Tool Post Grinder

[NickG]

Stew,

This is coming along really nicely. Great pics and nice write up too.

Nick

[sbwhart]

Thanks Nick

I'm quite enjoying making it: I've had to use quite a few machining techniques you don't use too often.

Cheers

Stew

[CrewCab]

I'm quite enjoying making it 

I can tell  ................ nice going mate    cracking work

CC

[Darren]

Quite a reach on that boring tool Stew, did it chatter any 

[sbwhart]

Hi Darren

No it didn't chatter with the big cuts it gave a nice parallel finish, but I did get some chatter when I was doing the finish cuts taking the spring out of the bar, but having said that the finish was still quite good.

I've used the boring head with those boring bars a number of times and I've always been presently surprised at the result:- they are very easy to get an accurate result with.

I think I got them from RDG.

Cheers

Stew

[spuddevans]

Now to open up the mounting to take the spindle, I could have done this in the four jaw just clamp the two plate together set them up in the four jaw and drill and bore them out to size as a pair, for a grinding spindle this would have got them close enough on the lathe centre height. But I though I'd do it another way that would get thing dead on centre, this is the best way for any of you making a cross hole drilling sub spindle.

That is a really good way of boring the mounting exactly on lathe centre height  , I'll file that away for future reference as I'd like to make a toolpost grinder at some point in the future, thanks Stew 


Tim

[sbwhart]

I decided to clamp the spindle in the mountains with a couple of M6 grub screws I put a 4mm drill down the end of the grub screws and superglued a little slug of brass into for the screw to tighten down onto so it won't mark the spindle.

Then I made the mounting plate for the motor. I used a bit of 1/4" thick ally plate, it was a mater of drilling holes where required along with a bit of filing.

This is it fitted to the motor





It certainly looks the part as for working well yes and no for the lower speed pulley selection it seem to work OK, but when I swap it over to the higher speed pulley selection it slowly turn over and starts to let the smoke out I guess the motor is stalling. It just doesn't have the humf to drive the faster speed, I guess the spindle is to heavy for the motor, I was a bit uncertain about the suitability of this small motor, but small motors with the speed (6000 ish RPM) and the HP just don't seem to be out there.

This what was on the motor I tried



Perhaps some of you chaps who understand these thing can point me in the right direction as regard motor selection.

Cheers

Stew

[bogstandard]

I have only just noticed that all the posts on this topic are from the UK.

What's wrong lads, cat got your tongue or are you all scared to death of this sort of thing?

I think I have shown this link before for the benefit of our US cousins (or anyone else in the UK who doesn't mind getting a cheapo site transformer to give the 110 volts, about 40 squid). Just in case you don't fancy making one.

http://littlemachineshop.com/products/product_category.php?category=-1731696149

Stew, if you come round sometime, we can have a root thru the motors I have, we just might find one that will do the trick. But make it during daylight hours, they are in outside storage boxes.


Bogs

[Darren]

Oh dear Stew, and there's me having just come home with a sewing machine with motor .... 

[NickG]

Stew,

That motor has a max power output of 90w, which isn't very much anyway, and because that max power comes at 6000rpm this means the torque is very low since power is a function of torque and speed. Because you're gearing up even further, you'll need something with quite a high starting torque. But usually that means sacrificing some speed!

Nick

[Joachim Steinke]

Hallo Stew,

this is my very first post here and I’m absolutely not used to publish in English, so have a little mercy with my grammar, its rusty. So I will try to use more pictures and reduce my statements…..ha ha ha…..

Some years ago I began experimenting with sewing machine motors for the same purpose than you, it was really not very satisfying. Cheap okay, but a lot of noise and vibrations too (poor bearings), and the little types up to 90 Watt are too weak for the most of that jobs on the lathe, particular for outer grinding operations with wheels obove 1” diameter.

So, if it has to be a little bit nice, really low vibrating, very compact and silent too what’s about using that type of servo motor:





This is a Nanotec DB42 Brushless DC Servo, 48 V, 150 VA, 6000 rpm, and it makes enough power for using 2” to 3” grinding wheels without problems. The only crux is the need of some special servo motor amplifier and a DC power supply. I use the Maxon DEC 50/5 amplifier and a switching power supply 50 V, 6.8 A.





Normally I use the spindle on my Mini_Bonelle tool and cutter grinder…..





but it always does a good job on the lathe too…..





Otherwise, for the limited purpose of internal grinding with small tools this little spindle with an Escap 36 V, 70 VA DC motor is really sufficient.








The system is very compact and can be convenient used on even small machines in the class of 13” between centers. Every normal DC power supply with a max. out put of 36 V and 2 A is sufficient to run this high precision motor.





Bye, Achim from Germany

P.S. more details can by seen on my web site http://www.metallmodellbau.de , sorry, but only German language there


P.P.S.  oops...got some problems with linking the pictures??

P.P.P.S...problems with pictures are solveld...ha ha ha

[bogstandard]

Stew,

Just been taxing my brain (whats left of it).

I am sure the brown stuff workers will know something about routers.

I bought one once, crippled some brown stuff with it, then duly gave it away.

What I am getting round to is that it had a very compact but super fast powerful motor on it.

It was only a cheapo Black & decker, but the motor was a self contained lift out unit in it's own case, not much larger than the sewing machine one you have already tried.

My neighbour picks them up from the Wednesday morning market car boot sale almost every other week for a couple of squid apiece.


John

[craynerd]

Joachim Steinke  - your English is excellent, don`t worry about that. Just been on your website with a translator and your work is absolutely amazing! I`m new to this hobby but I think your designs, pictures and finished products are some of the best I have seen....

[sbwhart]

Hi Achim

Thank you for showing your grinder and pointing me in the right direction in regards to motor selection.

Had a look through your site, you have made some wonderful bits of machinery  

First class workmanship.  

I'm going to go back to your site and have a closer look at some of the things you've done.

Thanks you for showing

Cheers
 

Stew

[John Hill]

Joachim Steinke, welcome to our group and please do not be concerned at your skills in English.   I presume you learned your English through careful study at school or university  whereas I learned mine from the wife of a shepherd in the mountains of New Zealand and even now 60 years later I would still be like a helpless baby if I tried to speak your language.

I really admire your work and your photography too!

John Bogstandard,  I have a rather nice 1/2hp router (superceded by a bigger one) which is getting measured up for the toolpost.  The router name plate states 27K RPM and I am wondering what spindle speeds I should be allowing for in my design?