Making a flex shaft...

[Orph3ous]

My old Dremel 3000 burnt itself out. I have 2 cheap rotary tools that I'm using at the moment, and the one I use most is getting noisy bearings.

So I started looking at saving up for a flex drive... Foredom SR's here in Australia (where we use 220v/240v appliances) go for around $500+, which is way above my piggy bank limit.
The cheaper ones from the US and UK aren't so cheap when you add $50 - $80 in shipping costs, plus the cost of a 240 to 110v transformer...
I can get one out of China for $150, but I'm betting that they're not quite legit at that price.
So I got to thinking, surely there must be a suitable tool or appliance that I could dissect for it's motor?
I'm fairly sure I can make a housing and fit a foot pedal and flexible shaft to it.
Has anyone seen it done or tried it themselves?

Sent from my Redmi Note 3 using Tapatalk

[Dennis]

No record of it on the forum, although members sometimes get bequeathed pendant drills that no longer work.
If you are on a budget, you might read all this:
http://www.cooksongold.com/forum/showthread.php?t=9135
Dennis.

[Orph3ous]

Interesting read Dennis! Thanks for the link. After taking apart the dremel 3000 series I'm totally underwhelmed with the design of them. The switches are nothing more than an adapted light dimmer and the bearings are cr@p!
I'm off to find a vacuum cleaner today to butcher for it's motor =P

Sent from my Redmi Note 3 using Tapatalk

[Orph3ous]

After burning out several cheap rotary tools and not so cheap Dremels, I decided to have a go at building my own pendant motor (flex shaft).

I read that the Foredom SR series motors run at around 15,000rpm full speed, and after a bit of research I concluded that it must be a universal motor inside. Universal motors can run on either DC or AC power and are used in many common household appliances.

So I figured that I just needed a motor with enough rpm and torque so it doesn't slow down when putting resistance on the handpiece.

It turned out that vacuum cleaners also use universal motors and run at similar rpms.

After a bit of hunting around I found an old (late 90's) Dyson DC01 upright vacuum cleaner for $10 at the local recycling shop and took a gamble on it. It seemed to run fine with no sparks from the carbon brushes, and looked like it was thrown out due to a broken drive belt.

The motor itself is an Ametek brand, made in Italy and it still has plenty of life left in the brushes. I'm hoping it will last another 20 years!

It's important to keep the vacuum impeller fan on the motor as it provides cooling to the copper windings, and as the shaft nut is left hand thread the motor shouldn't be run in reverse without modification to secure it. Maybe a split pin through the retaining nut might help, but I didn't bother.

The ABS plastic motor housing was trimmed down and I glued a household power point box to it, which I then fit a 20A switch and variable speed controller into.

I cut the tip off the vacuum's cyclone funnel and mounted it to the output shaft side of the housing, to fit the flex shaft retaining piece to and added a bit of duct tape to make it a tighter fit.

The inner flex shaft coupling was a perfect fit to the motor shaft so it screwed straight on.

Packing shims and modified brackets were bolted to the top of the motor housing for the shackles to go through so I can hang the motor on my bench.

I modified a foot pedal control from an old sewing machine so it now switches power on and off.

It's not pretty, but it turned out to be a pretty sturdy and relatively inexpensive flex shaft.

Approximate costs in Australian dollars:

Vacuum cleaner - $10
Inner and outer flex shaft - $18
Plastic retainer housing - $4
Shims, brackets, shackles and bolts - $12
Handpiece - $20
Foot pedal - $2
Power box, speed control & switch - $22

Most of the flex drive parts were bought online through Aliexpress, but now I know that it all fits together I'll probably replace them with genuine Foredom parts once they wear out.

So for $88 and a few hours work I now have a decent motor with working flex drive attachments, which is cheaper than a Chinese made Foredom clone. https://uploads.tapatalk-cdn.com/20190410/adacafe28a2e8d6a67474afd277d7109.jpghttps://uploads.tapatalk-cdn.com/20190410/a9cf6a13a2cc251915e671bd743c44a2.jpghttps://uploads.tapatalk-cdn.com/20190410/31c56cda24c7d506e09f83c3581ec12f.jpghttps://uploads.tapatalk-cdn.com/20190410/966f81bc53a6c51782161e536ff466ab.jpg

Sent from my Redmi Note 3 using Tapatalk