Dremel Flexi Drive Attachment .advice Wanted Please.

[dave2176]

The issue I see with your plan is that a lathe does not turn the rpm required for a small grinder. Would you add gearing to speed it up?

 

[Round in circles]

When geared correctly I can get 1500 rpm or so at the chuck on my old lathe , I might be able to get a lot more than that using the old drill press , if I turn up some better bigger & smaller pulleys for it .
Re:- The flexi drive getting hot , I was going to fill the outer sleeve of the flexi drive with a special high speed copper & silicone based light grease mixture to stop the over heating . The drive cable is rated at 6,000 rpm off a " wired in " Dremel .

I was hoping someone had actually measured the thread form & made one , for I don't have a tread gauge above a 12 mm thread . I do not have any UNF , BSF , UNC or Withworth etc . I can eventually work it out by trial & error but standing on the shoulders of giants is a way I'd like to proceed.

I was hoping to make a threaded nozzle that can be fixed up so the flexi lead retaining collar is fixed solid like it is on the Dremel when things are correctly attached. IE replicate the end of a dremel & have it all fitted to an anchored plate .

Lads .... Thanks for the heads up about the Parkhouse grinder with the flexi drive. I purchased one of their cheapie grindstone one end , belt sander the other end a few months ago .
I'm spending my dosh on other more needy ( says He ) things like ..... 52nd birthday presents for my lass ..... She's well into Bonsai and for years has used a cheap & nasty set of specialist Bonsai scissors & cutters . I've just spent £ 134 ( $ 180 USD approx . ) on a he top of the range set of Bonsai two scissors , a pair of long handled Bonsai branch snippers and pair of long handled bonsai wire cutters ( lovely tools to handle as well ) The pocket money has all gone till the next but one blue moon arrives .

I only want to turn the flexi drive to try and engrave 1.5 mm deep on soft metals such as aluminium , brass or copper plus the odd bit of mild steel , so I don't think I'll need the grindstones speed , torque or a massively strong flexi drive .

 

[British Steel]

Hi David, It looks like the collar thread is M19x2.0, the collet thread's 9/32 x 40tpi or 7mm x 40tpi from what I've found with my GoogleNinja skills
9/32 x 40 is a standard watchmaker's collet size, they say...

Dave H. (the other one)

 

[hman]

I've threaded a goodly number of "dogbone" mounts for Dremel tools. Used a ¾"-12 tap for the nose threads.

 

[Round in circles]

I've threaded a goodly number of "dogbone" mounts for Dremel tools. Used a ¾"-12 tap for the nose threads.
View attachment 127281

Whaaaahoooooo !

That's exactly what I'm hoping to make as well as a threaded sleeve to fix to the flexi drive so I can offer the square core up to a chuck .

The 3/4 thread makes sense as it nigh on 19 mm dia ( 19.2 mm ).
I'm guessing that the National spec is the right one as it is an American designed tool made in China or other low cost country , ( It is ...isn't it ????

However I'll make one of each in some scrap aluminium round bar to see which gives the best fit .

This poster now scrabbles around the desk to find his 1943 ( ish) Atlas MOLO , section seven , Threading , page 41 chart three metric charts & page 45 chart seven National Special thread sizes .
Plus a sheet of paper or two to draw out the setting up diagrams on the banjo arm .

Dave H ( The other one ) , thank you too .

I now have something to go with for tomorrow .
Thanks guys .

 

[TOOLMASTER]

air grinder works too ;-)

 

[hman]

The 3/4 thread makes sense as it nigh on 19 mm dia ( 19.2 mm ).
I'm guessing that the National spec is the right one as it is an American designed tool made in China or other low cost country , ( It is ...isn't it ????

However I'll make one of each in some scrap aluminium round bar to see which gives the best fit .

Hmmmm... hadn't thought of that, but it's a definite possibility. I made the Dremel mounts ~2009, and they fit the Dremel XPR400. Newer models may differ. OTOH, Dremel has a pretty large installed base of accessories, many of which attach to the nose. So they might not want to allow too many changes.

... Plus a sheet of paper or two to draw out the setting up diagrams on the banjo arm .

One suggestion for the banjo arm - make it out of ½" stock, so it's a bit thicker than you really need. Then try attaching the Dremel and check its orientation. You can then "time" the body (to make the switch easier to get to, etc.) by skimming off the surface against which the nose stops. 12TPI = .083"/360º, so it's about .010" for a 45º change in orientation.

 

[Round in circles]

I have no hair left to grind , nor a compressor to compress it . Tool master.

Thanks for that John , I've skimmed precision faces before now to get Purrrrrrfect alignnment .

I was letting things run through my mind whilst I slept last night ( some thing I taught myself to do years ago ) and at 06.30 hrs. this morning thought , " Ahhha , As I'm going to use that bit of round bar to get the thread hole in both sizes.. so why not use the best fitting end cut to thickness & use it as an insert in th bar . Then use a grub screw & thread lock to lock it in the best orientation" . It can always be altered if the need ever arose & making the treaded insert on the ally bar in the lathe will be a lot more accurate ( Hopefully ) than me having to go buy a decent tap and stand at the vice to make the thread in a flat bar .

 

[tq60]

If hand difficulty trash the whole idea.

Instead get a pneumatic high speed hand piece at harbor freight.

They are adjustable to about 60KRPM are very smooth and use small amount of air.

Second choice is a dental hand piece or the cord drive types.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[mohamer]

My Dremel flex drive working end is 1/2 inch diameter, it just fits my 1/2 inch boring bar adapter. Should work fine. I have used my Dremel tool a lot to drill tiny holes in stuff. May try it on the lathe.