Solmet Drilling Solutions

Deep Hole Drilling

Request a QuoteDeep hole machining is an industry segment for the production of holes in long parts.  Typically, this is defined by the ratio of part length to hole diameter.  Generally speaking, this is anything in excess of 20:1 ratio up to 100:1. Longer ratios are achievable with consideration of tolerance and final part requirements.

Benefits of Deep Hole Drilling

Deep hole machining can be either or scenario of drilling, boring and skiving.  Obviously, drilling is creating a hole from solid component.  We utilize the BTA method of drilling (AKA ejector drilling).  Features of this type of drilling are close hole tolerances (+/- 0.010”) with hole straightness of approximately 0.004”/foot of length. 

Benefits of Deep Hole Drilling, ability of create a hole from solid in long length parts where there is a need for this feature.  Hole quality and surface finishes are typically very good due to a fixed diameter drill and the burnishing effect of the guide pads on the drilling tool.

Benefits of Boring

Boring is the enlarging of an existing hole to some final dimension this is similar to drilling in that machines are the same however the process can be utilized for enlarging tubing or pipe workpieces to a specific dimension.  Tolerances can be similar depending on part requirements.  In addition, hole straightness can be improved by utilizing a boring method called pull boring.

Benefits of boring, typically speaking this is a very productive method of enlarging an existing hole in a part.  This method yields consistent hole size and straightness.  We are able to handle long parts that may be cut in to small segments later to avoid later machining operations in a cnc type machine offering shorter cycle times for the final component because of limited metal removal in a closely sized bore.  Possibly only a finishing operation may be necessary if at all.

Benefits of Skiving

Skiving is another method hole processing where extremely tight tolerances can be achieved. This is similar to conventional reaming where a small depth of cut is applied to a built for purpose tool.  Typical tolerances are +/- 0.003”.  Again, this type of machining is done on our long boring machine.  Typical industries served by this type of machining are hydraulic industry for hydraulic cylinders.

Benefits of skiving are the ability to machine very tight tolerance holes over long lengths.  Skiving is frequently seen in the hydraulic cylinder manufacturing industry or the sizing of DOM tubing for hydraulics.    

Benefits of Honing

Honing is a method ID grinding for close tolerance work as well as high quality surface finishes.  This process utilizes a purpose-built machine where the tool is stroked in the bore removing small amounts of material per stroke.  

Benefits of honing are the close tolerance of an ID in a part in addition to fine finishes achievable.

Solmet DEEP HOLE Drilling Capabilities 

Short Single End Drilling    
Min OD 3.5 1.75
Max OD 13 7.25
Min ID 2 0.75
Max ID 6 2.625
Min length 20 11.5
Max length 60 50
Material capability all all
Max weight (lbs.) 5000 5000
Max RPM 389 565


Min OD 2
Max OD 17.5
Min ID 1.75
Max ID 13.313
Min length 18
Max length 378
Material capability all
Max weight (lbs.) 15000
Max RPM 242


Compound Single
Min OD 3.5
Max OD 12.375
Max OD through spindle 12
Std. Tolerance +0.060"/-0.0" 16.5
Min length 24
Max length 204
Material capability all
Max length 408
Max weight (lbs.) 10000
Max RPM 418


Pull Bore  
Min OD 3
Max OD 16.5
Min ID 2.25
Max ID 13.375
Min length 52
Max length 408
Material capability all
Max weight (lbs.) 5000
Max RPM 250


Min OD 2.5
Max OD 8
Min length 72
Max length 420
Material capability all
Max weight (lbs.) 15000


Single & Double End Drilling      
Min OD 3 2 1.75
Max OD Chuck to Chuck 12.5 9 5
Max OD with sleeves 9.5 7.25 5
Min ID 2 0.75 5
Max ID 5.35 2.5 2.25
Min Length 54 44 44
Max Length Chuck to Chuck 120 108 84
Max length both ends (double end) 288 252 252
Max length one end only 1"-3/4" 120 84 84
Max length one end only >1" dia 144 132 132
Material capability all all all
Max RPM 602 1200 1840
Max weight (lbs.) 10000 1200 1841