow]

I was pretty sure they *didn't*, and am confused by this thread.

(Of course BMS is awesome, but they had pretty clearly stated they weren't doing custom work anymore).

Yup, I asked and they said no.

 

[rharshberger]

I was pretty sure they *didn't*, and am confused by this thread.

(Of course BMS is awesome, but they had pretty clearly stated they weren't doing custom work anymore).

Loc 2.6 is same or nearly identical to BT-80H and the 54mm motor tube is really close if not the same as BT-70 so a stock CR8070W from BMS might work

I was pretty sure they *didn't*, and am confused by this thread.

(Of course BMS is awesome, but they had pretty clearly stated they weren't doing custom work anymore).

The rings probably are not custom at all...

Loc 2.56 is 2.63" ODx 2.56" ID almost exactly the same ID as BT80 at 2.58"

Loc 2.14 aka 54mm motor mount tubing is...2.26" OD and 2.14" ID and BT70H is 2.245 OD

so its conceivable that a BMS CR7080W (ply ring .125" thick) would work (pretty sure it will but dont have any to check with on hand).

 

[user 30299]

Here are pictures of the cap rings they made for me. A perfect fit to the OD of the body tube.

I'll put a small radius on the ring's edge before I finish the build.

And this is a good time to point out the the bell-shaped motor retainer from Giant Leap Rocketry. A nicely made retainer.

 

[jqavins]

Loc 2.56 is 2.63" ODx 2.56" ID almost exactly the same ID as BT80 at 2.58"

Loc 2.14 aka 54mm motor mount tubing is...2.26" OD and 2.14" ID and BT70H is 2.245 OD

so its conceivable that a BMS CR7080W (ply ring .125" thick) would work (pretty sure it will but dont have any to check with on hand).

Here are pictures of the cap rings they made for me. A perfect fit to the OD of the body tube.

So, if a CR7080W fits the ID of the LOC body tube, what off the shelf part matches the OD? It sure looks like custom work to me.

I was pretty sure they *didn't*, and am confused by this thread.

(Of course BMS is awesome, but they had pretty clearly stated they weren't doing custom work anymore).

Yes, that. So if they've resumed doing simple rings like this, I wonder if they've resumed doing cluster rings. I wonder if they've resumed doing nose cones and transitions. A guy can hope, can't he?

EDIT: I just sent the following inquirey to the BMS contact email address:

An online acquaintance of mine recently wrote about getting some odd size centering rings from you, rings that appear to be custom laser cut. He got some centering rings to put a LOC 54 mm MMT into a LOC 2.6" body tube, and also an end cap, so the same ID as the centering rings but slightly larger OD.

Have you returned to doing custom work? If so, is it only for simple rings, or are you doing complex rings and - dare I hope - transitions and nose cones?

RE-EDIT: It bounced.

 

[OC-Patrick]

Very nice! I didn't know they still did custom work.

I wish they did custom parts - I asked a few weeks ago and Bill says they don't. Nonetheless, they have a great assortment of parts and I use them almost exclusively for replacement and parts for scratch-built items.

 

[rharshberger]

So, if a CR7080W fits the ID of the LOC body tube, what off the shelf part matches the OD? It sure looks like custom work to me.

I just pulled both a section of Loc 54mm motor mount tube and a section of BMS T70H and did a apples to apples comparison of the OD of the two.

Loc 54mm OD as measured 2.258" with a motor case inside to prevent egging.

BMS T70H OD as measured 2.256" using a coupler inside the airframe to resist egging.

My OPINION is that this not actually a custom centering but an off the shelf product that BMS already carries the CR7080W, the actual tube diameter differences are so small that the combination of laser cutting tolerances (which should be slightly generous to allow for different brands of tubing) and differences of the tolerances of the tubes themselves. I will also add that OC-patrick's post above indicates that BMS has not had a change in their custom work stance.

 

[teepot]

I'll ask him. I'm going over there tomorrow.

 

[user 30299]

I thought you might like to know that I did not request "custom" rings from BMS. I did
not even use that word. All I asked BMS was if they could make some "slim" rings to fit
that particular motor tube and body tube. Nothing more.

rharshberger has listed all the reasons why these rings are not custom.

There are a number of people that regularly post on TRF that they can make "custom" parts.
You may want to look into their services. I'm sure they would like the opportunity to get
your business.

Just like OC-Patrick, I like using BMS parts for my scratch builds.

BMS makes quality parts. That was the sole purpose of the original posting.

 

[jqavins]

So, if a CR7080W fits the ID of the LOC body tube, what off the shelf part matches the OD? It sure looks like custom work to me.

I just pulled both a section of Loc 54mm motor mount tube and a section of BMS T70H and did a apples to apples comparison of the OD of the two.

Loc 54mm OD as measured 2.258" with a motor case inside to prevent egging.

BMS T70H OD as measured 2.256" using a coupler inside the airframe to resist egging.

My OPINION is that this not actually a custom centering but an off the shelf product that BMS already carries the CR7080W...

It's the two different ring ODs I'm referring to. There are centering rings, off the shelf CR7080Ws, and an end cap, who's ring OD matches the body tube OD. Is there another tube who's ID (the OD of some standard centering ring) matches the OD of the LOC 2.6"?

I will also add that OC-patrick's post above indicates that BMS has not had a change in their custom work stance.

So it's now clear that, if the end cap is custom, it seems to be a one-off exception.