Thread: Alternative to Air Pencil Grinder

Originally Posted by Abratool

Hello fellow air tool users.
I purchased one of those small $30 air tools to use as a toolpost grinder with some limited success, due to its lacking 1/8" dia collet & spindle runout.
Had a 20000 rpm quality USA Air Die Grinder so made up a toolpost set up for it, to use in the Hercus 260 lathe.
Here are some photos. Also used the "Soba" Boring Head for the first time on the Mill.
This small boring head did a great job & was a pleasure to use, after some resharpening of the HSS cutter supplied. Purchased it from Chronus out of England, from memory.
The USA Die Grinder has both 1/4" & 1/8" dia collets that run true (within a couple of thou)
So very pleased with results. The holder for the Die Grinder is a fast set up in the toolpost of the lathe for both internal & milling sharpener grinding.
regards
Bruce

ps More photos to follow

Ingenious bit of clamping there Bruce. I like it.

Does the Dynabrade come with such a long spindle extension or is that an adapter in the grinder's chuck? And how long is the Soba body from the base of the 12mm arbor, if mounted, to the face of the slide? I'm not a big fan of sub continental stuff but that head could be a space saver. Some German Ebayers sell them, I could pretend it was German.

BT

Originally Posted by Anorak Bob

Ingenious bit of clamping there Bruce. I like it.

Does the Dynabrade come with such a long spindle extension or is that an adapter in the grinder's chuck? And how long is the Soba body from the base of the 12mm arbor, if mounted, to the face of the slide? I'm not a big fan of sub continental stuff but that head could be a space saver. Some German Ebayers sell them, I could pretend it was German.

BT

Bob
Thanks for the interest, I was pleased to get an enquiry.
The Dynabrade Die Grinder is not as standard, I recall fitting the extended spindle from some other machine, however they do have a large range of machines & selections available. This one spins at 20,000 rpm & is about 1/3rd to 1/2 HP.... plenty of grunt. A quality tool.
The Boring Head, Soba body from the base to the 12mm (actually 1/2" dia arbor) is 1 13/16" One of the reasons I purchased it was because of its compactness. I needed every bit of space on the Hercus O MIll, as you know the Hercus is limited with its vertical space.
The Soba as supplied comes with a 2mt & 3 mt & the 1/2" arbor & a few cutters in HSS. The cutters as supplied are useless, until reground with some back rake, (like the boring bars used in the lathe) Then all goes well.
I chose an Imperial & the graduations worked out very well, repeatable. I must say like all boring tools with overhang there is a little "spring" & the last cut of a few thou is needed, to bore to a true dimension. I finished at 1.375" dia spot on, so pleased with that.
I was trying to keep up with your drawing, did it the conventional way on the board with the old fashioned drawing machine, I like to draw things up before going ahead with the job.
Even so, I did stuff up a dimension & had to make the component twice. Mistakes happen !
The photo was not clear, still learning with the "Coolpix"
regards
Bruce

Originally Posted by Abratool

Bob
Thanks for the interest, I was pleased to get an enquiry.
The Dynabrade Die Grinder is not as standard, I recall fitting the extended spindle from some other machine, however they do have a large range of machines & selections available. This one spins at 20,000 rpm & is about 1/3rd to 1/2 HP.... plenty of grunt. A quality tool.
The Boring Head, Soba body from the base to the 12mm (actually 1/2" dia arbor) is 1 13/16" One of the reasons I purchased it was because of its compactness. I needed every bit of space on the Hercus O MIll, as you know the Hercus is limited with its vertical space.
The Soba as supplied comes with a 2mt & 3 mt & the 1/2" arbor & a few cutters in HSS. The cutters as supplied are useless, until reground with some back rake, (like the boring bars used in the lathe) Then all goes well.
I chose an Imperial & the graduations worked out very well, repeatable. I must say like all boring tools with overhang there is a little "spring" & the last cut of a few thou is needed, to bore to a true dimension. I finished at 1.375" dia spot on, so pleased with that.
I was trying to keep up with your drawing, did it the conventional way on the board with the old fashioned drawing machine, I like to draw things up before going ahead with the job.
Even so, I did stuff up a dimension & had to make the component twice. Mistakes happen !
The photo was not clear, still learning with the "Coolpix"
regards
Bruce

The only criticism I can make of your drawing is the photo you took of it. I like the right hand lean of the lettering. A couple of the old bastards I work with print the same way as opposed to the rest of them that either print vertically or can't print at all! The Soba box says 12m. I'm wondering if they slipped an imperial arbor in because you purchased an imperial head. I take it a metric head is an option??

As far as the interest goes, you knew I'd be interested. I wouldn't leave you hanging there Bruce.

BT

Nice work Bruce.
I like the style of your holder, i take it you just use the toolpost screws to clamp the grinder in place?

I still haven't bought one of those little grinders, i have been thinking that a 1/4 one might be more handy on the lathe. For workshop use though i do miss my dremel.

Cheers,
Ew

Originally Posted by Anorak Bob

The only criticism I can make of your drawing is the photo you took of it. I like the right hand lean of the lettering. A couple of the old bastards I work with print the same way as opposed to the rest of them that either print vertically or can't print at all! The Soba box says 12m. I'm wondering if they slipped an imperial arbor in because you purchased an imperial head. I take it a metric head is an option??

As far as the interest goes, you knew I'd be interested. I wouldn't leave you hanging there Bruce.

BT

Bob
Must say I never noticed the lettering has a lean to the right, thanks for that, got to keep up with a bit more drawing practice.
I will try & take a better photo in the morning.
The Soba Boring Head does come in either Imperial or Metric, naturally I chose Imperial.The Imperial is part no 171109 & the Metric is part no 171110
Thanks for your interest, just had the feeling you had not been in your workshop lately.
Bruce

I'm always taking an interest in your work Bruce, It's even in imperial which means I can understand it.

Phil

Hi Bruce,

I haven't looked at the website yet, do you mind saying how much the boring head kit was?

Also, when you use coolant on your mill, is it pump fed or do you pour it manually on?

Where do you get your metal stock from?

Nice work too.

Ben.

Originally Posted by Ueee

Nice work Bruce.
I like the style of your holder, i take it you just use the toolpost screws to clamp the grinder in place?

I still haven't bought one of those little grinders, i have been thinking that a 1/4 one might be more handy on the lathe. For workshop use though i do miss my dremel.

Cheers,
Ew

Ewan
Yes the Die Grinder is made secure by the toolpost screws. The holder is bored to 1.375" dia exact & the mating section on the Die Grinder is 1.374" dia. So it doesnt take much to lock it in place. Its a no fuss arrangement & fast to set up & dismantle.
Its made so that its on centre height of the lathe.
However when sharpening end mills I use some packing under the holder to raise it by about.070" this provides a rake angle of approx 5 degrees.
Ground a whole bunch of end mills yesterday in a short period of time, happy with results.
Bruce

Originally Posted by bwal74

Hi Bruce,

I haven't looked at the website yet, do you mind saying how much the boring head kit was?

Also, when you use coolant on your mill, is it pump fed or do you pour it manually on?

Where do you get your metal stock from?

Nice work too.

Ben.

Ben
I could not recall the price however just looked up Chronos UK & the Soba boring heads in kit are 62 pounds say about $85 they are out of stock at the moment.
When using coolant on the mill I use a Hercus drip can (off the lathe) if its a horizontal heavy cutting job, however most times I just use a squirt bottle of soluble oil (high oil to water ratio) to keep fingers well away from cutter.
Most small end milling jobs, an oil can with straight cutting oil in it. The straight oil fumes a bit but seems to hang on & surround the end mill.
I dont believe one needs a coolant pump for a small mill like the Hercus O Model.
Likewise on my Hercus lathe for years I used a coolant pump but moved it across to the Surface Grinder & just use the above system, for drilling, turning etc.. Tapped holes seem to respond well to "Tap Magic Lubricant"
It seems I use bits & pieces of old offcut steel but when I do purchase, get it from "Edcon Steel Validiction rd Kings Park, near Seven Hills NSW.
For turning work I like 1214 free machining steel, great stuff to machine.
For something a bit tougher 1020 bright steel.
For items requiring heat treatment (through hardening, & tempering, steels) Silver Steel is great its a high carbon variety known in the USA as "Drill Rod" It comes precision ground on the outside dia.
Also use "Cherry Red" powder for case hardening the lower carbon steels, when needed.
Used some "Cherry Red" yesterday on a couple of jobs with good results.
regards
Bruce