Q88 Instructions
Q88E instructions. CLICK FOR HOMEPAGE

Instructions for using Q88-E line boring equipment from American Machine Tools Company. Re-Bores holes from 1 inch to 1.5 inch diameter.

It is easier when you have an extra person to help with the setup. This equipment is for reboring pivot holes up to 1.5" diameter in small earth moving equipment such as Bobcats and other Skidsteers powered by your variable speed drill with a 1/2 inch capacity drill chuck. If you are using the Q88A add on option with your Q150 equipment, then please refer to the Q150 instructions.

Q88E uses a manual feed lever to move the drill press forward

1. Using two holes to repair, insert one plastic alignment cone against the good side of each worn hole.
2. Slide the 7/8 diameter boring bar through each cone and tighten the set screws in the cones.
3. Bolt a self-aligning flange bearing to a bearing backup plate using bolts and washers. Screw on 2 standoff plates with flat head screws.
4. Slide one bearing and plate on one end of the boring bar and the drill press adapter (with built-in bearing) onto the other end. Screw 3" riser blocks to bearing plates and to drill press base. Determine where riser blocks can be tack welded to connect bearing plates to equipment to be line-bored. The 3" inch riser blocks allow easy removal of alignment cones and access for cutting tool adjustment and measuring of the hole with the digital caliper (a flashlight helps to see). Be careful not to bend the boring bar with the weight of the drill press and bearing assemblies.
5. Tack weld all stand-offs to heavy equipment to be line bored using many small tack welds to avoid warping.
6. Undo cone set screws, slide boring bar part way out and remove the cones from under the bearing plates.
7. Slide boring shaft back through the bearing.
8. Add more bearings where possible to prevent vibration during boring. We recommend at least one for every hole you wish to bore (unless there are more than 3 holes).
9. After tack welding all the bearings in place it may be necessary to loosen the bolts that hold the bearings to the plates (one bearing plate at a time) and tap the boring bar slightly because the tack welding may have warped the standoff plates, which can reduce the free movement of the shaft through the bearings.
10. Insert the drill into the hole in the drill press flange and tighten the black clamping screw lever. Carefully tighten the chuck of your drill onto the 3 flats of the shank of the boring bar.
11. Insert cutting tool into boring bar. Start boring with the cobalt steel cutter then try the carbide cutter. Use the set screw to hold the cutter to proper dimension for cutting no more than a 1/64 inch.
12. Spray cutting oil or tapping oil in hole often. If you cant get any cutting oil, WD40 can be used. Check often to make sure the drill chuck is still tight on the shank.
13. Begin cutting at low RPMs. You should be able to remove up to 1/64 per side with each pass. Keep the cutting tool bits at low RPMs by using the Velcro strap to hold the trigger position on the drill.
14. Feed the boring bar forward by gently pushing or pulling on the handle of the drill press attachment. If the cutting tool is fighting hard, apply less pressure. The height of the drill press attachment can be adjusted be loosening the black lever on the back of the drill press.
15. The left hand carbide cutting tools are for boring most types of holes. The cobalt steel cutters are great to start with and also great to finish with. They are easily sharpened. There are usually three options to repair pivot holes on heavy equipment:
16A. Holes can be welded and then bored back to the original specs. Unless you purchase a Bore Welder such as the BOA-308 this is time consuming because it requires a lot of welding. Grind off or bore out galled metal first to prevent weld hardening. Make sure you use the correct weld rod/wire for reboring with carbide cutters. 6011 rod is easier to bore than 7018 but 6011 wears faster. For MIG wire use 70S6 or 70S2. Original Spec size is the hole diameter specified by the manufacturer (such as Caterpillar) to fit the pivot shaft pin, or if there is supposed to be a bushing, then spec size is the hole sized to press fit the bushing.
16B. Holes can be bored larger than spec size, and then a sleeve can be welded into the hole or an oversize bushing can be installed if there was a bushing before. Then when the holes become worn out again simply replace the old sleeve or bushing with a new one. They are easily made on a lathe. Heat treat the sleeve to make it last longer.
16C. Bore to fit oversize bushings from a heavy equipment dealer or an industrial bearing supplier.
17. Measure using digital caliper and inside caliper or optional bore gage. To measure the cutting tool radius use the caliper from the tip of the carbide to the backside of the boring shaft.
18. If you need perfection, consider honing the last .001 of an inch of your holes.
19. When holes are finished, remove drill press assembly and bearings. Use a torch and hand grinder to remove bearing standoff plates but only when you are sure you are definitely done. NOTE: If you are careful you should use about 2 cutters per hole set. Welded holes are hard on carbide bits. Our standard equipment can bore up to about 1.5 inch diameter but be aware that extending the cutting tool bit out very far increases unwanted vibration (tool chatter). The carbide cutters can be modified or sharpened with a green silicon grinding wheel mounted on a bench/pedestal grinder. The cobalt cutters can be ground on a standard grinding wheel or belt sander. If you get a clamping screw dent in the cutting tool shank you can sand it smooth before re-adjusting tool height. All the cutting bits come shipped to you at full length. Cut the shank of a cutting tool bit with a hack saw to fit into your hole. To bore very small holes such as 1 inch diameter, you may need to grind back some of the carbide cutting tool head to fit it down into the square tool holes.

Q88E Portable Boring Rig

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