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How far do you go when rebuilding/restoring a boring machine

Started by Brian Moore, October 15, 2011, 07:08:19 PM

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Brian Moore

Instead of Hijacking another thread I thought I would start a new post.    What is the standard practice for removing excessive play from the "drive" shaft of a Boring machine?    Do you just try to find a bushing that will take up the free play and go with that?   Do you ream out the body to accept a larger more substantial bushing?   Or do you weld up the "drive" shaft and have it turned back down to remove as much free play as possible?   I understand that we are talking about a Boring Machine for wood post and not gas engines.    However at some point, there has to be too much free play and when there is what do you do?    Or do you just scrap out the body when the free play is too much?     I am really curious about this.

Thanks to all that reply,

Brian Moore

Jim_Rogers

First of all what type or brand of boring machine are you talking about?

Also, you said "drive shaft" and I'm assuming you mean the vertical shaft. There usually are two shafts one vertical and one horizontal. If you mean the horizontal one then please let me know.

Some machines have play in the vertical shaft. This usually isn't a problem when you bore a hole. Because the bit tip centers the bit and the carriage may wobble a bit on the slides on the tower.

The purpose of using a boring machine is to "hog out" wood from a mortise. It is not a precision tool.

Even boring peg holes there usually isn't much problem if the carriage wobbles a bit on the slides.

Maybe tomorrow morning I can get my old machine out and show you in a video.

But anyway, some machines can have the bearing plates/covers taken off, such as with a Millers Falls machine.

Here is an example:


As you can see the four bearing caps/covers/plates have been removed. They are on the bench on the upper right, I have circled them with red circles.

These caps can be modified and by doing so make the shafts a little tighter. But you have to be very careful not to take too much off.

To make the bearing caps tighter, you grind/sand or remove by machining some of the metal on the flats where the mount to the carriage body. You only need to remove a little bit.

We have had machines here where someone removed too much and this caused the shafts to bind up. And shims were needed under the caps to hold them out in the right place.

If you machine has caps like this that can be removed you should number them and mark them so that you put them back in the same spot with the top to the top where it was after you have modified them.

If you machine doesn't have removable caps then I'm not sure what you can do. I'll have to discuss it with Tom as he does the tool restoration.

I hope this has helped you to understand how you can improve your machine, if you wish to.

Jim


Whatever you do, have fun doing it!
Woodmizer 1994 LT30HDG24 with 6' Bed Extension

shelbycharger400

well... in both instances...to do it right....it has to be torn down, all parts mic'd out.
Now as to your wood boring machine,  as with any wear on the shaft, shaft usually will be turned down, and a new bushing fabricated to fit.  if you have enough stock material, go with a roller bearing vrs bushing. 
Slightly oversize diameter on the bushing pressing in to the bore, and sometimes slightly undersize inside bore, then reamed to size , or a ball of correct diameter is pressed through.  ball burnishing is the best as it "packs and plates", or moves material around from high to low spots.  mostly done with aluminum, bronze or brass bushings.

machining isn't cheap, so if you can do the tear down, and checking parts diameters...do it.   micrometers and dial calipers are cheap at $50 to $100.        my dial caliper does both imperial and metric, cost me around 50 from a matco dealer 12 years ago, and it has a central tool sticker on it. 

Brian Moore

Thanks for the replies.   I have 3 different Boring machines.   1 is a Millers Falls knock off or unbranded.   Jim I understand what you are saying here (thanks for the Pics).    I should have been a little clearer about which shaft.   You are correct the "vertical" Shaft is the one I am talking about.    The other two that I have are (I believe James Swan Models)  one is fixed and the other adjustable.    These are the ones that I have based my questions on.   They both are in working condition but I was wondering what everyone does when they come across these in poor condition.

shelbycharger400

brian. now i know what you have goin on.... do what jim said light sand the flats on the caps.     if its really bad, you can have it rebored.  i have come across similar removable caps on 1930's to 1950's presses ect used 1/2 shell oil lite bearings, if you can use them...i would, they have what looks to be small perforations in them, and just put wheel bearing grease in them

Brad_bb

Brian, this is a common condition in these boring machines that are 100+ years old.  What I've found with the millers falls vertical shafts, is that they are rather soft and tend to wear more than the bearing caps.  This also is a problem on several other features of the shaft, namely the threads for the set screw(many have been stripped and new ones tapped), and the drive pin that locks the gear to the shaft(a short pin that engages both parts).  One solution is a stronger shaft.  I am actually working towards making stronger shafts, for sometime early next year. With these new shafts, I plan to bore the bearing locations of the frame and caps and use oil impregnated bronze bushings.  The shafts will be the original size.  The bushings will not be easily noticed, and they will be replaceable.  They will be the wear component.  Improved shafts will also fix the other two problems I mentioned. 

It is important for any gear set to have proper engagement and alignment.  It is important for reducing wear and preventing excess stress on gearteeth.  Too far apart, and teeth make contact towards the tips, and that puts alot more stress on the root of the tooth.  Have you seen boring machines with broken gear teeth?  It's caused by this or by a defect in the casting.

These boring machines will tolerate some play because they are cast gears.  But that doesn't mean you don't need to align them well.  I believe alot of problems in these machines stems from shafts wearing, thus allowing misalignment of the gears, leading to improper wear of the teeth, or fracture of teeth.  This is why proper alignment is so important.  It also affects how well they turn.  I hope to offer a solution in the future for Millers Falls problems.  I have some first sample parts being made now.  If all goes well, I would also like to do the same for the Boss machines.  My goal is to get damaged or worn machines back into service without compromising the original look.  I have 4 or 5 millers falls machines in various conditions and 4 Boss machines in various conditions.  I plan to repair most of these, hopefully with the new parts, and then sell them.  Hopefully this will preserve these machines for another 100+ years or more.
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

Just Me

 There is a barn boring machine listed on the Northern Michigan Craigslist right now for $50. Looks like it is all there. Not sure what they are worth but if you are interested.....

Larry

frwinks

Brad, please keep us posted on the MF bearing/bushing mod you're working on.  Mine is in mint condition, but I know of a couple of machines I can buy cheap that will need some attention. 
I stared with a wooden Snell looking machine I picked up for under $50.  As sloppy as it was, I still managed to cut half of my frame using it.  As Jim said, it's a rough tool, it's job is to quickly remove as much wood as possible. 

shelbycharger400

if you had access to a bridgeport, with some work, its possible to create new gears, then send out for flame hardening.
just have to do the math and have a turn table  :P

Brad_bb

Actually, gears are involute shape, not straight cuts for a mill.  A skilled machinist might be able to do it, but it really wouldn't be anywhere near cost feasible.  They can be shaped or hobbed as gears are typically made, but I've gone through that exercise, and once again, not cost feasible in small quantities.

@frwinks, oh I surely will let the forum know when I get far enough along. 
Anything someone can design, I can sure figure out how to fix!
If I say it\\\\\\\'s going to take so long, multiply that by at least 3!

shelbycharger400

straight cut gears can be made easy.  the involute is definately a challenge, but i know it can be done with the right tooling on a bridgeport... its way old school, prior to the cnc machines...its along the lines of a dividing head or cherring head related tooling. i stated it if for perhaps someone has something oddball that has the tooling abilities.  3 years ago i had a chance to buy a first generation bridgeport cnc with tape drive, i passed.,  movin forward in technology...  hobbin is the easiest way

shelbycharger400


Brian Moore


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