Sanford Surface Grinder - Disassembly Part 1

[@hilltopmachineworks2131]

Just a suggestion here. Purchase a common thread pitch of threaded rod. Machine up the nut to fit. Add a DRO and that way you won't need the dial or care that it is incorrectly reading.

[@tomnorton8218]

Hey, I'm just a woodworker but that's what I was thinking!

[@melgross]

@@hilltopmachineworks2131 that’s a problem for surface grinders. You need a fairly tight fitting for the thread. Otherwise the play will result in a height setting that’s almost impossible to get accurate. You can try to make the nut adjustable, but that doesn’t work well with a standard 60 degree thread. You would have to buy a precision thread and nut, or make your own. McMastercarr sells decent ones. You can also buy an acme thread nut and rod. McMastercarr also sells those in high quality and even for mead screw accuracy, but they are expensive. But the problem is that trying to go a tenth or two with a standard tolerance screw and nut is going to be an issue and the wheel might bounce as you go across the work. This is a problem, but I’m sure he’ll figure something out.

[@MyLilMule]

That's one option I am considering. It's at the top of the list for the moment. I could also replace the lead screw with a common pitch, then change out the bevel gear and end up with the same .050" per rotation.

[@thomasstover6272]

@@MyLilMule That sounds the best to me, but mainly because you get to make new gears! A 4:1 gear pair would give you some good options, I think.

[@MyLilMule]

@@thomasstover6272 From what I have read and seen on YT, cutting a bevel gear requires a different cutter than a typical involute gear cutter? I'll have to do some research to see where I can get those (probably from China in order to make them affordable). If I use an 8 TPI screw and remake the 48 tooth bevel gear to 40 teeth, I would get a 2.5:1 ratio and my handwheel will still be graduated correctly. And keep the same pinion gear, that is. Would be a fun project on my K&T.

[@djscottish]

I have the smaller Sanford 48 Bench top grinder and have done some minor readjustments. Overall it's a very simple machine but with some strongly built features. I'm not sure of your plans for this machine in the future, but I would put in a vote for leaving the screw as is for now. A friend of mine has a saying: "An old machine might be 90% used up, but it will take another lifetime to use up that last 10%." I look forward to seeing what you decide for the restoration.

[@MyLilMule]

Excellent points. I haven't decided what I am going to do just yet. I need to see what the rest of this machine looks like before I invest any real money into it.

[@Just1GuyMetalworks]

She's certainly seen better days lol.

[@MyLilMule]

That's the truth.

[@chuckinwyoming8526]

A change gear lathe with 1.2 to 1 gearing to a 8 pitch lead screw will allow you to chase a new Z screw and nut with 6.666,,, pitch. But the idea of a standard 3/4 by 6 acme thread and DRO may be the best.

[@MyLilMule]

I would probably opt for 3/4-8 for more sensitivity.

[@RustyInventions-wz6ir]

That is a nice machine. Something I also would like to add to my collection. Nice video

[@MyLilMule]

Thanks for watching!

[@jagboy69]

@RustyInventions-wz6ir Little 6x12 grinders always pop up on fleabay. I got a Schultz for not a lot of money. I seldom use it, but it's small and doesn't take much space. That's the good thing about these small manual grinders. But they make a BIG ol mess! I parked mine near the door and shoot the sparks outside.

[@Randysshop]

Hi I have a Sanford MG surface grinder and just Finished doing a restoration on it, on mine the cross feed lead screw was worn out. SO made new screw and brass nut, and added a height gage with 1/10th indicator and that is what I look at. Good luck.

[@MyLilMule]

That's something I am thinking about. I am leaning toward putting a DRO on it and just using a common thread pitch acme lead screw. We'll see. I'd also like to find the front wheel guard, or at least one I could borrow and cast a replacement for mine. Some day.

[@mitchellgould5269]

my lathe can cut the 6 2/3 pitch. more accurately it's a 21 diametral pitch. (21 threads per 3.142")

[@MyLilMule]

I suppose I could probably do something with a stud gear to get mine to do it. Not sure it's worth the effort, TBH.

[@davidmasters9793]

It's called a torrington bearing

[@MyLilMule]

Torrington is a brand of bearing, now owned by Timken. It's like Kleenex. Not all facial tissues are made by Kleenex, but a lot of people still call anything like it a Kleenex. Not all needle roller bearings are Torringtons, although these might have been made by Torrington, they are too small for any manufacturers markings.

[@davidmasters9793]

@MyLilMule I'll make a mental note on that, all these years and still learning.

[@Engineerd3d]

I have an earlier version of that surface grinder. Mine came with no motor, I used a Hoover built motor on mine. Take note the motors on these surface grinders are balanced for optimal results. Also cast iron pulleys.

[@MyLilMule]

Good information to have. Thanks.

[@Rustinox]

With all the grinding dust on it, it looks like the machine has been eating itself for many years :) As for the lead screw... that's a problem. Maybe there is a way to make a new one with another pitch and adapting a new dial. Or Tom's idea is very good too.

[@MyLilMule]

New lead screw with a different pitch is also an option high on the list. I could also make a new bevel gear that will give me back the .050" per rotation.

[@Chromevulcan]

I don't suppose you could cut a 3.8mm thread with one of your machines? You could make a new acme lead screw and nut for the z-axis at 3.8mm and it's almost exactly 6-2/3 tpi.

[@MyLilMule]

I can't cut anything metric. I have a few ideas, one of which is to use an off the shelf lead screw and nut and use a DRO, ignoring the hand wheel. Another is to remake the pinion and bevel gear so the new lead screw gives me the right .050" per rotation of the handle. I need to check out the rest of the machine first before I put any money into it. It might be in such bad shape, it's not worth "fixing."

[@Chromevulcan]

@@MyLilMule Adding a DRO would eliminate the error completely. If you're willing to replace the bevel gear then you might be able find a combination that allows you to make your own lead screw and save the cash. I'm looking forward to the rest of this project and seeing what you decide.

[@johncrisman576]

Greg, this is the type of project that really gets my juices flowing. I recently restored a SB9A lathe and thoroughly enjoyed the process. Would love to find an other candidate like a Bridgeport or a small K&T horizon mill. A retired machinist friend of mine asked me if I really need one. My answer was “No. What’s your point?”.

[@MyLilMule]

LOL! What does that word "need" even mean? 😂 The thing I have learned is that when you see it, and the price is even close to what you want to pay or less, buy it. Even if it sits for years. You'll regret passing on it. Taking this surface grinder apart, I still regret passing on a Boyer-Schulz that was in much better shape. Oh well, lessoned learned.

[@TheAyrCaveShop]

I have the baby brother to that grinder ( bench top ) it’s a nice little grinder.

[@MyLilMule]

I think I recall seeing your video when you got it. Do you use it much? I can't say I will likely get much use out of this, but better to have it and need it than the alternative. LOL!

[@TheAyrCaveShop]

@ I don’t use it much but it sure handy when you need it. Really good at dressing up high-speed steel lathe bits

[@MyLilMule]

@@TheAyrCaveShop Or shaper bits. ;)

[@thomasstover6272]

I’m not surprised to see the loose fan. I thought your startup/shutdown noise sounded like a loose pulley, but a loose fan would sound like that, too. Hope the spindle is good!

[@MyLilMule]

I'm just glad it wasn;t a bearing.

[@junkmannoparts9696]

Hi use a pic or small screwdriver in one hand and pliers in the other at one edge of the snp ring . JM Geag hears a idea you could drill and tap the end of the motor and install a small drive dog or make a bushing . I think when it was new the fan was press fit .

[@MyLilMule]

Once I get the motor back on, I will see if it still sounds like a cat in heat. If it does, I'll look at remachining the bore in the fan. I don't think it was quite a press fit, maybe just a bit looser than that, thus the need for the wavy washer.

[@junkmannoparts9696]

I think your right it was probably a snug fit . anything you can do to keep it from spinning it won't give to anymore trouble . i have a baldor motor had same thing mine has a small lip with a hitch pin i crimped back down and i think i used a bit of JB weld to keep it from spinning . Good luck

[@TheKnacklersWorkshop]

Hello Greg, The design of your surface grinder is similar to mine. I look forward to tagging along with this project... You may want to think about buying or making some Fox Wedges, the are perfect for the job you used the wood chisel for. Sorry for being on the missing list. Take care. Paul,,

[@MyLilMule]

I wasn't aware of fox wedges. Those chisels are cheap junk, and never hold an edge. Ruining them is the last thing I care about. LOL

[@Bristolcentaurus]

another vote for using std acme thread, make a nut to suit use an indicator for your cut depth

[@MyLilMule]

It will likely work, at least somewhat, but I am honestly not sure it would be much better than a worn out thread. The original screw would have had square threads for increased accuracy. I would lose some of that with an acme thread, but I don't know, yet, just how much.

[@Bristolcentaurus]

@@MyLilMule accuracy is governed by thread fit not form (think micrometers) - square or acme give increase surface area for strength and wear - if acme is good enough for lathe lead screws ... pick one that give a thread advance that make re-calibrating you hand wheel dial easy

[@MyLilMule]

@Bristolcentaurus if that was true, then this would have not been a ground square thread. Lathes are not designed for .00005” tolerances. Surface grinders are. I just disagree.

[@Bristolcentaurus]

@@MyLilMule then you are going to have to find (a) a thread from and (b) a supplier that can machine to your stated tolerance of .00005” good luck with that

[@jagboy69]

Not sure if someone has warned you yet... But stay FAR AWAY from the spindle bearings. Seriously, DO NOT FK WITH THEM! They can be stupid expensive or not available at all. For now, I suggest you tell yourself they are fine until you can test run this thing grinding. Then if they are bad, you can go down that road or junk the entire thing. Savvy???

[@MyLilMule]

That's what I am thinking. We shall see.

[@ThePottingShedWorkshop]

Looking at all that accumulated dust in the motor, you have to wonder how much ended up in the operators lungs!

[@MyLilMule]

I know!

[@michaelclark9409]

I knew I was right! You always see those wood worker nuts using those sharp pry bars for chipping off chunks of wood.

[@MyLilMule]

lol

[@greg4367]

Why are you cleaning up that machine, it pretty much matches the rest of your shop as it is?

[@MyLilMule]

To make people wonder about my sanity.

[@greg4367]

As another KZbinr likes to say, "It's OK to be a little bit crazy".