A repair device and usage method for flange threaded holes under space-constrained working conditions

Abstract

The present invention belongs to the technical field of repair of threaded holes, and specifically provides a repair device and a usage method for flange threaded holes under working conditions with limited space, mainly including a mounting plate and a positioning assembly; a first through hole, a plurality of second through holes and a repair machining position reserved corresponding to the threaded hole to be repaired are arranged on the mounting plate; the positioning assembly includes a positioning column member and at least one double-headed bolt member, the positioning column member includes a positioning end and a fixed end, and the diameter width of the positioning end is adapted to the diameter width of the eye hole; the positioning end is inserted into the eye hole, and the fixed end passes through the first through hole and is fixedly connected with a fastener; one end of the double-headed bolt member is in threaded connection with the threaded hole, and the other end of the double-headed bolt member passes through the second through hole and is fixedly connected with a fastener. The present invention can effectively ensure the condition of the remaining threaded holes when repairing the problem threaded holes, and improve the reliability of the threaded hole repair operation.

Description

Technical Field

[0001] The present invention belongs to the technical field of threaded hole repair, and in particular relates to a flange threaded hole repair device and a use method under space-constrained working conditions. Background Art

[0002] The steam generator is one of the main equipment of the nuclear island of a nuclear power plant. It has a reserved eyelet, and a connecting flange is provided at the eyelet. Four connecting threaded holes are provided on the connecting flange around the eyelet. In actual use, when the steam generator is transported to the power plant site and installed in place, it is sometimes found that some threaded holes have rotten teeth and cannot be used normally. The traditional treatment method is usually to expand and tap the problematic threaded holes and then install threaded sleeves to restore the design function of the threaded holes. In the prior art, a repair device and method are also proposed for this, as shown in the patent application with application number 202010429512.5.

[0003] However, in this method, the support plate needs to be fixed through the remaining three intact threaded holes, and a magnetic drill is set on the support plate to perform operations such as drilling, reaming and tapping. As a result, the vibration, equipment deadweight and construction risks generated during the maintenance operation will be transferred to the other intact threaded holes. Once the operation is improper, it is easy to lose sight of one thing while focusing on another. Moreover, when there are more than one problematic threaded holes, this phenomenon will be more obvious. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a flange threaded hole repair device and a method of use under space-constrained working conditions, which can effectively ensure the conditions of the remaining threaded holes when repairing the problematic threaded holes, thereby improving the reliability of the threaded hole repair operation.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A repair device for flange threaded holes under space-constrained working conditions, comprising a mounting plate and a positioning assembly for mounting and fixing a magnetic drill;

[0007] The mounting plate is provided with a first through hole corresponding to the eyelet of the connecting flange, a plurality of second through holes corresponding to the threaded hole of the connecting flange, and a rework processing position reserved for the threaded hole to be reworked;

[0008] The positioning component includes a positioning column member and at least one double-headed bolt member. The positioning column member includes a positioning end and a fixed end. The diameter width of the positioning end is adapted to the diameter width of the eyelet. In the installed state, the positioning end is inserted into the eyelet, and the fixed end passes through the first through hole and is fixedly connected to a fastener. One end of the double-headed bolt member is threadedly connected to the threaded hole, and the other end of the double-headed bolt member passes through the second through hole and is fixedly connected to a fastener.

[0009] Preferably, the positioning column member includes a bolt member, a follower member sleeved on the bolt member, a first wedge block sleeved on the bolt member, and a plurality of second wedge blocks arranged in cooperation with the first wedge block;

[0010] A sliding inclined surface is provided between the first wedge block and the second wedge block. The follower member can slide to contact the second wedge block as the bolt member rotates, and promote the relative sliding of the second wedge block and the first wedge block. The outer side surface of the second wedge block can slide to abut against the inner wall of the eyelet.

[0011] Preferably, the first wedge block is arranged in a frustum shape, and a plurality of first inclined surfaces are arranged around the central axis on its outer peripheral surface. Second inclined surfaces are correspondingly arranged on the inner side of the second wedge block corresponding to the first inclined surfaces, and the outer side of the second wedge block is arranged as an arc surface adapted to the inner wall of the eyelet.

[0012] Preferably, a countersunk head structure is provided on the side of the first through hole and the second through hole away from the connecting flange. The connection and fixation of the fixed end to the fastener and the connection and fixation of the double-headed bolt member to the fastener are both located in the countersunk head structure.

[0013] Preferably, an auxiliary positioning plate is further provided between the connecting flange and the mounting plate. The auxiliary positioning plate is provided with a hollow area corresponding to the eyelet. A positioning hole is coaxially arranged on the auxiliary positioning plate corresponding to the threaded hole, and a guiding hole is coaxially arranged corresponding to the threaded hole to be repaired.

[0014] Preferably, a protrusion is provided at the eyelet, and a concave surface is correspondingly provided on the side of the auxiliary positioning plate facing the eyelet corresponding to the protrusion.

[0015] Preferably, a guiding block is further provided corresponding to the guiding hole. The guiding block is detachably installed on the auxiliary positioning plate.

[0016] Preferably, a clamping groove is provided at the repair processing position corresponding to the guiding block, and the guiding block is clamped in the clamping groove.

[0017] A method for using a repair device for flange threaded holes under space - limited working conditions, which is applicable to the repair device for flange threaded holes under the above - mentioned space - limited working conditions, includes the following steps:

[0018] Pre - install the positioning column member on the mounting plate, insert the positioning end of the positioning column member into the eye hole provided, and set the double - headed bolt member in at least one intact threaded hole of the connecting flange to pre - fix and install the mounting plate;

[0019] Set a magnetic drill on the mounting plate, adjust the coaxiality of the main shaft of the magnetic drill with the threaded hole to be repaired, and then perform the operations of reaming and tapping step by step;

[0020] After tapping is completed, install a threaded bushing in the repaired threaded hole, and after removing the magnetic drill and the mounting plate, the repair operation is completed.

[0021] Further, when installing the mounting plate, an auxiliary positioning plate is provided between the connecting flange and the mounting plate. Positioning holes are coaxially provided on the auxiliary positioning plate corresponding to the threaded holes, and the double - headed bolt member is inserted through the positioning holes;

[0022] Guide holes are coaxially provided on the auxiliary positioning plate corresponding to the threaded holes to be repaired. Before reaming, first install a positioning rod on the magnetic drill, and adjust the coaxiality of the main shaft of the magnetic drill with the threaded hole to be repaired through the assembly relationship between the positioning rod and the guide holes;

[0023] Guide blocks are also provided corresponding to the guide holes. After determining the coaxiality of the main shaft of the magnetic drill with the threaded hole to be repaired, replace the positioning rod with a reaming drill, and sequentially perform reaming operations on the guide blocks and the threaded holes to be repaired.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] In this solution, the positioning column member is cleverly provided, and the diameter width of the positioning column member is set to be adapted to the diameter width value of the eye hole. When processing the threaded hole to be repaired, the positioning end of the positioning column member is inserted into the eye hole to form a top - contact with the inner wall of the eye hole, so that it can be used as the main force - bearing component to unload the force on equipment such as the mounting plate and the magnetic drill. Since the diameter width of the eye hole is larger than that of the threaded hole, the main force can fall on the positioning column member, thus playing a better protective role for the threaded holes that do not need to be repaired and ensuring the excellent state of the threaded holes that do not need to be repaired.

[0026] Moreover, during processing, only one of the threaded holes needs to be installed with the double-headed bolt component. However, with the installation of the positioning post component, the positioning and installation of the mounting plate can be achieved. While ensuring the state of the intact threaded holes, the double-point positioning method is simpler and more convenient to use, can effectively reduce the operation time, and has high flexibility, and can effectively handle the situation when 2 or 3 threaded holes need to be repaired simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of the present invention in the working state.

[0029] Figure 2 It is a schematic structural diagram of the mounting plate of the present invention viewed downward.

[0030] Figure 3 It is a schematic structural diagram of the mounting plate of the present invention.

[0031] Figure 4 It is a schematic structural diagram of the follower of the present invention.

[0032] Figure 5 It is a schematic structural diagram of the first wedge block of the present invention.

[0033] Figure 6 It is a schematic structural diagram of the second wedge block of the present invention.

[0034] Figure 7 It is a schematic structural diagram of the auxiliary positioning plate of the present invention.

[0035] Figure 8 It is a schematic structural diagram of the double-headed bolt component of the present invention.

[0036] Figure 9 It is a schematic structural diagram of the guide block of the present invention.

[0037] Wherein:

[0038] 1 - eye hole, 2 - connecting flange, 3 - mounting plate, 31 - countersunk head structure, 32 - card slot, 4 - magnetic drill, 41 - main shaft, 5 - positioning post component, 51 - bolt component, 52 - follower, 53 - first wedge block, 531 - first inclined surface, 54 - second wedge block, 541 - second inclined surface, 542 - arc surface, 6 - double-headed bolt component, 61 - convex ring part, 7 - auxiliary positioning plate, 71 - hollow area, 72 - positioning hole, 73 - guide hole, 74 - gasket ring, 8 - guide block. Detailed implementation manners

[0039] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the implementation manners of the present application and the features in the implementation manners may be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention. The described implementation manners are only a part of the implementation manners of the present invention, rather than all of the implementation manners. All other implementation manners obtained by those of ordinary skill in the art based on the implementation manners in the present invention without making creative efforts fall within the scope of protection of the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific implementation manners, and are not intended to limit the present invention.

[0041] Embodiment 1

[0042] As Figures 1-9 shown, in this embodiment, a repair device for flange threaded holes under space-limited working conditions is provided, which is mainly applied to the repair of threaded holes on the connecting flange 2 at the eye hole 1 of the steam generator in a nuclear power plant. Specifically, it includes a mounting plate 3, a positioning assembly and a magnetic drill 4. In this embodiment, the magnetic drill 4 is a German Black & Decker MAB800 magnetic drill.

[0043] The mounting plate 3 is a rectangular plate member. The mounting plate 3 is provided with a first through hole corresponding to the eye hole 1 on the connecting flange 2, a plurality of second through holes corresponding to the threaded holes on the connecting flange 2, and a repair processing position reserved for the threaded holes to be repaired. In this embodiment, three second through holes are provided. And based on the structural design of the connecting flange 2, two of the second through holes are symmetrically arranged on both sides of the eye hole 1 and are on the same straight line as the eye hole 1, while the connecting line of the other second through hole and the eye hole 1 is just perpendicular to this straight line, so that this second through hole is arranged on one side of this straight line, and the repair processing position is arranged on the other side of this straight line.

[0044] The positioning component includes a positioning column member 5 and at least one double-headed bolt member 6. The positioning column member 5 includes a positioning end and a fixed end. The diameter width of the positioning end is adapted to the diameter width of the eyelet 1. In the installed state, the positioning end is inserted into the eyelet so that a top contact is formed between the outer periphery of the positioning end and the inner wall of the eyelet 1, and the fixed end passes through the first through hole and is fixedly connected to a fastener. One end of the double-headed bolt member 6 is threadedly connected to the threaded hole, and the other end of the double-headed bolt member 6 passes through the second through hole and is fixedly connected to a fastener.

[0045] As a preferred solution, the positioning column member 5 in this embodiment includes a bolt member 51, a follower member 52 sleeved on the bolt member 51, a first wedge block 53 sleeved on the bolt member 51, and a plurality of second wedge blocks 54 arranged in cooperation with the first wedge block 53. A sliding inclined surface is provided between the first wedge block 53 and the second wedge block 54. The follower member 52 can slide to contact the second wedge block 54 as the bolt member 51 is tightened and rotated, and promote the relative sliding between the second wedge block 54 and the first wedge block 53. The outer side surface of the second wedge block 54 can slide to abut against the inner wall of the eyelet 1. Through the linkage between the components, the relative sliding between the first wedge block 53 and the second wedge block 54 can change the maximum diameter width of the outer periphery of the positioning column member 5, so that in actual application, the positioning column member 5 can adapt to eyelets 1 of different sizes and different inner wall conditions, further improving the applicability and reliability of the repair device.

[0046] Further, the first wedge block 53 is arranged in a frustum shape, and a plurality of first inclined surfaces 531 are arranged around the central axis on its outer peripheral surface. In this embodiment, a plurality of first inclined surfaces 531 are provided and are evenly arranged around the central axis of the first wedge block 53. The inner side of the second wedge block 54 is correspondingly provided with second inclined surfaces 541 corresponding to the first inclined surfaces 531. In the installed state, the first inclined surfaces 531 and the second inclined surfaces 541 are in flat contact. The outer side of the second wedge block 54 is preferably provided with an arc surface 542 adapted to the inner wall of the eyelet 1 to further increase the fit between the outer side surface of the second wedge block 54 and the inner wall surface of the eyelet 1, increase the stress surface of the positioning column member 5, and ensure stable stress.

[0047] In addition, a counterbore structure 31 is provided on the side of the first via hole and the second via hole away from the connecting flange 2. The connection and fixation of the fixed end to the fastener and the connection and fixation of the double-headed bolt 6 to the fastener are both located within the counterbore structure 31, so that the side surface of the mounting plate 3 facing away from the connecting flange 2 can maintain a high flatness, facilitating the installation and adjustment of the magnetic drill 4. Among them, the above-mentioned fastener is a gasket and a nut.

[0048] Furthermore, an auxiliary positioning plate 7 is also provided between the connecting flange 2 and the mounting plate 3. The auxiliary positioning plate 7 is provided with a hollow area 71 corresponding to the eyelet 1 to facilitate the installation and use of the positioning post 5; positioning holes 72 are coaxially provided on the auxiliary positioning plate 7 corresponding to the threaded holes, and guiding holes 73 are coaxially provided corresponding to the threaded holes to be repaired. In actual situations, the surface between the eyelet 1 and the outer side surface of the connecting flange 2 is not a flat surface, but there is a protrusion at the eyelet 1, which will affect the stable installation of the mounting plate in this case; therefore, a concave surface is provided on the side of the auxiliary positioning plate 7 facing the eyelet 1 corresponding to the protrusion, so that the auxiliary positioning plate 7 can be flatly installed with the eyelet 1, and then the outer side surface of the auxiliary positioning plate 7 is set as a flat surface to facilitate the installation of the mounting plate 3.

[0049] As a preferred solution, a guiding block 8 is also provided corresponding to the guiding hole 73. The guiding block 8 is detachably installed on the auxiliary positioning plate 7, such as being fixedly installed by screws. In addition, a card slot 32 is provided corresponding to the guiding block 7 at the repair processing position. The guiding block 8 is clamped in the card slot 32. Through the fixed installation between the guiding block 8 and the auxiliary positioning plate 7, the clamping connection between the guiding block 8 and the card slot 32, and the fixed installation between the mounting plate 3 and the auxiliary positioning plate 7, a linkage positioning is formed, and the overall structural stability is higher.

[0050] To facilitate the further understanding of this solution, in this embodiment, a method for using a repair device for flange threaded holes under space-limited conditions is also provided, which is applicable to a repair device for flange threaded holes under space-limited conditions as described above, and specifically includes the following steps:

[0051] S10. Clean the eyelet 1 and the connecting flange 2 at the eyelet 1, and select or set the double-headed bolt 6. Among them, a convex ring part 61 with a smooth outer surface is provided in the middle of the double-headed bolt 6, and at least one double-headed bolt 6 is installed into one of the intact threaded holes according to the actual repair situation; in this embodiment, it is preferably the threaded hole located below the eyelet 1, and at this time, the protection of this threaded hole is greater.

[0052] S20. Sheath the auxiliary positioning plate 7 corresponding to the eyelet 1 on the double-headed bolt member 6, where the positioning hole 72 on the auxiliary positioning plate 7 is matched with the convex ring portion 61 on the double-headed bolt member 6. In this embodiment, the diameter width of the positioning hole 72 is adapted to that of the convex ring portion 61; and align the guiding hole 73 on the auxiliary positioning plate 7 with the threaded hole to be repaired. In this embodiment, the diameter width of the guiding hole 73 is preferably larger than that of the threaded hole to be repaired.

[0053] S30. Pre-install the positioning column member 5 in the eyelet 1 or on the mounting plate 3, and insert the positioning end of the positioning column member 5 into the eyelet 1. Specifically, first insert the cap end of the bolt member 51 into the eyelet 1 so that the threaded end of the bolt member 51 extends out as the fixed end. Then, sequentially thread the follower member 52 onto the bolt member 51, and after placing the second wedge block 54 flat on the first wedge block 53, thread the first wedge block 53 onto the bolt member 51 and send it into the eyelet 1. At this time, to avoid too long reaction time between the first wedge block 53 and the second wedge block 54 or too short length of the entire positioning column member 5 extending into the eyelet 1, a spacer ring 74 can be provided outside the first wedge block 53, and the diameter width of the spacer ring 74 is made consistent with the diameter width of the hollow area 71 of the auxiliary positioning plate 7, and the thickness of the spacer ring 74 is the sum of the thicknesses of the hollow area 71 and the protrusion of the eyelet 1.

[0054] S40. Install the mounting plate 3 so that the fixed end passes through the first through hole and the double-headed bolt member 6 passes through the second through hole, and pre-fix the mounting plate 3 through the fastener and at least one of the double-headed bolt members 6. Then, by tightening the fastener with the fixed end, the first wedge block 53 and the second wedge block 54 are made to slide relative to each other to form a top contact with the inner wall of the eyelet 1, and the tight installation of the mounting plate 3 is completed.

[0055] S50. Set the magnetic drill 4 on the mounting plate 3, and adjust the coaxiality of the main shaft 41 of the magnetic drill 4 with the threaded hole to be repaired. Then, perform the reaming and tapping operations step by step; among them, before the reaming operation, first install a positioning rod on the magnetic drill 4, and adjust the coaxiality of the main shaft 41 of the magnetic drill 4 with the threaded hole to be repaired through the assembly relationship between the positioning rod and the guiding hole 73. For example, set the diameter width of the positioning rod to be adapted to that of the guiding hole 73, and rotate the positioning rod to insert it into the guiding hole 73, and adjust its coaxiality by judging the contact situation between the positioning rod and the inner wall of the guiding hole 73. After determining the coaxiality of the main shaft 41 of the magnetic drill 4 with the threaded hole to be repaired, replace the positioning rod with a reaming drill, and sequentially perform the reaming operation on the guiding block 8 and the threaded hole to be repaired.

[0056] S60. When performing the reaming operation, the guiding block 8 is installed corresponding to the guiding hole 73. Among them, a threaded hole can be pre-drilled on the guiding block 8, and the coaxiality with the threaded hole on the connecting flange 2 is detected by tools such as bolt columns, and after the guiding block 8 is installed, the reaming operation can be directly carried out, saving the overall working hours, and the reaming is more stable and reliable; during reaming, the single cutting amount should be strictly controlled to ensure the processing quality.

[0057] S70. After the reaming is completed and the size is detected to be qualified, the tap is replaced with the reamer and installed on the magnetic drill 4, and the magnetic drill 4 is used for auxiliary guiding to manually complete the tapping operation. After the tapping is completed, it needs to be detected to be qualified by a go-no-go gauge. After cleaning and repairing the threaded hole, a threaded bushing is installed in the repaired threaded hole, and then the magnetic drill 4 and the mounting plate 3 and other auxiliary tools are removed to complete the repair operation.

[0058] In this embodiment, the specific structural form of the steam generator can refer to the prior art and will not be elaborated here.

[0059] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A repair device for flange threaded holes under space-limited working conditions, characterized in that, It includes a mounting plate for the magnetic drill to be installed and fixed, and a positioning component; On the mounting plate, a first through-hole is provided corresponding to the eye hole of the connecting flange, several second through-holes are provided corresponding to the threaded holes of the connecting flange, and a repair machining position is reserved corresponding to the threaded hole to be repaired; The positioning component includes a positioning column member and at least one double-headed bolt member. The positioning column member includes a positioning end and a fixed end. The diameter width of the positioning end is adapted to the diameter width of the eye hole; in the installed state, the positioning end is inserted into the eye hole, and the fixed end passes through the first through-hole and is connected and fixed with a fastener; one end of the double-headed bolt member is threadedly connected to the threaded hole, and the other end of the double-headed bolt member passes through the second through-hole and is connected and fixed with a fastener; The positioning column member includes a bolt member, a follower member sleeved on the bolt member, a first wedge block sleeved on the bolt member, and several second wedge blocks arranged in a matching manner with the first wedge block; A sliding inclined surface is provided between the first wedge block and the second wedge block. The follower member can slide to contact the second wedge block as the bolt member rotates, and promote the relative sliding of the second wedge block and the first wedge block. The outer side surface of the second wedge block can slide to abut against the inner wall of the eye hole.

2. The repair device for flange threaded holes under space-constrained conditions according to claim 1, wherein, The first wedge block is arranged in a frustum shape, and several first inclined surfaces are arranged around the central axis on its outer peripheral surface; the inner side of the second wedge block is provided with second inclined surfaces corresponding to the first inclined surfaces, and the outer side of the second wedge block is provided with an arc surface adapted to the inner wall of the eye hole.

3. A repair device for flange threaded holes under space-limited working conditions according to any one of claims 1-2, characterized in that, A countersunk head structure is provided on the side of the first through-hole and the second through-hole away from the connecting flange. The connection and fixation of the fixed end and the fastener, and the connection and fixation of the double-headed bolt member and the fastener are both located in the countersunk head structure.

4. A repair device for flange threaded holes under a space-constrained working condition according to any one of claims 1-2, characterized in that, An auxiliary positioning plate is further provided between the connecting flange and the mounting plate. The auxiliary positioning plate is provided with a hollow area corresponding to the eye hole; the auxiliary positioning plate is provided with positioning holes coaxially corresponding to the threaded holes, and guiding holes coaxially corresponding to the threaded holes to be repaired.

5. The repair device for flange threaded holes under space-limited working conditions according to claim 4, characterized in that, A protrusion is provided at the eye hole, and a concave surface is provided on the side of the auxiliary positioning plate facing the eye hole corresponding to the protrusion.

6. The repair device for flange threaded holes under space-constrained working conditions according to claim 4, characterized in that, A guiding block is further provided corresponding to the guiding hole, and the guiding block is detachably installed on the auxiliary positioning plate.

7. The repair device for flange threaded holes under space-limited working conditions according to claim 6, characterized in that, A clamping groove is provided at the repair machining position corresponding to the guiding block, and the guiding block is clamped in the clamping groove.

8. A method for using a repair device for flange threaded holes under space-constrained conditions, applicable to the repair device for flange threaded holes under space-constrained conditions described in any one of the above claims 1-7, characterized in that, It includes the following steps: Pre-install the positioning column member on the mounting plate, insert the positioning end of the positioning column member into the eye hole, and set the double-headed bolt member in the intact threaded holes of at least one connecting flange to pre-fix and install the mounting plate; Set a magnetic drill on the mounting plate, adjust the coaxiality of the main shaft of the magnetic drill and the threaded hole to be repaired, and then perform reaming and tapping operations step by step; After tapping is completed, install a threaded bushing in the repaired threaded hole, and remove the magnetic drill and the mounting plate to complete the repair operation.

9. The method of using a repair device for flange threaded holes under space-limited working conditions according to claim 8, characterized in that When installing the mounting plate, an auxiliary positioning plate is arranged between the connecting flange and the mounting plate. Corresponding to the threaded holes, positioning holes are coaxially arranged on the auxiliary positioning plate, and the double-headed bolt member is inserted into the positioning holes. Corresponding to the threaded holes to be repaired, guide holes are coaxially arranged on the auxiliary positioning plate. Before reaming, first install a positioning rod on the magnetic drill, and adjust the coaxiality of the main shaft of the magnetic drill and the threaded hole to be repaired through the assembly relationship between the positioning rod and the guide holes. Guide blocks are also arranged corresponding to the guide holes. After determining the coaxiality of the main shaft of the magnetic drill and the threaded hole to be repaired, replace the positioning rod with a reaming drill, and sequentially perform reaming operations on the guide blocks and the threaded holes to be repaired.

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