Reduce diameter of shank

[StringJunky]

The shank on this brush is 1/4" (6.35mm) and I want to reduce it to 6mm. Would using a 6mm die be the simplest/cheapest way or would the metal be too hard? It doesn't matter about it having a thread. I have a rotary tool that only takes 6mm bits. I've tried manually grinding one on a grinder but it was a poor job and quite off-centre. I've also tried buying 6mm bits twice but they are 1/4", despite the fact they say they are 6mm.

 

Edited October 25, 2018 by StringJunky

[Ghideon]

I haven't tried on this type of tool but I speculate that the the shank is not too hard otherwise it would crack* easily. I would give the 6mm die a careful try. Then you could use a file to remove the treads if you wish, it is much easier to keep it centered when using the treads as a guide.

*) I once bought cheap drills where shaft was too hard, most of the drills cracked right off close to the end where they fit in the rotary tool.

 

[iNow]

31 minutes ago, StringJunky said:

I've tried manually grinding one on a grinder but it was a poor job and quite off-centre

Grinding was going to be my suggestion, too. Perhaps grabbing an adapter would be a better option?

No idea about the quality of this brand or particular, but to clarify my recommendation, I'm thinking something like this: https://www.amazon.com/TEMO-Keyless-Adaptor-Conventional-MicroSize/dp/B004HAA22U

[DrP]

I was going to suggest a socket adaptor of some kind, but I-Now has beaten me to it - I wouldn't have even thought about grinding it down - if you are able too then why not? I would have thought it would take some time.

I think you can get very cheap sets of those wire brush sets for Dremel and other spinning/grinding hand tools on e-bay pretty cheap. It might be easier to just but a new one with the right diameter shaft.  The ones from China are dirt cheap....  but they could also be the one most likely to quote the sizes in mm but actually send you out an imperial one.
 

 

 

[StringJunky]

7 minutes ago, iNow said:

Grinding was going to be my suggestion, too. Perhaps grabbing an adapter would be a better option?

No idea about the quality of this brand or particular, but to clarify my recommendation, I'm thinking something like this: https://www.amazon.com/TEMO-Keyless-Adaptor-Conventional-MicroSize/dp/B004HAA22U

That's a thought. Cheers.

[iNow]

8 minutes ago, DrP said:

I would have thought it would take some time.

It obviously depends on the material and construction, but I recall being quite surprised at how quickly grinders can chew through otherwise hard substances.

My first experience was cutting through a solid steel gate clasp with an angle grinder... blew me away how fast it melted through that thing... then later this experience was reinforced when sharpening tools with a bench top grinder.

Summarized, it happens pretty quickly and takes far less time than one might think.

[dimreepr]

40 minutes ago, StringJunky said:

The shank on this brush is 1/4" (6.35mm) and I want to reduce it to 6mm. Would using a 6mm die be the simplest/cheapest way or would the metal be too hard? It doesn't matter about it having a thread. I have a rotary tool that only takes 6mm bits. I've tried manually grinding one on a grinder but it was a poor job and quite off-centre. I've also tried buying 6mm bits twice but they are 1/4", despite the fact they say they are 6mm.

 

2

Wouldn't it be easier to buy a bigger chuck?

[StringJunky]

3 minutes ago, DrP said:

I was going to suggest a socket adaptor of some kind, but I-Now has beaten me to it - I wouldn't have even thought about grinding it down - if you are able too then why not? I would have thought it would take some time.

I think you can get very cheap sets of those wire brush sets for Dremel and other spinning/grinding hand tools on e-bay pretty cheap. It might be easier to just but a new one with the right diameter shaft.  The ones from China are dirt cheap....  but they could also be the one most likely to quote the sizes in mm but actually send you out an imperial one.
 

 

 

I''ve got a dremel and max is 3mm. This tool is a 750w die grinder. 

https://www.amazon.com/Anesty-Electric-Straight-Handheld-Grinding/dp/B07BN8CHMQ

 

4 minutes ago, dimreepr said:

Wouldn't it be easier to buy a bigger chuck?

See link for pic.

5 minutes ago, iNow said:

It obviously depends on the material and construction, but I recall being quite surprised at how quickly grinders can chew through otherwise hard substances.

My first experience was cutting through a solid steel gate clasp with an angle grinder... blew me away how fast it melted through that thing... then later this experience was reinforced when sharpening tools with a bench top grinder.

Summarized, it happens pretty quickly and takes far less time than one might think.

I use a brush on an angle grinder but it's a bit too powerful and not as controllable or variable as a die grinder. it's safer as well because it spins perpendicular to your position sobits fly away from you . With an angle grinder it's easy to have it kick back at you.

[dimreepr]

13 minutes ago, StringJunky said:

See link for pic.

Or a smaller tool? grinding seems an expensive option to be accurate enough.

[iNow]

23 minutes ago, StringJunky said:

With an angle grinder it's easy to have it kick back at you.

A couple of months ago, I built a baby swing from scrap wood for my younger child. Bought some chain to hang it from the front porch and decided to use my angle grinder to cut it.

In my infinite brilliance, I failed to clamp the chain down in any way and it quickly spun around the grinder like a helicopter blade and very nearly took my leg off. 

The surge of adrenaline was fun, but I'd rather not have done that. Lesson well learned there.

[dimreepr]

1 minute ago, iNow said:

A couple of months ago, I built a baby swing from scrap wood for my younger child. Bought some chain to hang it from the front porch and decided to use my angle grinder to cut it.

In my infinite brilliance, I failed to clamp the chain down in any way and it quickly spun around the grinder like a helicopter blade and very nearly took my leg off. 

The surge of adrenaline was fun, but I'd rather not have done that. Lesson well learned there.

 

Fell over using a 9" grinder, got a 9" scar to remind me... 

[DrP]

24 minutes ago, StringJunky said:

I''ve got a dremel and max is 3mm

I bought a cheap hand held etching tool - it is similar I think to those dremel things. I bought it for fossil preparation. It can spin a wire brush fitting like your's or wiggle a spike for etching. I CANNOT get any of the tools to stay in the chuck for longer than a few seconds. As tight as I force it with all my finger strength (and I am stronger than I look!  ) I use it for a very shot while before the tool comes loose. Not so bad with the spinning brush because it still spins, but it makes the etcher useless.  Are the more expensive ones any better than my cheapo one? I paid a bit more for one and I get the same problem....  can't get the tool to stay in the chuck. 

Sorry to crash your thread SJ - but do you think I would be better off with a higher end Bosch one or something like that or am I just being a spanner when it comes to fitting the tool into the chuck?

 

 

 

[StringJunky]

1 hour ago, iNow said:

A couple of months ago, I built a baby swing from scrap wood for my younger child. Bought some chain to hang it from the front porch and decided to use my angle grinder to cut it.

In my infinite brilliance, I failed to clamp the chain down in any way and it quickly spun around the grinder like a helicopter blade and very nearly took my leg off. 

The surge of adrenaline was fun, but I'd rather not have done that. Lesson well learned there.

Yep, an angle grinder is all or nothing. First time I put a flat brush on it, that's disc shaped, I wasn't holding it firmly enough and was cleaning the back edge of a metal plate, it kicked, tore a long hole in my jeans with some nice bloody scratches underneath. I'm used to it now but I think it's still too fierce. Awesome rust remover though.

1 hour ago, DrP said:

I bought a cheap hand held etching tool - it is similar I think to those dremel things. I bought it for fossil preparation. It can spin a wire brush fitting like your's or wiggle a spike for etching. I CANNOT get any of the tools to stay in the chuck for longer than a few seconds. As tight as I force it with all my finger strength (and I am stronger than I look!  ) I use it for a very shot while before the tool comes loose. Not so bad with the spinning brush because it still spins, but it makes the etcher useless.  Are the more expensive ones any better than my cheapo one? I paid a bit more for one and I get the same problem....  can't get the tool to stay in the chuck. 

Sorry to crash your thread SJ - but do you think I would be better off with a higher end Bosch one or something like that or am I just being a spanner when it comes to fitting the tool into the chuck?

 

 

 

That die grinder will be far too big and clumsy for your activity. It's about a foot long. Like holding an angle grinder.. You want something a lot slimmer, don't you? Have you thought about taking off the collet section and putting a small chuck on it? Is this too big?:

https://www.ebay.com/itm/220V-240W-Electric-Mini-Die-Drill-Grinder-5-Variable-Speed-Power-Rotary-Tool-New/302803529968?hash=item46807f30f0:g:n-oAAOSwkbdbSBzc:rk:5:pf:0

This holds up to 6mm. I'm going to get one of these. Problem solved.   Cheers guys.

Edited October 25, 2018 by StringJunky

[DrP]

26 minutes ago, StringJunky said:

You want something a lot slimmer, don't you? Have you thought about taking off the collet section and putting a small chuck on it? Is this too big?:

Putting a small chuck on it is an awesome idea that I just never thought of - thanks.

That one in your pic does look a lot chunkier than mine but might work. I will look for a chuck that I can attach...  as long as that doesn't slip out also.  

[StringJunky]

1 minute ago, DrP said:

Putting a small chuck on it is an awesome idea that I just never thought of - thanks.

That one in your pic does look a lot chunkier than mine but might work. I will look for a chuck that I can attach...  as long as that doesn't slip out also.  

If it's still a problem, maybe you could look to lightly knurling or texturising the surface of the shank to help grip.

[iNow]

1 minute ago, StringJunky said:

If it's still a problem, maybe you could look to lightly knurling or texturising the surface of the shank to help grip.

Or, add some tennis racket grip tape. The stuff is amazing and can also be placed on shovels, wheelbarrows, strollers, and just about anything you must grip and control with your hands.

[StringJunky]

1 minute ago, iNow said:

Or, add some tennis racket grip tape. The stuff is amazing and can also be placed on shovels, wheelbarrows, strollers, and just about anything you must grip and control with your hands.

Yes, that should work with a chuck but a collet arrangement hasn't got the gap to accommodate it.

[DrP]

Thanks Guys - I have already used tape to hold it in place   -  I didn't want to admit it in case it was a stupid idea, lol.  The tape does help a lot but it still comes loose after a bit. That racket grip looks like a good idea - similar to the tape idea I had but better - I might try that sometime...  or just get a chuck.  Will be a while before I get round to using it again anyway. Thanks again.

[iNow]

to be clear, I'm not recommending that tape be used to keep parts together or in any way adhesive. it's more about adding grip and comfort for ones hands

[StringJunky]

4 minutes ago, DrP said:

Thanks Guys - I have already used tape to hold it in place   -  I didn't want to admit it in case it was a stupid idea, lol.  The tape does help a lot but it still comes loose after a bit. That racket grip looks like a good idea - similar to the tape idea I had but better - I might try that sometime...  or just get a chuck.  Will be a while before I get round to using it again anyway. Thanks again.

You could super glue the tape on to prevent slipping.

[Sensei]

4 hours ago, StringJunky said:

The shank on this brush is 1/4" (6.35mm) and I want to reduce it to 6mm. Would using a 6mm die be the simplest/cheapest way or would the metal be too hard? It doesn't matter about it having a thread. I have a rotary tool that only takes 6mm bits. I've tried manually grinding one on a grinder but it was a poor job and quite off-centre. I've also tried buying 6mm bits twice but they are 1/4", despite the fact they say they are 6mm.

 

Do you remember you can simply plug it to regular hammer drill, right.. ?

I have one (the cheapest one Dexter Power 810W for $30) which has switch to change direction, button which controls speed of rotation, and it supports up to 8 mm drill bits.

Because speed of rotation is controlled by you, it's more difficult to hurt yourself.

My cheap mini grinder has not control of speed of rotation, so it's much easier to cut yourself with it. It runs at full speed as soon as you press the button.

 

[StringJunky]

1 hour ago, Sensei said:

Do you remember you can simply plug it to regular hammer drill, right.. ?

I have one (the cheapest one Dexter Power 810W for $30) which has switch to change direction, button which controls speed of rotation, and it supports up to 8 mm drill bits.

Because speed of rotation is controlled by you, it's more difficult to hurt yourself.

My cheap mini grinder has not control of speed of rotation, so it's much easier to cut yourself with it. It runs at full speed as soon as you press the button.

 

A standard drill is too slow for serious rust removal and not nice to hold in that configuration. I do have those options with electric and battery drills. Cheers.

[StringJunky]

@DrP I think this arrangement on the right might suit you for fossil cleaning:

[tinkerer]

Simple enough solution: dog-goned certain the wire wheel shank is not very hard, I would simply chuck the first 1/4 inch of it in my lathe, turn the portion between the chuck jaws and wheel down from .250" to .236"; one cut would likely do the job. Then, cut off the 1/4" stub that was chucked in the lathe. 

This should not be such an involved thing, should it? The horse is by now dead.

[StringJunky]

3 hours ago, tinkerer said:

Simple enough solution: dog-goned certain the wire wheel shank is not very hard, I would simply chuck the first 1/4 inch of it in my lathe, turn the portion between the chuck jaws and wheel down from .250" to .236"; one cut would likely do the job. Then, cut off the 1/4" stub that was chucked in the lathe. 

This should not be such an involved thing, should it? The horse is by now dead.

I ended up free hand grinding it on the grinder again. I just took my time. I was rushing first time.