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Buma cylinder borer

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  • Buma cylinder borer

    Yes that's the name of the machine
    here's a pic here

    What I would like to know is how does the motor mount on this machine ......found it in a scrap yard ...cost me آ£4...(NO MOTOR)
    would be nice to see pictures of the same machine being used ...that maybe someone else has i can figer out how to use it.
    all the best......mark

  • #2
    Interesting piece of equipment. How about a photo of the bottom end of it?
    To invent, you need a good imagination - and a pile of junk. Thomas A. Edison


    • #3
      There you go ...the business end

      all the best....mark


      • #4
        I will venture a guess and say that once it is bolted to the block through the rectangular hole in the base a hinged motor bracket is fastened to the slots in the side of the base with T nuts.

        I would love to have a toy like that one.
        To invent, you need a good imagination - and a pile of junk. Thomas A. Edison


        • #5
          I used one very similar,we call them "road side rebores"

          The motor hinges off the pin to the left of the pulley,its made to pull the motor on and off during setup on a job,since the unit is portable its also good to shed the motor while moving.

          Those are very handy units,you can setup and bore the cylinders in your car/boat/tractor or truck with it still in the frame,not to mention reboring pins and bushings on heavy equipment.I are jealous
          I just need one more tool,just one!


          • #6
            One sold on ebay a few weeks ago
            item number


            Have emailed the seller and the buyer for info or pictures
            still waiting
            all the best........mark


            • #7
              I have owned & used several types of portable cylinder boring bars over the years (Buma, Van Norman, Wandess, Shaftsbury, etc, etc), & bored many thousands of cylinders (and other less obvious jobs) with them. As with every other machine tool they vary in quality & the success, or otherwise of their design & construction.
              The Buma, as I recall(probably ten years since I owned / used one), was available in two sizes, the one shown looks like the smaller version with a boring size range of approximately 2" to 4". The motor swung from the pin at the rear & tensioned the belt by its own weight, there was an adjustable rubber damping pad in the casting beneath the motor. The method of clamping the bar to the block or cylinder stand was unusual & had a round bar that located in the slots in either side of the base casting. The box of setting tools that go with these boring bars is essential as it contains several sets of centering fingers, cutting tool setting micrometer, tool dressing fixture & I think there may have been different sizes of garter spring for the setting fingers. The cutting tips were carbide tipped round bar of quite large diameter (perhaps 3/8") which lent itself well to grinding up odd shaped tools for other opperations such as liner chamfering etc. The outer face of the belt pulley was a diamond faced lap & the tool dressing fixture slid onto the shaft in front of the pulley. The feed was provided by the vertical threaded shaft which rotated when disengaged, tightening the clamp screw stopped the shaft rotating & started the feed.
              In use the Buma could produce quite good results (more than adequate if hone finishing cylinders after boring) but was limited to fairly light cuts as the motor would bounce wildly & cause tool chatter under heavy loads. (a Van Norman 944 will handle twice the depth of cut without problems)
              Nonetheless these boring bars can produce some surprisingly accurate deep hole bores from what is a very compact & economical little machine.




              • #8
                I wondered what the shaft sticking out was for I know its for the dressing fixture ...thanks.
                I posted on uk rec classic cars about it....there only answer was to sell the thing.
                cant the "verdict" dial gauge be used in this.
                my aim is to get it fully functioning ....give it a try on an old engine .......see how it performs and whats involved.......if its too much hardwork or it does not do a good job ...then it's going on ebay
                Thanks for the detailed info Brian answer so far.
                all the the best....mark

                [This message has been edited by Mark Jones (edited 06-20-2004).]


                • #9
                  I ran something that looked a little like that but it was a VanNorman brand and the motor was an intrinsic part of the casting.

                  The first time I used it was about 30 years ago and the machine was in mint condition then. The machine never saw an engine block. The first job was very abusive and the jobs for it never got any better. For an example, the first job was to turn the OUTSIDE diameter of a dragline stump(center pin)that had been welded up.The stump was about 12" in diameter and about a foot tall (small dragline).It had turned about a half dozen that I know of but these weren't welded,turned first and then sleeved.
                  This machine has bored out numerus articulating joints on many different size front end loaders,even the hinge pin joints on a Tonka truck and various and sundry other jobs,but never an engine block.That machine has been throughly abused,but when I left there in 96 it was still useably. TOUGH!

                  Jim W.


                  • #10

                    Not entirely sure what your objectives are with this boring bar project but your comment "if its too much hardwork or it does not do a good job ...then it's going on ebay" perhaps suggests that ebay is indeed the place for it.
                    Alternatively should you have a need for this type of machine here are a few thoughts based on my experience of using/maintaing/re-building various boring bars over the past 25 years.

                    You paid less than the cost of two pints of Guinness for it, a quick web search found a Buma for sale at a machinery dealers for آ£1,250 which I suspect is probably a reasonable price for a tidy machine with all it's original kit.


                    The only English manufactured boring bar still in production is the Shaftsbury (of which I own two) that sell's new for آ£4,000. Some good pics & info at the following link which gives an idea how they are used etc.


                    I am assuming that you have only what you show in the pictures & will need to make everything else, most of which could probably be made on a small lathe with milling attachment, materials cost should be quite modest, time & effort could be considerable but I can quite understand that aspect being seen as a satisfying & rewarding challenge to many of us who contribute in this group.

                    About the only thing that renders these type of boring bar useless (and this applies equally to any used boring bar) is if the main column and / or the column housing is worn out through excessive usage, you will never compensate for this & all you will achieve is tapered and out of round bores. Your pictures show quite a lot of rust pitting on the column but this would not effect accuracy if cleaned up carefully.

                    To evaluate the viability of the boring bar I would suggest the following.

                    1/ Clean the whole thing carefully & wash off any abrasive residue with parrafin or similar, be careful if blowing off with compressed air not to force grit & dust into the column or drive area's, when dry give everything a coat of 3 in 1 oil & let some soak down into the column bearing housing. Clamp the boring bar safely to the edge of a sturdy bench so that the column can be lowered, then engage the feed & turn the belt pulley by hand to run the column downward, check that the vertical drive shaft & feed screw are not bent, if so they will need to be removed & straightened before proceeding. Assuming all is ok & the feed drive works run the column fully up & down several times, cleaning off any further rust or dirt & lubing as you go until you can get a consitent feel to it's movement. There should be some resistance in the column which is necessary to prevent the column dropping under it's own weight in use & to take up backlash in the feed gears. If the resistance felt in the column is fairly consistent throughout it's travel then the column & housing are probably ok, if the column has resistance but then becomes very loose when about 4" down the thing is probably worn out & beyond economical repair.

                    2/ Assuming a "so far so good" situation the next thing would be to completely strip, clean & inspect the machine, the drive gears & cutter head bearings were lubricated by high fiberous grease which hopefully should have prevented any rusting of the bearings etc. Perhaps though, at this stage it might be best to consider the accessories that you will need to make or aquire.

                    3/ Drive motor should be cheap enough second hand, drive pulley & motor mounting brackets relatively wasy to make up. The motor switch was mounted on the left side of the machine which is not shown in your pictures.

                    4/ Centering fingers will have to be made up in different lengths but you have one set to copy & the lengths required to cover the machines capacity can be worked out from the present set. I seem to remember there were maybe 4 0r 5 sets in the Buma setting kit. The garter springs for retaining the fingers are similar to what I have seen on domestic washing machines to retain hoses.

                    5/ Cutting tool holders were not too complicated & could be made quite easily. Suitable carbide tipped cutting tools should be available commercially. Cutter dressing fixture may not be essential but could be machined up from alluminium. The diamond dressing wheel should be on the end of the pulley, if this is missing could be expensive but again may not be essential if you are skilled at dressing cutting tools.

                    6/ Cutting tool setting micrometer is probably the trickiest & most expensive item, but with a little ingenuity I think something could be devised, possibly utilising a digital vernier caliper.

                    7/ Clamping fixtures for mounting the boring bar to a cylinder block can be made quite easily at very little cost.

                    Hope the above helps



                    • #11
                      i have an old 1/3 hp industrial sowing machine motor that should do it.
                      as for the fingers
                      what happens there ..
                      I take coil spring off and they stay put
                      they dont spring out ....should they.
                      had a look at the sites , one has a manual i had a sudy of that ...thanks.
                      ALL the best...mark


                      • #12
                        The knurled wheel at the very top front of the machine when turned clockwise expands the centering fingers, when turned anti clockwise the fingers retract courtesy of the garter spring, slip the garter spring off the fingers & they should slide out completely, I think they were probably numbered to correspond with numbers next to each hole.