LMS #1275 Tool post grinder- impressions

[S_J_H]

I just picked up one of these tool post grinders from LMS.
http://www.littlemachineshop.com/pro...1275&category=

I have a need for a TPG/drilling head and since I am knee deep with my other projects I did not want to bother with a 100% scratch build. I have already tried the die grinder and dremel thing years ago on the lathe with poor results.
Oldtiffie also has this TPG and I had asked him what his thoughts were.
So having owned a number of import machines and tools I pretty much know what to expect now. I figured it was a assembled kit like most of the cheap import machines.
IMO, yes it is a kit. I had to turn off .1" on the driven pulley to keep proper belt alignment right off the bat. The supplied wheel needed quite a bit of dressing.
It uses simple deep groove bearings and the spindle while made accurate is "rough".
The motor appears to be the same as used in a 7x mini lathe and a uses a similar type of controller.
The motor runs very smooth though as does the belt drive system. 7000rpm is the limit but it would be very easy to make new pulleys to increase the speed some.
The little drill chuck is not to bad. It has about .00125" runout and can get a drill bit to run about as good.

So I installed it on my SB9 , dressed the wheel and tried it out.
It actually works very good with little vibration. Plenty of power and left a good finish.
I will probably modify it a bit with better bearings and possibly make a new spindle with a er11 collet head instead of the tapered end for a 6mm drill chuck.
Steve

[wierdscience]

Not a bad looking unit.It's a good bit bigger than I imagined though,they really should give something for scale in the pictures.

[lazlo]

IMO, yes it is a kit. I had to turn off .1" on the driven pulley to keep proper belt alignment right off the bat. The supplied wheel needed quite a bit of dressing.
It uses simple deep groove bearings and the spindle while made accurate is "rough".

How rough? I've never seem pictures with it actually mounted on the lathe, but that first picture looks a lot like they just mounted a benchtop drill press sideways, like Evan did?

[S_J_H]

Not a bad looking unit.It's a good bit bigger than I imagined though,they really should give something for scale in the pictures.

yeah it's decent sized for my SB. I don't know how the heck you could fit this on a mini lathe.

I don't plan on using it much on the SB. It'll be used mainly on the cnc HBM/Lathe I'm building and will be easier to setup on the T-slot crossfeed table.

ow rough? I've never seem pictures with it actually mounted on the lathe, but that first picture looks a lot like they just mounted a benchtop drill press sideways, like Evan did?

Rough as in soft metal, threads that are still burred, seating taper for the wheel is poorly finished. Typical stuff you know..
Yeah I suppose it does look like that. But nah, nothing drill press like about it. The spindle is small. It only uses 12mmID x28mm OD bearings.
But it all actually works fairly well. Lot's of room for improvement though.

Steve

[lazlo]

Yeah I suppose it does look like that. But nah, nothing drill press like about it. The spindle is small. It only uses 12mmID x28mm OD bearings.

Hard to tell the relative size

You'd have to bore out the bearing pocket to fit angular contacts -- the smallest AC with that bore size is the 7201: 12 x 32mm. A pair would be quite a bit deeper too, but you might be able to use one on each end and (cough) preload the beaings end-to-end with the spindle shaft, like the Dumore spindle does.

[S_J_H]

another view of it on the lathe-

I very quickly removed .01" off the diameter of some 1/2" OD 304.
I did not even start out with it trued up. Just chucked up a round and hit it with the grinder. In just a few passes it was running dead true where I ground it. Not bad. I know these motors are pretty decent. A mini lathe setup right can take a decent cut. This is the same motor powering a little grinding disk so it has some ooomph.

Steve

[S_J_H]

You'd have to bore out the bearing pocket to fit angular contacts -- the smallest AC with that bore size is the 7201: 12 x 32mm. A pair would be quite a bit deeper too, but you might be able to use one on each end and (cough) preload the beaings end-to-end with the spindle shaft, like the Dumore spindle does.

Yep already thought about that, Piece of cake job. As it is now it uses bearings at each end and preloads them as you mention.
I did find some 7001 ceramic angular contacts. Don't know if they would work well.

[oldtiffie]

As Steve says, its not as bad unit at all for the price. I am quite prepared to do as Steve has said and change the bearings and/or make a new shaft. All the basics are there even if it could have been designed a bit better - but not much.

The wheel is 80mm which is a bit small after wear and it wanting to get into a tight corner but a 5" saucer (preferred) or cup (2nd. choice) wheel will fix that.

I had to modify - make a new - set of flanges but that was no big effort. I may make a new set to cater for the 5" wheels with the standard 1 1/4" (31.75mm) grinder (surface, T&G) core.

Steve's idea for an ER-16 collet set in place of the drill chuck is a very good one as it will cater for all spindles/shanks in the ER-16 range. A drill chuck with a straight shank to suit the ER-16 range would be just what is required. I intended to use that feature for internal TP grinding.

I too was very impressed with the accuracy of the chuck - same as the ones that came with a 3MT taper for my HF-45 and "Sieg" X3 mills - very impressive.

As Steve says, there is plenty of "grunt" in the motor too.

The wiring is such that the grinder goes at 7,000RPM and the "drill" at half that. Things electrical are my weak point. I'd like to reverse or be able to reverse the spindle directions so that I could have it at 0>7,000 RPM at the "drill chuck" end for small internal grinding as well as drilling and milling.

I had seriously thought of mounting the TPG on either the "Y" or "Z" dove-tails of my vertical square-column dove-tail mill and mounting my small (6 x 12) micro-lathe on the mill table as a sort of universal grinder.

A lot of the requirement and work on the TPG went out the door when I bought my Universal T&C grinder which has an excellent work-head and grinding head on it - but while it is a very good external cylindrical grinder it still needs an internal grinder. The LMS TPG has been resurrected for that as it will do fine. For smaller work, I will also make and mount my "Proxxon" grinder - another LMS buy:
http://www.littlemachineshop.com/pro...3033&category=
for smaller internal grinding. That grinder is marvelous - good in every way - including power and speed control. My air driven die-grinder has not been used since I bought the Proxxon (I gave my electric die-grinder away!!).

LMS has a good range of spares for its grinders as well and that is one of the main reasons I bought them. I live in OZ and I've bought quite a bit of stuff from LMS and CDCO - excellent service - not a problem at all.

Good cylindrical grinders open up a whole new world for the HSM shop as hardened (including work-hardened) stuff becomes quite "do-able". They open up the scope of finer accuracy and better surface finishes than is generally the case with "pointed" tools. The TPG has been the "poor realtion" of surface and T&C grinders for no real reason.

I am really looking forward to Steve's work on and with the TPG - especially so if he puts it to work on his line-boring machine (a fabulous project).

[S_J_H]

Tiffie,
I to want the full speed for small drills/endmills.
I think a DPDT switch at the motor leads would allow one to reverse the direction of the motor and be able to run high speed in the proper drilling/milling rotation.
Steve

[macona]

Oh, please, please, please tell me you covered the machine before you started grinding.

A TP grinder is one of the fastest ways to ruin a lathe. You cant be too careful. Ideally use plastic under oiled cloth. Or at least a very fine thread count cloth. Grit is much smaller than you think.