We’re starting to use our 1983 Proth PSG 3060AH. So far all ok EXCEPT the Downfeed dial is only about 4” diameter and is marked only in thousandths. So you really can’t feed one or two tenths like you need to do unless you get a death grip on that knob, hold your breath, hope like Hell you don’t fart, and muscle it a teensy bit, then it might move 2 tenths or 8 tenths, can’t really control,it. Is there some “fine downfeed” knob we haven’t found yet? Anyone else run one like ours? We got a manual from Proth but it was for the PSGS, not PSG.
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Where’s precision downfeed on Proth PSG surf grinder?
- Thread starter Cannonmn
- Start date
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implmex
Diamond
- Joined
- Jun 23, 2002
- Location
- Vancouver BC Canada
Hi Cannonman:
Without being too much of a dick about it....here's what I have to say:
It's a PROTH!.
These were always low end grinders...OK for grinding plates to loose tolerances and average finishes, but they were never intended to be anything else and their construction reveals that.
So my apologies for the dickish comment above, but you sadly cannot have super high expectations for this grinder, and routinely grinding to tenths with the dials alone is one of those expectations.
Having said that, I have used a Kent (and a Proth) at various times and they are very similar machines.
I owned a Kent for decades and I ground a lot of sophisticated tight tolerance stuff on it, in spite of its shortcomings, so all is not lost.
On my Kent the downfeed was identical to your Proth, and the way I'd kiss tenths, was to tap the downfeed handle with my index finger while watching the vernier scale and also smearing the job with Sharpie then dusting it off with the wheel.
I could pretend to reliably grind 2 tenths that way.
The Jones and Shipman I have now does have a half tenths graduation on the downfeed and I can mimic what I did routinely on the Kent with the J&S and the result is the same as close as I can measure...it's just that I need not screw around so much.
So a bit of technique will be needed to get you there, but it can be done.
Be sure the grinder is in good nick...it has to grind nice and flat, and the spindle needs to be good.
You can benefit from balancing your wheels properly and you can benefit from selecting and dressing your wheels properly.
Grind wet when you can, don't push the machine too hard (Proths have wimpy spindle housings and short downfeed ways as I recall so the head on the machine I ran in the early 1990's was floppy even when new.
We parked a lump of steel on the head to give it a bit more mass, except when slot grinding with it and we needed the spindle to be reasonably square to the table.
But it was mostly a plate grinder so the spindle weight rarely moved.
So despite my sniffy remarks, you can turn it into a perfectly usable grinder...just don't expect it to be as good as a hundred thousand dollar Okamoto.
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
Without being too much of a dick about it....here's what I have to say:
It's a PROTH!.
These were always low end grinders...OK for grinding plates to loose tolerances and average finishes, but they were never intended to be anything else and their construction reveals that.
So my apologies for the dickish comment above, but you sadly cannot have super high expectations for this grinder, and routinely grinding to tenths with the dials alone is one of those expectations.
Having said that, I have used a Kent (and a Proth) at various times and they are very similar machines.
I owned a Kent for decades and I ground a lot of sophisticated tight tolerance stuff on it, in spite of its shortcomings, so all is not lost.
On my Kent the downfeed was identical to your Proth, and the way I'd kiss tenths, was to tap the downfeed handle with my index finger while watching the vernier scale and also smearing the job with Sharpie then dusting it off with the wheel.
I could pretend to reliably grind 2 tenths that way.
The Jones and Shipman I have now does have a half tenths graduation on the downfeed and I can mimic what I did routinely on the Kent with the J&S and the result is the same as close as I can measure...it's just that I need not screw around so much.
So a bit of technique will be needed to get you there, but it can be done.
Be sure the grinder is in good nick...it has to grind nice and flat, and the spindle needs to be good.
You can benefit from balancing your wheels properly and you can benefit from selecting and dressing your wheels properly.
Grind wet when you can, don't push the machine too hard (Proths have wimpy spindle housings and short downfeed ways as I recall so the head on the machine I ran in the early 1990's was floppy even when new.
We parked a lump of steel on the head to give it a bit more mass, except when slot grinding with it and we needed the spindle to be reasonably square to the table.
But it was mostly a plate grinder so the spindle weight rarely moved.
So despite my sniffy remarks, you can turn it into a perfectly usable grinder...just don't expect it to be as good as a hundred thousand dollar Okamoto.
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
Last edited:
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
In addition to Marcus's comments, I used to routinely bump the spindle down a tenth or two on grinders without good fine adjust from big Mattisons to little 6x18s by using a light tap on the top of the grinding head with a dead blow (soft plastic) hammer. My procedure was to put a tiny bit of tension on the handwheel first and then give a couple light taps until I got the movement I wanted. Doesn't take much of a tap at all, could probably do it with the heel of your hand just the same. This is especially helpful on machines where the head is a little prone to dropping too far when trying to adjust with the handwheel.
If you don't have a good tenths DRO, put a tenths indicator on the head of the grinder. Hearing of a grinder with only .001" resolution on the downfeed is a first for me. I've never used one that didn't have tenths on downfeed myself.
If you don't have a good tenths DRO, put a tenths indicator on the head of the grinder. Hearing of a grinder with only .001" resolution on the downfeed is a first for me. I've never used one that didn't have tenths on downfeed myself.
Thx for advice. Primary operator ground some 4140ph after making changes he got from his own thread, using same machine, came out much better.
. I played with downfeed handwheel a bit and watched the reference arc having 10 or 20 thou either side of zero. The handwheel has about a little lost motion and I found that by moving the wheel to the end of lost motion, away from the down direction and giving it a nudge so it’d freewheel and tap the shaft at the end of lost motion, it would let me lower the wheel one or two tenths at a time. Here’s his video of his latest trial, maybe u saw on his thread.
CarbideBob
Diamond
- Joined
- Jan 14, 2007
- Location
- Flushing/Flint, Michigan
Noga mag base on column. 50 millionths DTI on spindle housing or nose.
Problem solved.
Problem solved.
Thx, he tried exactly what u describe, good to know someone else does it that way. We started looking for tenths one-axis DRO’s but no use for their range, few have tenths res, and are expensive.
implmex
Diamond
- Joined
- Jun 23, 2002
- Location
- Vancouver BC Canada
Hi Cannonman:
On a Proth of that size you should have enough poop to keep the wheel turning and not slow it down when you run a normal DOC and WOC.
What kind of DOC and what kind of crossfeed increment is your guy running?
The one I drove was not short of horsepower but it really wasn't a hogging machine...it was way too lightly built for that.
Are you sure you are getting enough juice to the motor?
Are you sure the motor is still good?
What is the nameplate HP of the motor and what size and grade of wheel are you running?
A wheel that wears quickly to a long taper across its face will bog the machine down, but it'll do that with any of these smaller grinders.
Is your guy an experienced grinder hand or is he feeling his way forward?
BTW, the hardness of the steel will not have a noticeable effect unless it's something like abrasion resistant like D-2 which tears the shit out of the wheel, making that long taper across the wheel face that I was on about.
4140 HT is easy to grind and should give no problems.
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
On a Proth of that size you should have enough poop to keep the wheel turning and not slow it down when you run a normal DOC and WOC.
What kind of DOC and what kind of crossfeed increment is your guy running?
The one I drove was not short of horsepower but it really wasn't a hogging machine...it was way too lightly built for that.
Are you sure you are getting enough juice to the motor?
Are you sure the motor is still good?
What is the nameplate HP of the motor and what size and grade of wheel are you running?
A wheel that wears quickly to a long taper across its face will bog the machine down, but it'll do that with any of these smaller grinders.
Is your guy an experienced grinder hand or is he feeling his way forward?
BTW, the hardness of the steel will not have a noticeable effect unless it's something like abrasion resistant like D-2 which tears the shit out of the wheel, making that long taper across the wheel face that I was on about.
4140 HT is easy to grind and should give no problems.
Cheers
Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
It should not be slowing the wheel down, which is why I mentioned it...
If you were hogging with a wide cross step, maybe. Plunge grinding, probably. Not with a grind like that.
If you were hogging with a wide cross step, maybe. Plunge grinding, probably. Not with a grind like that.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Some/many Tc grinders are that way, with having a small number dial on the down feed and on the cross feed. If they have half thousandth lines that is an asset but some don't even have that so it is a turkey shoot. We would bump the hand wheel with looking at the sparks and tickle off tenths of Barber Collman reamers to split tenths with a Cincinnati #2 TC grinder..the older ones had a very small number dial only in thousandths. I guess it is just getting used to bumping the wheel and counting the sparks.
some grinders like Landis, Brown & sharpe, Norton and others had a pick feed for tenths..that's handy. But with an old thousandth micrometer, we would read 2 1/2 tenths just estimating between the lines spacing and make +- one tenth.
I guess one could throw the big hand wheel on the grinder, mill or a lathe and cut lines in the hand wheel OD, or add a tenths DRO..
some grinders like Landis, Brown & sharpe, Norton and others had a pick feed for tenths..that's handy. But with an old thousandth micrometer, we would read 2 1/2 tenths just estimating between the lines spacing and make +- one tenth.
I guess one could throw the big hand wheel on the grinder, mill or a lathe and cut lines in the hand wheel OD, or add a tenths DRO..
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michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
A 60 grit, too hard wheel might do just that, Load up..and then finallly self-dress and cause the wheel to slow-down and speed-up.
along with trying straight across the part long travel.
I would not b cross-feeding 1/8"
ok guess we’ll put a 46 wheel on, dress it, and crossfeed about 5 thou, see if those allow wheel to maintain rpm. Our crossfeed is divided into 1/2 thou. Wheels we normally use are 7” dia x 1/2”. Somewhere we got a case of new, purty white wheels, 7 “ x 1” 46 grit, with rebated center, any cautions on using those?
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
Cross increments .oo5 is a very small but good amount to prove the grinder's merit... a normal grind might be crossing more like .020 to .060.. and a normal long-travel feed rate, not full out fast.
looking about like this: wait I will find it, give me a few minutes.
QT: (Purty white wheels, 7 “ x 1” 46 grit,) A great wheel... *what is the hardness?
You may need to prop out your wheel guard..that OK.
Long travel about like this...
www.bing.com
or this:
www.bing.com
Pretty much between 300 and 500 IPM with a 1/2"+ over travel at long ends/ fresh dress , stick the wheel with slight rub with a piece of wood like a popsicle stick, part straight long ways on the chuck, bump the lead and follow edge 1/64th bevel, wet, *don't use crisis cross feature if you have that....
then post a still photo
OH, (scrape some mucky muck out of your coolant tank.)
OH , run the machine for 5 minutes or more before running the part.
I have never run a Ptoth but it looks like a decent machine.
Buck
Ps, you can use those 1" wide wheels ..just take .020 x 1/2 ' off the bottom when/if they are too wide, * but for the part in process use the the full !" widthr.
looking about like this: wait I will find it, give me a few minutes.
QT: (Purty white wheels, 7 “ x 1” 46 grit,) A great wheel... *what is the hardness?
You may need to prop out your wheel guard..that OK.
Long travel about like this...
proth surface grinding machine - Bing video
proth surface grinding machine - Bing video
then post a still photo
OH, (scrape some mucky muck out of your coolant tank.)
OH , run the machine for 5 minutes or more before running the part.
I have never run a Ptoth but it looks like a decent machine.
Buck
Ps, you can use those 1" wide wheels ..just take .020 x 1/2 ' off the bottom when/if they are too wide, * but for the part in process use the the full !" widthr.
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Cross .oo5 is a very small but good amount to prove the grinder's merit... a normal grind might be crossing more like .020 to .060.. and a normal long travel feed rate, not full out.
looking about like this: wait I will find it, give me a few minutes.
7 “ x 1” 46 grit, great wheel what is the hardness?
or this:proth surface grinding machine - Bing video
pretty much between 300 and 500 IPMproth surface grinding machine - Bing video
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
The long ends over-travel 1/2"+ is for cooling the part time and letting the machine settle if there is any vibration/rock such as poor floor contact or some rattle from being on a pallet. for the part in process use the full 1" width.
OH, be sure the flange nut is two hands tight.. about as tight as what a normal guy can make with a hand on the wheel and a hand on a 6 or 7" long wheel wrench.
I make my wheel just a tad tighter than this, but two hands is OK.
(Some day I will measure the torque of what I make them.)
OH, be sure the flange nut is two hands tight.. about as tight as what a normal guy can make with a hand on the wheel and a hand on a 6 or 7" long wheel wrench.
I make my wheel just a tad tighter than this, but two hands is OK.
(Some day I will measure the torque of what I make them.)
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eKretz
Diamond; Mod Squad
- Joined
- Mar 27, 2005
- Location
- Northwest Indiana, USA
That is a good point about the (potentially too-hard) wheel loading up Buck, but do you think it'd do that right after a fresh dress? I would expect it'd take a while.
michiganbuck
Diamond
- Joined
- Jun 28, 2012
- Location
- Mt Clemens, Michigan 48035
If the wheel was an H hardness likely it might not load up, but being a 60 gt, not very open, and a harder letter hardness (if so all three) then early loading could occur.
QP"s part is likely a 10 to 12-minute job plus wheel change and dress.
And hardness is tricky because one wheel brand's L wheel may be harder or softer than another brand's L wheel..good to take a pen and mark a wheel's hardness where you can see it when mounted(if there is some blotter you can see). Good also to "mount -up" mark a wheel.
Always turn off the coolant, spin 30 seconds, and then park the wheel
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